Defectos Infraoseos y Regeneracion

7/28/2019 Defectos Infraoseos y Regeneracion

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Periodontology 2000, Vol. 22, 2000, 104132 Copyright C Munksgaard 2000Printed in Denmark All rights reserved

PERIODONTOLOGY 2000ISSN 0906-6713

Focus on intrabony defects:guided tissue regenerationPIERPAOLO CORTELLINI & MAURIZIO S . TONETTI

The American Academy of Periodontology has de-

fined regeneration as the reproduction or reconstitu-

tion of a lost or injured part to restore the architec-

ture and function of the lost or injured tissues. Peri-

odontal regeneration is defined as regeneration of

the tooth-supporting tissues including cementum,

periodontal ligament and alveolar bone (41).

Melcher (61) suggested that the cells that repopu-late the root surface after periodontal surgery deter-

mine the nature of the attachment that will form.

Following flap elevation, the instrumented root sur-

face can be repopulated by epithelial cells, gingival

connective tissue cells, bone cells and periodontal

ligament cells. Under normal healing conditions,

epithelial cells rapidly migrate in an apical direction

to reach the most apical portion of the instrumen-

tation, forming a long junctional epithelium (10, 14,

57, 72) and preventing the formation of a new

attachment.

The aim of regenerative procedures is to displace

the epithelial attachment at a more coronal position

than before treatment, allowing cells from peri-

odontal ligament and bone to repopulate the root

surface and to form a new periodontal attachment

(49, 50, 62, 72).

The biological concept of guidedtissue regeneration

Guided tissue regeneration with barrier membranes

has been demonstrated to be effective in preventing

epithelial and gingival connective tissue cells from

migrating into the blood clot about the instru-

mented root surface (44, 45, 71, 73). A physical bar-

rier (membrane) is placed to cover the area in which

the regenerative process is to take place. The barrier

is properly shaped and positioned to form a space

around the bony defect and the root surface. In the

space under the barrier, cells from periodontal liga-

104

ment and bone colonize the blood clot, expressing

their potential for regeneration. Cementum, peri-

odontal ligament and alveolar bone are expected to

form.

Clinical and histological outcomes

The clinical methods to evaluate the outcomes of a

regenerative therapy include assessment of peri-

odontal probing (pocket depth and clinical attach-

ment levels) and bone levels (re-entry procedures,

bone sounding and radiographs) (41). Histological

evaluation, however, remains the only reliable

method of determining the nature of the attachment

apparatus resulting from regenerative procedures.

Several studies in animals (3, 4, 12, 13, 15, 43, 44, 71)

and some human biopsy material (8, 20, 32, 45, 73,

80, 81) have documented that guided tissue re-

generation is capable of promoting new attachment

formation.

The overall treatment rationale of applying guided

tissue regeneration in deep intrabony defects comes

from the need to increase the periodontal support in

teeth severely compromised by periodontal disease.

The clinical goals of the use of regenerative pro-

cedures are improvements in the local anatomy and/

or the functioning and prognosis of teeth. The major

benefits the patient can expect from guided tissue

regeneration treatment are improved masticatory

function, comfort and prognosis of the involvedteeth, with minor detriment to the aesthetic appear-

ance. The primary outcomes in the treatment of in-

trabony defects are (i) increase in functional tooth

support (clinical attachment and bone levels); (ii) re-

duction in pocket depth; and (iii) minimal gingival

recession. Since human biopsy material is very dif-

ficult to obtain, for ethical reasons, the cited out-

comes should be interpreted as evidence of im-

proved healing response in the lack of histological

evidence (56).


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Focus on intrabony defects: guided tissue regeneration

Clinical evidence

The year 1982 was the starting-point of guided tissue

regeneration (73). Following the first case published

by Sture Nyman, other authors (7, 22, 45, 76) re-

ported encouraging results in independent case

series. That evidence, in fact, demonstrated that ap-

plying guided tissue regeneration to deep intrabonydefects could promote significant clinical improve-

ments in terms of clinical attachment and bone

gains and reducing pocket depth. These pioneering

experiences have opened the road to a new era of

excitement in the periodontal field. The original ex-

citement, however, was soon followed by a great deal

of frustration, since clinicians found it very difficult

to predictably duplicate the clinical outcomes re-

ported in the cited studies in daily practice. The ap-

plication of the biological concept of guided tissue

regeneration appeared to be very difficult and

affected by many different unknown variables.The turning point in the guided tissue regenera-

tion arena was the year 1993, when the clinical out-

comes of a group of 40 intrabony defects treated

with non-resorbable expanded polytetrafluoroethy-

lene membranes were analyzed with a multivariate

statistical approach with the aim of isolating the rel-

evant variables that could influence the healing re-

sponse and the final clinical outcomes of guided

tissue regeneration (23, 31, 32, 85, 89). The results

from the cited studies demonstrated that the vari-

ability in clinical outcomes was affected by patient-,

defect- and procedure-associated factors. Under-

standing the factors determining the clinical out-

comes rendered their control, at least in part, poss-

ible, allowing remarkable improvements in their ex-

tent and predictability (Fig. 1).

At the end of 1997, 35 scientific investigations had

been published and reported 943 intrabony defects

treated with guided tissue regeneration (Table 1) (1,

57, 9, 11, 1619, 21, 24, 26, 27, 2931, 33, 38, 39, 46,

48, 5153, 55, 59, 63, 67, 74, 75, 77, 84, 88). These

studies have addressed the issue of the evaluation of

the extent and predictability of the clinical outcomesfollowing application of guided tissue regeneration.

The weighted mean of the reported results indicates

gains in clinical attachment of 3.861.69 mm and

residual probing pocket depths of 3.351.19 mm.

Different types of nonresorbable and resorbable

barrier membranes have been used in the cited

studies. Guided tissue regeneration treatment of 351

defects (20 studies) with nonresorbable barrier

membranes resulted in clinical attachment level

gains of 3.71.8 mm; this was similar to the results

105

Fig. 1. Plot of some of the clinical studies on guided tissue

regeneration published between 1988 and 1998. The dots

(red for nonresorbable barriers and blue for resorbable

barriers) indicate the average probing attachment level

(PAL) gain reported by each author. The yellow line, con-

necting some of the studies published by the group of

Cortellini, Pini Prato & Tonetti, shows the improvements

obtained by these clinicians through time in terms of

probing attachment level gains. Such improvements were

achieved by controlling the critical factors involved in the

guided tissue regeneration procedure.

obtained treating 592 intrabony defects (17 studies)

with bioresorbable barrier membranes (3.61.5

mm).

The reported outcomes indicate that the appli-

cation of nonresorbable or bioresorbable barrier

membranes consistently and predictably results in

clinical improvements in intrabony defects. The ef-

ficacy of guided tissue regeneration treatment of

infrabony defects has been evaluated in 11 ran-

domized controlled clinical trials in which guided

tissue regeneration has been directly compared with

access flap surgery (Table 2) (1, 18, 19, 27, 33, 52, 53,

59, 74, 75, 84). A total of 213 defects treated with

access flap and 243 defects treated with guided

tissue regeneration were included in these studies.

