Denis CecchinatoEriberto A. BressanMarco ToiaMauricio G. AraujoBirgitta LiljenbergJan Lindhe

Osseointegration in periodontitissusceptible individuals

Authors affiliations:Denis Cecchinato, Institute Franci, Padova, ItalyEriberto A. Bressan, Department of Periodontology,University of Padova, Padova, ItalyMarco Toia, Institute Franci, Padova, ItalyMauricio G. Araujo, Department of Dentistry, StateUniversity of Maringa, Maringa, BrazilBirgitta Liljenberg, Jan Lindhe, Department ofPeriodontology, Sahlgrenska Academy at Universityof Gothenburg, Goteborg, Sweden

Corresponding author:M. G. AraujoRua Silva Jardim, 15/sala 0387013-010Maringa-Parana, BrazilTel/Fax: +55 44 3224 6444e-mail: odomar@hotmail.com

Key words: bone implant interactions, clinical research, clinical trials, morphometric analysis

Abstract

Objectives: The aim of the present study was to examine tissue integration of implants placed (i)

in subjects who had lost teeth because of advanced periodontal disease or for other reasons, (ii) in

the posterior maxilla exhibiting varying amounts of mineralized bone.

Material and methods: Thirty-six subjects were enrolled; 19 had lost teeth because of advanced

periodontitis (group P) while the remaining 17 subjects had suffered tooth loss from other reasons

(group NP). As part of site preparation for implant placement, a 3 mm trephine drill was used to

remove one or more 2 mm wide and 56 mm long block of hard tissue [biopsy site; Lindhe et al.

(2011). Clinical of Oral Implants Research, DOI: 10.1111/j.1600-0501.2011.02205.x]. Lateral to the

biopsy site a twist drill (diameter 2 mm) was used to prepare the hard tissue in the posterior

maxilla for the placement of a screw-shaped, self-tapping micro-implant (implant site). The

implants used were 5 mm long, had a diameter of 2.2 mm. After 3 months of healing, the micro-

implants with surrounding hard tissue cores were retrieved using a trephine drill. The tissue was

processed for ground sectioning. The blocks were cut parallel to the long axis of the implant and

reduced to a thickness of about 20 lm and stained in toluidine blue. The percentage of (i) implant

surface that was in contact with mineralized bone as well as (ii) the amount of bone present

within the threads of the micro-implants (percentage bone area) was determined.

Results: Healing including hard tissue formation around implants placed in the posterior maxilla

was similar in periodontitis susceptible and non-susceptible subjects. Thus, the degree of bone-to-

implant contact (about 59%) as well as the amount of mineralized bone within threads of the

micro-implant (about 4550%) was similar in the two groups of subjects. Pearsons coefficient

disclosed that there was a weak negative correlation (0.49; P < 0.05) between volume of fibroustissue (biopsy sites) and the length of bone to implant contact (BIC) while there was a weak

positive correlation (0.51; P < 0.05) between the volume of bone marrow and BIC.

Osseointegrated titanium implants are fre-

quently used as abutments for various fixed

or removable reconstructions in prosthetic

dentistry. Although this kind of treatment is

remarkably successful, both early and late

failures occur (for review see Tomasi et al.

2008). An early failure indicates, according to

Friberg et al. (1991) that e.g. (i) surgical errors

and complications were encountered during

the placement of the implants, (ii) bone

defects with buccal or lingual concavities

were present at the recipient site or (iii) that

healing of the ridge after tooth extraction had

occurred with fibrous rather than bone tissue

formation.

Less than 3% of all implants (for review

see Berglundh et al. 2002; Tomasi et al. 2008)

fail to integrate with the host bone during

healing following surgical placement. In a

study comprising 4641 implants, it was

observed [Friberg et al. (1991)] that jaws with

advanced resorption (groups D and E; Lek-

holm & Zarb 1985) and with soft bone (group

4; Lekholm & Zarb 1985) of the maxillae pre-

sented the highest rates of early implant fail-

ures.

The composition of the bone tissue of the

edentulous ridge of the posterior maxilla of

human volunteers was recently described

(Lindhe et al. 2011). The harvested tissue

exhibited pronounced inter- as well as intra-

individual variation but was comprised of a

mixture of lamellar bone (47%) and woven

bone (8%), osteoid (4%), bone marrow (16%)

Date:Accepted 3 July 2011

To cite this article:Cecchinato D, Bressan EA, Toia M, Araujo MG, Liljenberg B,Lindhe J. Osseointegration in periodontitis susceptibleindividuals.Clin. Oral Impl. Res. 23, 2012, 14doi: 10.1111/j.1600-0501.2011.02293.x

2011 John Wiley & Sons A/S 1

and fibrous tissue (13%). There was no appar-

ent difference between the tissue harvested

from periodontitis and non-periodontitis sub-

jects.

The aim of the present study was to exam-

ine tissue integration of implants placed (i) in

subjects who had lost teeth because of

advanced periodontal disease or for other rea-

sons, (ii) in the posterior maxilla exhibiting

varying amounts of mineralized bone.

Material and methods

The regional ethics committee at the Univer-

sity Hospital, Padova, Italy, approved the

study. Forty-nine partially dentate subjects

with fully healed edentulous portions (Ham-

merle et al. 2004) in the posterior maxilla

(position 1417 and 2427) and scheduled for

implant-supported restorations were recruited

in three different centers. The removal of the

tooth/teeth in the region had occurred at

least 46 months prior to the initiation of

the present study.

The subject sample was described in a pre-

vious publication as well as inclusion and

exclusion criteria (Lindhe et al. 2011). Thir-

teen of the originally recruited subjects were

for different reasons not enrolled in the

study. Of the 36 enrolled subjects, 19 had

lost teeth because of advanced periodontitis

(group P) while the remaining 17 subjects

had suffered tooth loss from other reasons

(group NP). Prior to implant surgery,

informed consent for placement and removal

of the micro-implants was obtained from

each patient.

The patients were treated under local

anaesthesia. Buccal and palatal full thickness

flaps were elevated to expose the bone of the

alveolar ridge. As part of site preparation for

implant placement, a 3 mm trephine drill

was used to remove one or more 2 mm wide

and 56 mm long block of hard tissue (biopsy

site; for details see Lindhe et al. 2011). Hard

tissue preparation was continued according

to the manual for the Astra Tech System

and one or more standard implants (Astra

Tech System; Astra Tech, Molndal, Swe-

den) were installed and cover screw(s) placed.

Lateral (mesial or distal) to the biopsy site,

a twist drill (diameter 2 mm) was used to

prepare the hard tissue for the placement of a

specially designed and custom-manufactured

screw shaped, self-tapping micro-implant

with an Osseospeed surface (Astra Tech)

(implant site). The micro-implants used were

5 mm long, had a diameter of 2.2 mm and

were at all sites fully submerged in the bone

tissue of the ridge. A cover screw was placed

on the implant device. The flaps were

replaced and closed with interrupted sutures

that were removed after 10 days.

After 3 months of healing, i.e. at the time

for the second stage surgery at the standard

implants, minute full thickness