Ten of the 11 investigations concluded that guided

tissue regeneration resulted in statistically and clin-

ically significant greater probing attachment level

gains when compared to the access flap. The onlyinvestigation reporting no significant differences be-

tween guided tissue regeneration and access flap

surgery was carried out in only 9 pairs of defects

located on maxillary premolars; in this study the in-

trabony component of the defects was shallow and

10 of the 18 defects had a furcation involvement (74).

The weighted mean of the evidence reported in the

11 studies listed in Table 2 indicated that the gain of

clinical attachment in sites treated with guided

tissue regeneration was 3.41.8 mm (95% confi-


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Cortellini & Tonetti

Table 1. Clinical studies on guided tissue regeneration with nonresorbable and bioresorbable barriermembranes

Probing Probing pocketAuthors Type of barrier n attachment gain SD depth at 1 year SD

Becker et al. (7) Expanded polytetrafluoroethylene 9 4.5 1.7 3.2 1

Chung et al. (18) Collagen 10 0.6 0.6

Handelsman et al. (48) Expanded polytetrafluoroethylene 9 4 1.4 3.9 1.4

Quteish et al. (75) Collagen 26 3 1.5 2.19 0.44Selvig et al. (77) Expanded polytetrafluoroethylene 26 0.8 1.3 5.4

Proestakis et al. (74) Expanded polytetrafluoroethylene 9 1.2 1.3 3.5 0.88

Kersten et al. (51) Expanded polytetrafluoroethylene 13 1 1.1 5.1 0.9

Becker et al. (5) Expanded polytetrafluoroethylene 32 4.5 3.88 0.26

Cortellini et al. (20) Expanded polytetrafluoroethylene 40 4.1 2.5 2 0.6

Falk et al. (38) Polymer 25 4.5 1.6 3 1.1

Laurell et al. (55) Polymer 47 4.9 2.4 3 1.4

Cortellini et al. (21) Rubber dam 5 4 0.7 2.4 0.5

Cortellini et al. (27) Expanded polytetrafluoroethylene 15 4.1 1.9 2.7 1Titanium-reinforced expanded 15 5.3 2.2 2.1 0.5

polytetrafluoroethylene

Al-Arrayed et al. (1) Collagen 19 3.9 2.5Cortellini et al. (24) Expanded polytetrafluoroethylene 14 5 2.1 2.6 0.9

Expanded polytetrafluoroethylene 14 3.7 2.1 3.2 1.8

Mattson et al. (59) Collagen 13 2.5 1.5 3.6 0.6Collagen 9 2.4 2.1 4 1.1

Cortellini et al. (26) Expanded polytetrafluoroethylene 11 4.5 3.3 1.7Expanded polytetrafluoroethylene 1 1 3.3 1.9 1.9

Mellado et al. (63) Expanded polytetrafluoroethylene 11 2 0.9

Chen et al. (16) Collagen 10 2 0.4 4.2 0.4

Cortellini et al. (33) Expanded polytetrafluoroethylene 12 5.2 1.4 2.9 0.9Polymer 12 4.6 1.2 3.3 0.9

Tonetti et al. (88) Expanded polytetrafluoroethylene 23 5.3 1.7 2.7

Becker et al. (6) Polymer 30 2.9 2 3.6 1.3

Kim et al. (53) Expanded polytetrafluoroethylene 19 4 2.1 3.2 1.1Gouldin et al. (46) Expanded polytetrafluoroethylene 25 2.2 1.4 3.5 1.3

Murphy (67) Expanded polytetrafluoroethylene 12 4.7 1.4 2.9 0.8

Cortellini et al. (29) Polymer 10 4.5 0.9 3.1 0.7

Falk et al. (39) Polymer 203 4.8 1.5 3.4 1.6

Caffesse et al. (11) Polymer 6 2.3 2 3.8 1.2Expanded polytetrafluoroethylene 6 3 1.2 3.7 1.2

Kilic et al. (52) Expanded polytetrafluoroethylene 10 3.7 2 3.1 1.4

Benque et al. (9) Collagen 52 3.6 2.2 3.9 1.7

Christgau et al. (7) Expanded polytetrafluoroethylene 10 4.3 1.2 3.6 1.1Polymer 10 4.9 1 3.9 1.1

Cortellini et al. (30) Polymer 18 4.9 1.8 3.6 1.2

Tonetti et al. (84) Polymer 69 3 1.6 4.3 1.3

Cortellini et al. (19) Polymer 23 3 1.7 3 0.9

Weighted mean 943 3.86 1.69 3.35 1.19

dence interval 3.03.7 mm), while the access flap re-

sulted in a mean gain of 1.81.4 mm (95% confi-

dence interval 1.52.1 mm). The analysis of the re-

ported clinical outcomes strongly suggests an added

benefit deriving from the placement of barrier mem-

106

branes after elevation of an access flap. This im-

pression is reinforced by the lack of overlap observed

in the 95% confidence intervals.

The data reported in some of the studies summar-

ized in Table 1 (651 defects in 17 investigations (9,


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Table 2. Controlled clinical trials comparing guided tissue regeneration procedure with access flap pro-cedures

Guided tissuen (guided regeneration Flap probingtissue probing attachment attachment

Authors Type of membrane regeneration) gainSD (mm) n (flap) gainSD (mm)

Chung et al. (18) Collagen 10 0.60.6 10 0.70.9

Quteish & Dolby (75) Collagen 26 3.01.5 26 1.80.9

Proestakis et al. (74) Expanded polytetrafluoroethylene 9 1.22.0 9 0.61.0

Al-Arrayed et al. (1) Collagen 14 3.9 14 2.7

Mattson et al. (59) Collagen 9 2.42.1 9 0.42.1

Cortellini et al. (27)* Expanded polytetrafluoroethylene 15 4.11.9 15 2.50.8

Cortellini et al. (27) Titanium-reinforced expanded 15 5.32.2 polytetrafluoroethylene

Cortellini et al. (33)* Expanded polytetrafluoroethylene 12 5.21.4 12 2.30.8

Cortellini et al. (33) Polymer 12 4.61.2

Kim (53) Expanded polytetrafluoroethylene 19 4.02.1 18 2.01.7

Kilic (52) Expanded polytetrafluoroethylene 10 3.72.0 10 2.12.0

Tonetti (84) Polymer 69 3.01.6 67 2.21.5

Cortellini (19) Polymer 23 3.01.7 23 1.61.8

Weighted mean 243 3.41.8 213 1.81.4

* Three-arm studies. Comparisons were made among two different barrier membranes and access flap.

1719, 27, 2931, 33, 38, 39, 48, 55, 59, 75, 84, 88)

allowed a further analysis to address the issue of pre-

dictability of obtaining relevant amounts of attach-

ment level gains in intrabony defects. The frequency

distribution of clinical attachment level changes at 1

year has been evaluated subdividing the data in 5

classes of probing attachment level changes: loss of

attachment, gain of 01 mm, gain of 23 mm, gain

of 45 mm and gain of 6 mm or more. Only 2.7% of

651 treated cases lost attachment, while gains of less

than 2 mm were observed in 11% of the cases. Most

of the sites gained considerable attachment. In fact,

gains of 23 mm were observed in 24.8% of the cases,

gains of 45 mm in 41.3%, and gains of 6 mm or

more in 21.2% of defects. These encouraging data

demonstrate that guided tissue regeneration is not

only efficacious, but also predictable.

Five investigations reported changes in bone

levels (7, 32, 48, 51, 78). Bone gains ranged from 1.1mm to 4.3 mm and seemed to correlate well with

the gains in clinical attachment. The existence of a

correlation between gains in clinical attachment and

gains in bone levels in intrabony defects was demon-

strated in an investigation by Tonetti et al. (89). In

this study, the expected position of the bone 1 year

after guided tissue regeneration was consistently

found to be located 1.5 mm apical to the position of

the clinical attachment.

Reduction of pocket depths is one of the critical

107

endpoints of most periodontal procedures, including

guided tissue regeneration. An important parameter

to evaluate the successful outcomes of guided tissue

regeneration, therefore, is the depth of the residual

pockets. In most of the studies listed in Table 1, shal-

low pockets were consistently measured at 1 year.

The weighted mean of residual pocket depths was

3.31.2 mm, with a 95% confidence interval ranging

from 3.2 to 3.5 mm. It is interesting to note that deep

residual pockets (greater than 5 mm) were observed

in only two studies, which reportedly resulted in

minimal amounts of attachment and bone gains (51,

78).

Factors affecting the clinicaloutcomes

The primary factors affecting the clinical outcomesof periodontal surgery have been classified by Korn-

man in this volume as: 1) bacterial contamination,

2) innate wound-healing potential, 3) local site

characteristics and 4) surgical procedure. These fac-

tors have been summarized in an influence diagram

to illustrate how various factors influence regenera-

tion.

The information used to build the influence dia-

gram primarily derive from studies in which multi-

variate approaches have been employed to identify


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factors associated with the observed clinical out-

comes (58, 8587). These studies have evaluated

three types of possible sources of variability: (i) the

patient; (ii) the morphology of the defect; (iii) the

guided tissue regeneration procedure and the heal-

ing period.

The patient

Physiological, environmental, behavioral and gen-

etic patient factors may affect the healing outcome

of guided tissue regeneration procedures. So far, a

highly significant environmental exposure, cigarette

smoking, has been associated with reduced out-

comes (86). The ability to maintain high levels of

plaque control has also been associated with im-

proved outcomes (23, 28, 86, 87). Since these factors

can be controlled through behavioral interventions,

clinicians should discuss with the patient the oppor-

tunity to further improve hygiene and discontinuethe smoking habit. Another important variable as-

sociated with guided tissue regeneration outcomes

is the level of residual periodontal infection in the

dentition, evaluated clinically as the percentage of

sites with bleeding on probing, or microbiologically

as the persistence of periodontal pathogens after

completion of initial therapy (58, 85). A clinical im-

plication of such observation is to defer guided

tissue regeneration procedures until the periodontal

infection is adequately controlled. Despite the lack

of direct evidence, other factors, such as diabetes,

intraoral accessibility and stressful life events,

should be kept in mind in patient selection.

The defect

Defect morphology plays a major role in the healing

response of guided tissue regeneration therapy in in-

trabony defects. It has been demonstrated that

greater amounts of clinical attachment and bone can

be gained in deeper defects (42, 85, 87). Defects

deeper than 3 mm have been found to result consist-

ently in greater probing attachment gains than de-fects of 3 mm or less (19). The potential for regenera-

tion, however, has been reported to be similar in

deep and shallow defects. In fact, in the cited study

(19) similar results were observed in shallow and

deep defects, when probing attachment gains were

expressed as a percentage of the baseline intrabony

component of the defects. Another important

morphological characteristic is the width of the in-

trabony component of the defect, measured as the

angle that the bony wall of the defect forms with the

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long axis of the root (82). Wider defects have been

associated with reduced amounts of probing attach-

ment level gain and bone fill at 1 year (85). In a re-

cent study on 242 intrabony defects, defects with a

radiographic defect angle of 25 or less gained con-

sistently more attachment (1.5 mm on average) than

defects of 37 or more (35).

Two investigations failed to demonstrate a sig-nificant association between the number of residual

bony walls and the clinical outcomes (85, 87). In one

study, clinical improvements were associated with

the depth of the three-wall intrabony component of

the defect (78). All investigations agree on the lack

of significance of defect circumference and/or num-

ber of tooth surfaces involved (78, 85, 87). In a study,

gingival thickness of less than 1 mm was associated

with higher prevalence and severity of flap dehis-

cence over the membrane (2).

Based on this evidence and the treatment objec-

tives, deep and narrow defects are the ones that maybenefit most from guided tissue regeneration treat-

ment. It is also desirable to surgically manipulate

thick tissues for membrane coverage and thus re-

duce the occurrence of flap dehiscence.

The guided tissue regeneration procedure andthe healing period

Evidence from 2 randomized, controlled clinical tri-

als indicates that the choice among different guided

tissue regeneration strategies affects the expected

outcomes resulting in significantly greater improve-

ments in clinical attachment levels (24, 27, 87). Dif-

ferent membranes, i.e. resorbable vs. non-resorbable

or self-supporting membranes, possess different

abilities to create and maintain the necessary space

for regeneration. Different surgical approaches to ac-

cess the interdental spaces, to preserve tissues and

to protect the area of regeneration, are associated

with different outcomes.

In particular, membrane exposure is a major com-

plication of guided tissue regeneration with a preva-

lence in the 70% to 80% range (7, 22, 31, 36, 37, 65,78). Membrane exposure has been reported to be

highly reduced (range 40 to 5%) with the use of ac-

cess flaps specifically designed to preserve the inter-

dental tissues (25, 29, 30, 67, 84). This is a relevant

issue, since membranes exposed to the oral environ-

ment have been shown to be contaminated by bac-

teria (36, 37, 47, 58, 64, 6870, 77, 79, 83). Several

independent studies have associated contamination

of both non-resorbable and resorbable membranes

with reduced amounts of probing attachment gains


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Fig. 2. Conventional technique. Man- Fig. 3. Conventional technique. After Fig. 4. Conventional technique. At

dibular right cuspid: the preoperative flap elevation a 7-mm two- and three- week 2, the nonresorbable barrier

pocket depth was 5 mm and the prob- wall defect was exposed. The total membrane was partially exposed and

ing attachment level 11 mm. depth of the defect measured 12 mm. thus contaminated.

Fig. 5. Conventional technique. The re- Fig. 6. Conventional technique. The re- Fig. 7. Conventional technique. At 1

generated tissue appeared inflamed at generated tissue was not properly pro- year, the residual pocket depth was 4

membrane removal. tected in the interproximal area. mm. A gain of 3 mm of clinical attach-

ment and a substantial increase of the

gingival recession were measured.

(36, 37, 69, 70, 77). Antimicrobial prophylaxis of ex-

posed membranes has been shown to be effective in

reducing the bacterial load but ineffective in pre-

venting biofilm formation (40, 69). This evidence

109

suggests the importance of keeping the membranes

submerged to obtain optimal results. Further, reduc-

tion of bacterial load by an appropriate anti-

microbial approach may reduce the negative effects


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Fig. 8. Conventional technique. Baseline radiograph.

Fig. 9. Conventional technique. One-year radiograph.

associated with membrane contamination. The

choice of the surgical approach and of a specific type

of barrier membrane is therefore a critical clinical

decision. Finally, operator skill may influence the

clinical outcomes (84). Different ability in tissue

management, membrane manipulation, attention to

blood supply, suturing technique and other factors

may play a major role in a difficult procedure such

as guided tissue regeneration. Other components of

operator skill may relate to the individual skills in

110

patient and site selection and postoperative man-

agement.

The guided tissue regenerationprocedures

Various surgical approaches and suturing techniqueshave been proposed in the literature. Clinicians

should incorporate in their clinical armamentarium

all the possible alternatives to optimize the pro-

cedure.

Conventional approach

The conventional approach consists of a flap ap-

proach (access flap or modified Widman flap) not

specifically designed for use with barrier membranes

(7, 22, 31, 48). Full-thickness flaps are elevated to try

to preserve the marginal and the interdental tissuesto the maximum possible extent. Vertical releasing

incisions are performed as needed to increase defect

accessibility. Periosteal incisions are normally per-

formed to allow coronal displacement of the flap and

to improve the ability to cover the membrane. Mat-

tress and passing sutures are placed in the inter-

proximal spaces in order to attempt primary closure

of the interdental tissues over the membranes (Fig.

29).

This approach normally does not allow a com-

plete preservation of the interdental papilla, there-

fore rendering very difficult the primary closure of

the interdental tissues over the membrane. Major

complications are gingival dehiscence and mem-

brane exposure.

Modified papilla preservation technique

The rationale for developing this technique was to

achieve and maintain primary closure of the flap in

the interdental space over the membrane (Fig. 10

15). Access to the interproximal defect consists of a

horizontal incision traced in the buccal keratinizedgingiva at the base of the papilla, connected with

mesiodistal buccal intrasulcular incisions. After elev-

ation of a full-thickness buccal flap, the residual in-

terproximal tissues are dissected from the neigh-

boring teeth and the underlying bone and elevated

towards the palatal aspect. A full-thickness palatal

flap, including the interdental papilla, is elevated

and the interproximal defect exposed. Following de-

bridement of the defect, the buccal flap is mobilized

with vertical and periosteal incisions, when needed.


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Fig. 13. Modified papilla preservation technique. The in-Fig. 10. Modified papilla preservation technique. Access toterproximal defect after debridement.the defect was gained with a buccal horizontal incision at

the base of the papilla.

Fig. 14. Modified papilla preservation technique. A ti-Fig. 11. Modified papilla preservation technique. A buccaltanium-reinforced barrier membrane was positioned nearfull-thickness flap was elevated. The defect-associated pa-to the cementoenamel junction.pilla is still in place.

Fig. 12. Modified papilla preservation technique. The pa- Fig. 15. Modified papilla preservation technique. Primarypilla was elevated along with the full-thickness palatal closure of the interdental space was ensured with a hori-flap. zontal internal crossed mattress suture to relieve the ten-

sion of the flaps and a second suture to close the interden-

tal papilla.

111


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Fig. 16, 17. Modified papilla preservation technique.

Drawing of the horizontal internal crossed mattress su-

ture. The suture runs under the flaps, hanging on top of

the titanium reinforcement of the membrane. The buccal

flap is coronally displaced.

This technique was originally designed for use in

combination with self-supporting barrier mem-

branes (25). In fact, the suturing technique requires a

supportive (or supported) membrane to be effective

(Fig. 16, 17). To obtain primary closure of the inter-

dental space over the membrane, a first suture (hori-

zontal internal crossed mattress suture) is placed be-

neath the mucoperiosteal flaps between the base of

the palatal papilla and the buccal flap. The interproxi-

mal portion of this suture hangs on top of the mem-

brane allowing the coronal displacement of the buc-

calflap. This suture relievesall thetension of the flaps.

To ensure passive primary closure of the interdental

tissues over themembrane, a second suture (a verticalinternal mattress suture)is placed between the buccal

aspect of the interproximal papilla (that is, the most

coronal portion of the palatal flap that includes the

interdental papilla) and the most coronal portion of

the buccal flap. This suture is free of tension.

An alternative type of suture to close the interden-

tal tissues has been proposed by Laurell (54). This

modified internal mattress suture (Fig. 18, 19) starts

from the external surface of the buccal flap, crosses

the interdental area and passes through the lingual

112

flap at the base of the papilla. The suture runs back

through the external surface of the lingual flap and

the internal surface of the buccal flap, about 3 mm

apart from the first two bites. Finally, the suture is

passed through the interproximal area above the

papillary tissues, passed through the loop of the su-

ture on the lingual side and brought back to the buc-

cal side, where it is tied. This suture is very effectivein ensuring stability and primary closure of the

interdental tissues.

In a randomized controlled clinical study of 45 pa-

tients (27), significantly greater amounts of probing

attachment were gained with the modified papilla

preservation technique (5.32.2 mm), in compari-

son with either conventional guided tissue regenera-

tion (4.11.9 mm) or access flap surgery (2.50.8

mm), demonstrating that a modified surgical ap-

proach can result in improved clinical outcomes.

The sites accessed with the modified papilla preser-

vation technique showed primary closure of the flapin all but one case, and no gingival dehiscence until

membrane removal, in 73% of the cases (Fig. 2040).

This surgical approach has been also attempted in

combination with non-supported bioresorbable bar-

rier membranes (29), with positive results. Clinical

Fig. 18, 19. A modification of the suture described in Fig.

15 and 16, described by L. Laurell. This suture ensures

also an external stabilization to the interproximal tissues.


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Fig. 20. Modified papilla preservation technique. A 10 mm Fig. 23. Modified papilla preservation technique. Primarypocket on the mesial surface of the upper left central in- closure of the interdental tissues was achieved over thecisor. membrane.

Fig 24. Modified papilla preservation technique. PrimaryFig. 21. Modified papilla preservation technique. After de-

closure was maintained at week 5. The gingiva wasbridement a one- and three-wall combination intrabonyhealthy.defect was evident.

Fig. 25. Modified papilla preservation technique. AfterFig. 22. Modified papilla preservation technique. A ti-membrane removal a mature, rich in collagen and un-tanium-reinforced barrier membrane was positioned atinflamed tissue was evident.the level of the cementoenamel junction.

113


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Fig. 26. Modified papilla preservation technique. The re-

generated tissue was properly protected with the gingival

flaps.

attachment level gains at 1 year were 4.50.9 mm. In

all the cases primary closure of the flap was achieved,and about 80% of the sites maintained primary clo-

sure over time (Fig. 4148). It should be emphasized,

however, that the horizontal internal crossed mattress

suture most probably caused an apical displacement

of the interproximal portion of the membrane, there-

by reducing the space for regeneration.

The surgical access of the interproximal space

with the modified papilla preservation technique is

Fig. 28. Modified papilla preservation Fig. 29. Modified papilla preservation Fig. 30. Modified papilla preservation

technique. Baseline radiograph. technique. One-year radiograph show- technique. Upper right cuspid: the in-

ing almost complete resolution of the trabony defect is 14 mm deep.

defect.

114

Fig. 27. Modified papilla preservation technique. At 1 year,

no recession of the interdental tissues was observed. The

pocket depth was reduced to 3 mm with a gain of attach-

ment of 7 mm.

technically very demanding, but it has been reported

to be very effective and applicable in wide interden-tal spaces (wider than 2 mm at interdental tissue

level), especially in the anterior dentition. In prop-

erly selected cases, large amounts of attachment

gain and consistent reduction of pocket depths as-

sociated with no or minimal recession of the inter-

dental papilla are consistently expected. It is, there-

fore, especially indicated in cases in which aesthetics

is particularly important.


12/29


Fig. 31. Modified papilla preservation Fig. 32. Modified papilla preservation Fig. 33. Modified papilla preservationtechnique. Two membranes were su- technique. Baseline radiograph, show- technique. One-year radiograph: thetured together to cover all the apicoco- ing radiolucency up to the apex of the intrabony defect was almost com-ronal extension of the defect. tooth. pletely resolved.

Simplified papilla preservation flap

To overcome some of the technical problems en-

countered with the modified papilla preservation

technique, including difficult application in narrow

interdental spaces and in posterior areas and a su-

turing technique not appropriate for use with non-

supportive barriers, a different approach, the simpli-

fied papilla preservation flap (Fig. 4958), was subse-

quently developed (30).

This different and simplified approach to the

interdental papilla includes a first incision across the

Fig. 34. Modified papilla preservation technique. Upper

right central incisor: the intrabony defect is deeper than

15 mm. Total bone loss is greater than 20 mm.

115

defect associated papilla, starting from the gingival

margin at the buccal-line angle of the involved tooth

to reach the mid-interproximal portion of the papilla

under the contact point of the adjacent tooth. This

oblique incision is carried out keeping the blade par-

allel to the long axis of the teeth to avoid excessive

thinning of the remaining interdental tissues. The

first oblique interdental incision is continued intra-

sulcularly in the buccal aspect of the teeth neigh-

boring the defect. After elevation of a full-thickness

buccal flap, the remaining tissues of the papilla are

carefully dissected from the neighboring teeth and

Fig. 35. Modified papilla preservation technique. Lingual

view showing the severity and extension of the bone de-

struction.


13/29


Fig. 36, 37. Modified papilla preservation technique. A ti-

tanium-reinforced barrier membrane positioned to iso-

late the defect (buccal and lingual view).

Fig. 38. Modified papilla preservation technique. One-year

re-entry surgery. The distance from the cementoenameljunction and the bottom of the defect was 10 mm: the

bone gain was greater than 10 mm.

the underlying bone crest. The interproximal papil-

lary tissues at the defect site are gently elevated

along with the lingual/palatal flap to fully expose the

interproximal defect. Following defect debridement

and root planing, vertical releasing incisions and/or

periosteal incisions are performed, when needed, to

116

improve the mobility of the buccal flap. After appli-

cation of a barrier membrane, primary closure of the

interdental tissues above the membrane is

attempted in the absence of tension, with the follow-

ing sutures: 1) a first horizontal internal mattress su-

ture (offset mattress suture) is positioned in the de-

fect-associated interdental space running from the

base (near the mucogingival junction) of the kera-

Fig. 39. Modified papilla preservation technique. Baseline

radiograph.

Fig. 40. Modified papilla preservation technique. One-year

radiograph. The defect was almost completely resolved.


14/29


Fig. 41. Modified papilla preservation technique with bio-

resorbable membranes. Upper left central incisor at base-

line.


resorbable membranes. A deep one-, two- and three- wall

combination defect was evident after debridement.


resorbable membranes. A bioresorbable barrier was posi-

tioned.

117


resorbable membranes. Primary closure of the interproxi-

mal tissues was obtained over the bioresorbable mem-

brane.


resorbable membranes. Primary closure was maintained

through time.


resorbable membranes. At one-year, the final fixed recon-

struction was placed.


15/29



resorbable membranes. Baseline radiograph.


resorbable membranes. One-year radiograph.

tinized tissue at the mid-buccal aspect of the tooth

not involved by the defect to a symmetrical location

at the base of the lingual/palatal flap. This suture

rubs against the interproximal root surface, hangs on

the residual interproximal bone crest and is an-

chored to the lingual/palatal flap. When tied, it

allows the coronal positioning of the buccal flap. A

relevant notation is that this suture, laying on the

118

Fig. 49. Simplified papilla preservation flap. Upper right

lateral incisor at baseline.

Fig. 50. Simplified papilla preservation flap. The pocketdepth and the attachment level were 9 mm and 11 mm,

respectively.

Fig. 51. Simplified papilla preservation flap. The intrabony

defect was a deep one-wall defect with a shallow three-

wall component at the bottom. Note the bone crest ad-

jacent to the central incisor.


16/29


Fig. 52. Simplified papilla preservation flap. A bioresorb-

able barrier membrane was positioned to cover the defect.

Fig. 53. Simplified papilla preservation flap. Primary clo-

sure of the defect-associated interproximal space. Note

the offset suture positioned on the buccal side of the cen-

tral incisor.

Fig. 54. Simplified papilla preservation flap. The treated

area at 1 year. Probing depth is 2 mm.

interproximal bone crest, does not cause any com-

pression at the mid-portion of the membrane, there-

fore preventing its collapse into the defect. 2) The

119

interdental tissues above the membrane are then su-

tured to obtain primary closure with one of the fol-

lowing approaches: a) one interrupted suture when-

ever the interproximal space is narrow and the inter-

dental tissues thin; b) two interrupted sutures, when

the interproximal space is wider and the interdental

tissues thicker; c) an internal vertical/oblique mat-

tress suture (25), when the interproximal space is

Fig. 55. Simplified papilla preservation flap. Baseline

radiograph.

Fig. 56. Simplified papilla preservation flap. One-year

radiograph.


17/29


Fig. 57, 58. Simplified papilla preservation flap. Drawing

representing the offset mattress suture. This suture rubs

against the root surface of the tooth approximal to the

defect, hangs on the residual bone crest preventing the

apical displacement of the resorbable barrier membrane.

wide and the interdental tissues thick. Special care

has to be paid to ensure that the first horizontal mat-

tress suture would relieve all the tension of the flaps,

and to obtain primary passive closure of the inter-

dental tissues over the membrane with the last su-

ture. When tension is observed, the sutures should

be removed and the primary passive closure

attempted a second time.

This approach has been preliminarly tested in a

case series of 18 deep intrabony defects in combi-

nation with bioresorbable barrier membranes (30).

The average clinical attachment level gain observed

at 1 year was 4.91.8. In all the cases it was possible

to obtain primary closure of the flap over the mem-brane, and 67% of the sites maintained primary clo-

sure over time. The same approach was then tested

in a multicenter controlled randomized clinical trial

involving 11 clinicians from 7 different countries and

a total of 136 defects (84). The average clinical

attachment gain observed at 1 year in the 69 defects

treated with the simplified papilla preservation flap

and a resorbable barrier membrane was 31.6 mm.

More than 60% of the treated sites maintained pri-

mary closure over time. It is important to underline

120

that these results were obtained by different clini-

cians treating different populations of patients and

defects including also narrow spaces and posterior

areas of the mouth.

Interdental tissue maintenance

Interproximal tissue maintenance is a techniqueproposed by Murphy (67) to be used in combination

with nonresorbable barrier membranes and grafting

material. It involves the reflection of a triangularly

shaped palatal flap that remains contiguous with the

buccal portion of the flap. The triangularly shaped

palatal tissue is referred to as the papillary triangle.

The isthmus of tissue that connects the papillary tri-

angle with the buccal flap provides the primary

coverage for the interproximal guided tissue re-

generation material during wound healing. The suc-

cess of this technique depends upon the following

factors: excellent preoperative tissue tone and ab-sence of local inflammation; the thickness of the

palatal tissue; the use of wide, inverse bevelled pala-

tal incisions; a minimal interradicular width of 2 mm

measured at the osseous crest; and atraumatic man-

agement of the tissue intraoperatively.

The surgical procedure starts with initial buccal

intrasulcular incisions extending one to two teeth on

either side of the defect. Vertical releasing incisions

are made to facilitate flap reflection. Full-thickness

flap reflection is made at the level of the mucogingi-

val junction, except in the area adjacent the inter-

proximal defect. No attempt is made to reflect the

interproximal tissue at this stage. Palatal incisions

are made that create the papillary triangle and the

palatal flap. Intrasulcular interproximal incisions are

made with great care not to sever the isthmus of

tissue that connects the papillary triangle to the buc-

cal flap. Full-thickness elevation of the papillary tri-

angle is performed using small periosteal elevators.

From the palatal aspect, the isthmus of interproxi-

mal tissues is carefully released from the interproxi-

mal alveolar defect using the back hand of a large

surgical curette. Before the papillary triangle is dis-placed under the contact point, the buccal flap is

examined for any adhesion to the alveolar crest in

the area of the defect. To facilitate coronal repo-

sitioning of the flap and passive closure, the buccal

flap is released from the periosteum with split thick-

ness dissection. The defect is debrided thoroughly. A

decalcified freeze-dried allograft is placed into the

defect and over the alveolar crest in an attempt to

maintain space. The barrier is shaped and sized so

that it will remain passively in position over the de-


18/29


Fig. 59. The crestal incision. Maxillary right cuspid at

baseline. The defect was located on the distal aspect.

Fig. 60. The crestal incision. A crestal incision and distal

vertical releasing incisions uncovered a one-, two- and

three-wall combination intrabony defect.

fect. No suturing of the barrier is performed. The

papillary triangle is returned to its original position

by gently pushing the papillary triangle under the

contact area. The flaps are sutured using a modified

vertical mattress suture. The suture first passes

through the buccal flap and exits the tissue at the

edge of the papillary triangle. The suture overlays the

mesial aspect of the papillary triangle, and the

needle is passed in a mesial to distal direction

through the mesial portion of the palatal flap engag-ing the tip of the papillary triangle, and then is

passed through the distal portion of the palatal flap.

The suture exits the palatal flap at this point and will

overlay the distal aspect of the papillary triangle. The

suture is then passed under the contact area and tied

to the free end of the suture on the buccal flap. The

other areas of the flap are closed in a standard man-

ner using interrupted sutures.

The author reports an average clinical attachment

level gain of 4.71.4 mm after 1 year in a population

121

of 12 defects. Primary closure was obtained in 95%

of the cases. This technique can be applied only to

defects located in the upper jaw, preferably bicus-

pids, with an interdental space wide at least 2 mm.

The crestal incision

When a defect is located at a tooth side adjacent toan edentulous area (frequently occurring to abut-

ment teeth), a crestal incision is performed to access

the area (34, 88). The incision extends 2 to 3 mm

further from the defect and can be associated with

vertical releasing incisions. Full-thickness buccal

and lingual flaps are elevated, the defect debrided

and a membrane positioned. Membrane coverage

and primary closure of the flap over the implanted

material is achieved with interrupted or mattress su-

tures (Fig. 5967).

Fig. 61. The crestal incision. Filling material was posi-

tioned into the defect to support the bioresorbable barrier

membrane.

Fig. 62. The crestal incision. A bioresorbable barrier was

positioned.


19/29


Fig. 63. The crestal incision. Primary closure was obtained

over the membrane.

Fig. 64. The crestal incision. The primary closure was

maintained over time.

Fig. 65. The crestal incision. One-year clinical appearance

of the treated area.

Free gingival graft at membrane removal

The use of free gingival grafts has been proposed to

afford better coverage and protection of the regener-

122

ated interproximal tissues after membrane removal,

when the occurrence of a dehiscence of the gingival

flap does not allow a primary coverage of the inter-

dental area (24). The free gingival graft is positioned

in the interdental space to cover the interproximal

regenerated tissue (Fig. 6876). The gingival graft

consists of an interproximal, saddle-shaped epi-

thelialconnective tissue portion and two disepi-thelialized buccal and lingual portions. The buccal

and lingual connective tissue portions of the grafts

Fig. 66. The crestal incision. Baseline radiograph.

Fig. 67. The crestal incision. One-year radiograph.


20/29


Fig. 68. Free gingival graft. Mandibular Fig. 69. Free gingival graft. The intra- Fig. 70. Free gingival graft. A nonre-

right cuspid at baseline. The defect bony component of the three-wall de- sorbable barrier membrane was posi-

was positioned on the distal side. fect was 5 mm. tioned.

Fig. 71. Free gingival graft. Exposure of Fig. 72. Free gingival graft. The regen- Fig. 73. Free gingival graft. A saddle-

the barrier occurred at week 4. erated tissue at membrane removal shaped free gingival graft was posi-(week 5) was slightly inflamed. tioned in the interproximal space to

protect the regenerated tissue.

extend 2 to 3 mm below the margin of the residual

buccal and lingual flaps. The graft has to be firmly

stabilized with interrupted sutures placed between

the margins of the graft and the buccal and lingual

margins of the gingival flaps. Compressive sutures

are also positioned to improve stability.

123

A randomized controlled clinical trial (24) resulted

in significantly greater probing attachment level

gains in the 14 sites where a free gingival graft was

positioned to cover the regenerated tissues, after

membrane removal (52.1 mm) compared with the

14 sites where a conventional protection of the re-


21/29


Fig. 74. Free gingival graft. At 1 year, the probing depth

was 3 mm.

generated tissue was afforded with coronal posi-

tioning of the gingival flap (3.72.1 mm). In 12 of

the 14 grafted sites the free gingival graft succeeded;

in the other 2 it was lost.

Postoperative regime

The postoperative regime prescribed to patients is

aimed at controlling wound infection or contami-

nation as well as mechanical trauma to the treated

sites (27, 31, 39, 55, 84). It generally includes the pre-

scription of systemic antibiotics (tetracycline or

amoxicillin) in the immediate postoperative period

(1 week), 0.2 or 0.12% chlorhexidine mouthrinsing

two or three times per day and weekly professional

tooth cleaning until the membrane is in place. Pro-

fessional tooth cleaning consists of supragingival

prophylaxis with a rubber cup and chlorhexidine gel.

Patients are generally advised not to perform mech-anical oral hygiene and not to chew in the treated

area. Nonresorbable membranes are removed 4 to 6

weeks after placement, following elevation of partial

thickness flaps. Patients are re-instructed to rinse

two or three times per day with chlorhexidine, not

to perform mechanical oral hygiene and not to chew

in the treated area for 3 to 4 weeks. In this period,

weekly professional control and prophylaxis are rec-

ommended. When bioresorbable membrane are

used, the period of tight infection control regime is

124

extended for 6 to 8 weeks. After this period, patients

are re-instructed to gradually resume mechanical

oral hygiene, including interdental cleaning, and to

discontinue chlorhexidine. Patients are then enrolled

in a periodontal care program on a monthly basis

until 1 year. Probing or deep scaling in the treated

area is generally avoided before the 1-year follow-up

visit.

Fig. 75. Free gingival graft. Baseline radiograph.

Fig. 76. Free gingival graft. One-year radiograph showing

the complete resolution of the defect.


22/29


Barrier membranes

Nonresorbable and bioresorbable barrier mem-

branes are available. The main clinical difference

among the two types is the need of a second surgery

to remove the nonresorbable barrier membranes.

Among the latter, the expanded polytetrafluorethy-

lene membranes are widely used and successfullytested in many clinical studies (Table 1). The ti-

tanium-reinforced membrane is an evolution of the

expanded polytetrafluoroethylene barrier. The de-

sign of this barrier enhances its ability to save space

for regeneration and to support the gingival tissues.

In recent years bioresorbable barrier membranes

have been introduced in guided tissue regeneration

to avoid further surgery. Barrier membranes of colla-

gen (Table 1) and of polylactic acid or copolymers of

polylactic acid and polyglycolic acid (Table 1) have

been evaluated in independent studies, with various

degrees of clinical success. From a clinical stand-point, these membranes are generally easy to ma-

nipulate and position about the defect, but have a

limited ability to save room for regeneration and to

support the gingival tissues.

A subset analysis performed on the studies listed in

table 1 to compare the 351 sites treated with non-re-

sorbable barriers and the 592 treated with bioresorb-

able ones shows probing attachment gains of 3.71.8

mm (95% confidence interval 3.4 to 4.0 mm) for the

nonresorbable group and probing attachment gains

of 3.61.5 mm (95% confidence interval 3.4 to 3.8

mm) for the bioresorbable one. When the bioresorb-

able group is further subdivided into two subgroups,

one for collagen material, the other for polymers, the

weighted mean in terms of probing attachment gain

is 3.01.7 mm (95% confidence interval 2.5 to 3.5

mm) for the 139 collagen-treated sites, and 4.11.6

(95% confidence interval 3.9 to 4.4 mm) for the 453

sites treated with polymers. These data seem to indi-

cate that similar outcomes can be expected using

nonresorbable and bioresorbable barriers. Among the

bioresorbable membranes, however, better outcomes

are to be expected using polymers.

Combination treatment

Schallhorn & McClain have suggested that a combi-

nation therapy consisting of barrier membranes plus

bone grafting may result in significant improvements

of expected outcomes (60, 76). Four studies (16, 52, 53,

63), however, evaluating the added benefit of bone or

bone substitutes used in combination with barrier

125

membranes failed to demonstrate an additive effect

of these adjunctive materials to barrier membranes

alone in deep intrabony defects. On the other hand,

negative effects of the employed materials have not

been reported, indicating a possible use of these ma-

terials in combination with barrier membranes with

the aim of providing better support to the flap and to

save room for regeneration (Fig. 5967). The designandthe samplesize of thecited studies, however, does

not allow any negative effect of the implanted ma-

terials on the guided tissue regeneration process to be

excluded, thereby preventing definitive conclusions.

Complications

Complication of guided tissue regeneration pro-

cedures are frequent and frequently associated with

impairment of the clinical outcomes. Membrane ex-

posure hasbeen reportedin many investigations to bethemajorcomplication with a prevalence in therange

of 70 to 80% (7, 22, 31, 36, 37, 65, 78). Prevalence of

membrane exposure has been highly reduced with

the use of access flaps (modified papilla preservation

technique, interproximal tissue maintenance and

simplified papilla preservation flap) specifically de-

signed to preserve the interdental tissues (25, 29, 30,

67, 84). Control of membrane exposure is of great im-

portance for the clinical outcomes, since in many

studies exposed membranes have been shown to be

contaminated with bacteria (36, 37, 47, 58, 64, 6870,

77, 79, 83). Contamination of exposed nonresorbable

and resorbable barrier membranes has been associ-

ated with reduced probing attachment gains in intra-

bony defects (36, 37, 69, 70, 77).

Other postoperative complications such as swell-

ing, erythema, suppuration, sloughing or perforation

of the flap, membrane exfoliation and postoperative

pain have been reported in independent studies. An

investigation reported the prevalence of pain (16%

of cases), suppuration (11%), swelling and sloughing

of the marginal portion of the flap (7%) in the im-

mediate postoperative period (65, 66). Postsurgicalpain can be easily controlled with administration of

pain-killers. The events connected with local bac-

terial contamination are treated by enhancing the

infection control regime both at home and in the

dental office. This is based on the use of chlorhex-

idine rinses and gels, wiping devices such as soft

toothbrushes and cotton pellets and frequent pro-

fessional cleaning and prophylaxis. Perforation of

the flap or severe exposure of the membrane could

require removal of the material.


23/29


Fig. 77. Decision tree 1: selection of patient, defect and objective of treatment.

Treatment strategies

Guided tissue regeneration in the year 2000 can no

longer be considered as a single treatment approach.

In fact, today there is evidence to consider guided

tissue regeneration as a multifactorial treatment ap-

proach comprising careful selection of patients and

Fig. 78. Decision tree 1, node 1: selection of patient.

Source: modified from Cortellini & Bowers. Int J Peri-

odontics Restorative Dent 1995. FMPS: full-mouth plaque

score. FMBS: full-mouth bleeding score.

126

defects, different surgical techniques, various types

of membranes and adjunctive materials and many

suturing approaches. All the cited components could

be variously combined to build up different treat-

ment strategies loaded with different degrees of

technical difficulties. Various combinations of fac-

tors are expected to produce different clinical results.

The treatment philosophy proposed in this chap-

ter is based on selecting the combination of factors

able to guarantee the maximum degree of predict-

Fig. 79. Decision tree 1, node 2: selection of defect. Source:

modified from Cortellini & Bowers. Int J Periodontics Re-

storative Dent 1995.


24/29


Fig. 80. Decision tree 2: non-aesthetically sensitive sites. modified papilla preservation technique. ITM: interproxi-

The objective of treatment is to increase the periodontal mal tissue maintenance. SPPF: simplified papilla preser-

support and decrease the probing pocket depth. MPPT: vation flap. e-PTFE: expanded polytetrafluoroethylene.

ability with the minimal degree of technical diffi-

culty, to reach the desirable objective of the treat-

ment.

With this in mind, three operative decision trees,

based on a stepwise approach with subsequent de-

cision nodes, have been built up to assist clinicians

in the process of selecting the proper treatment

strategy in different clinical cases. A first decision

tree (decision tree 1) will help clinicians in selecting

patients, defects and setting the objectives of treat-

ment. Then, two different trees, one for non-aesthet-

ically sensitive sites (decision tree 2) and the other

for aesthetically sensitive sites (decision tree 3), willhelp clinicians in selecting the treatment strategy.

The starting-point of the decision process is the

selection of the patient (decision tree 1, node 1; see

paragraph the patient). According to the evidence,

patients with less than 15% of sites presenting with

plaque and residual infection, nonsmokers, with a

high degree of compliance, and systemically healthy

are the best candidates for guided tissue regenera-

tion.

The second step is the selection of the defect (de-

127

cision tree 1, node 2; see paragraph the defect).

Defects presenting with a radiographic angle of 25

or less, an intrabony component deeper than 3 mm

and gingival tissues at least 1 mm thick have the

greatest chances to result in consistent amounts of

clinical attachment and bone gains, irrespective of

the number of residual bony walls. The thickness of

the gingival tissues, if unfavorable, can be improved

with mucogingival surgery.

The third step sets the objectives of the treatment

(decision tree 1, node 3). The primary outcomes and

desirable clinical results of the regenerative treat-

ment of intrabony defects are (i) gain of clinicalattachment and bone, (ii) fill of the intrabony com-

ponent of the defect, (iii) reduction of pocket depth

and (iv) minimal gingival recession. In some in-

stances, however, such as in non-aesthetically sensi-

tive sites, a partial result could be the desirable ob-

jective of treatment if combined with a more simple

and less invasive approach. The main objective of

treatment will be the gain of periodontal support

and the reduction of pocket depth, with a minor in-

terest for the complete resolution of the defect and


25/29


Fig. 81. Decision tree 3: aesthetically sensitive sites. The vation technique. ITM: interproximal tissue maintenance.

objective of treatment is to completely resolve the defect SPPF: simplified papilla preservation flap. e-PTFE: ex-

and minimize recession. MPPT: modified papilla preser- panded polytetrafluoroethylene.

the amount of gingival recession. In aesthetically

sensitive sites, on the contrary, it is desirable to max-

imize the clinical result. The objective of treatment

is to gain periodontal support and reduce pocket

depth associated with full resolution of the intrabony

component of the defect and minimal or no gingival

recession. In the first case (non-aesthetically sensi-

tive sites), less invasive and easier techniques, even

though less efficacious, may be chosen, whereas in

the second case the most effective procedures and

combination of materials will be included in the

treatment strategy, even if associated with greattechnical difficulty.

Once the objectives of treatment have been set,

the next steps are the selection of (i) the surgical ac-

cess of the interproximal defect-associated papilla,

(ii) the type of membrane and the possible use of

filling materials, (iii) the suturing approach to obtain

primary closure of the flap, and (iv) the modality of

protection of the regenerated tissues at the time of

nonresorbable membrane removal. All these de-

cisions are based on anatomical considerations.

128

Non-aesthetically sensitive sites (decision tree 2)

The interdental space can be accessed (node 1) with

a modified papilla preservation technique (25) when

the interdental space is wider than 2 mm at soft

tissue level. A possible alternative is the interdental

tissue maintenance (67), applicable only on upper

premolars. When the interdental width is 2 mm or

less, the treatment of choice is a simplified papilla

preservation flap (30).

Selection of the barrier membrane (node 2) is

based mainly on the anatomy of the intrabony de-fect. Wide defects (ample radiographic angle) and/

or nonsupportive anatomy (one- and two-wall con-

figurations) require the use of stiff membranes or the

combined use of supportive or filling materials.

Among the different commercial proposals, nonre-

sorbable barrier membranes are stiffer than biore-

sorbable ones and therefore are the first choice. The

use of bioresorbable membranes, which render the

procedure easier and less invasive for the patient (1

surgery only), could be associated with the use of


26/29


fillers to avoid its collapse. The ideal material for use

in combination with membranes, however, is far

from being established. Narrow and/or supportive

defects (3 wall configurations) indicate the use of bi-

oresorbable barrier membranes.

The suturing approach (node 3) will be chosen ac-

cording to the defect anatomy and the type of mem-

brane or combination material used in the givencase. In every instance, however, a combination of 2

sutures, one to relieve the tension, the other to close

the flap, are strongly suggested. When a supportive

defect or a supported membrane is the case, suture

of the interdental space can be attempted with an

internal horizontal crossed mattress suture (25) to

relieve the tension. If a non-supported membrane or

a non-supportive defect is the case, an offset internal

mattress suture (30) will be chosen, to limit the api-

cal displacement of the barrier and the consequent

reduction of the space for regeneration. Primary clo-

sure of the interdental space will be attempted inboth the instances with a single passing suture when

the papilla is very narrow; with two parallel passing

sutures when the papilla is wider; or with a mattress

suture (54) to get the best apposition of the flap

edges.

When nonresorbable barrier membranes are used,

the regenerated tissue needs to be protected at the

time of membrane removal (node 4). If the gingiva

has not been impaired by a dehiscence, a replace-

ment flap is the first choice. In case of gingival dehis-

cence, the use of a saddle-shaped free gingival graft

will allow proper protection of the delicate regener-

ated tissues (24).

Aesthetically sensitive sites (decision tree 3)

When the interdental space is wider than 2 mm, it

can be accessed (node 1) with a modified papilla

preservation technique (25) or with the interdental

tissue maintenance (67) on upper premolars only.

When the interdental width is 2 mm or less, the

treatment of choice is a simplified papilla preser-

vation flap (30).For the selection of the barrier membrane (node

2) it is important to consider not only the intrabony

component of the defect, but also the suprabony

component. When the defect has a consistent supra-

bony component, the material of choice is a ti-

tanium-reinforced expanded polytetrafluoroethy-

lene membrane that can properly support the soft

tissues, limiting the gingival recession and, thereby,

preventing aesthetic damages. In fact, the use of ti-

tanium-reinforced expanded polytetrafluoroethy-

129

lene membranes has been reported to result in clin-

ical attachment level gains in the supracrestal por-

tion of the defects (27). When the defect is purely

intrabony, if it is a wide (ample radiographic angle)

and/or a nonsupportive defect (one- and two-wall

configurations), a titanium-reinforced expanded po-

lytetrafluoroethylene membrane is again the first

choice. When the defect is narrow and/or has a sup-portive anatomy (three-wall configurations), biore-

sorbable membranes, eventually associated with

supportive materials (bone or bone substitutes), can

be successfully applied.

The suturing approach (node 3) will be chosen ac-

cording to the defect anatomy and the type of mem-

brane or combination material used in a given case.

A combination of two sutures, one to relieve the ten-

sion, the other to close the flap are mandatory. A

supportive defect (three-wall defect), a self-support-

ing membrane (titanium-reinforced expanded poly-

tetrafluoroethylene membrane) or a supportedmembrane (combination therapy) requires suturing

the interdental space with an internal horizontal

crossed mattress suture (25) to relieve the tension. If

a nonsupported membrane (bioresorbable material)

or a nonsupportive defect (one- or two-wall defect)

is the case, an offset internal mattress suture (30) will

be chosen. Primary closure of the interdental space

will be attempted in both the instances with a single

passing suture when the papilla is very narrow; with

two parallel passing sutures when the papilla is

wider; with an internal mattress suture or with an

internal mattress suture (54) to get the best appo-

sition of the flap edges.

When nonresorbable barrier membranes are used

at the time of membrane removal (node 4), the re-

generated tissues can be protected with a replace-

ment flap in case of gingival integrity or with a

saddle-shaped free gingival graft in case of gingival

dehiscence (24).

Conclusions

Evidence demonstrates a clear benefit from the use

of barrier membranes in the treatment of intrabony

defects. The clinical outcomes, in terms of gain of

periodontal support, pocket depth reduction and

minimal recession of the gingival margin, are influ-

enced by a series of factors that can be controlled, at

least in part. Control of these factors is of paramount

importance to enhance the predictability of guided

tissue regeneration treatment. Clinicians should

carefully select patients and defects, set the objec-


27/29


tives of treatment and then design the surgical strat-

egy. Several surgical alternatives and different ma-

terials can be variously combined to optimize the

treatment strategy. The decision-making process

should be undertaken while keeping in mind the

ratio between the difficulties of the selected pro-

cedures and the expected outcomes. A good balance

between these two components will be the key tosuccess.

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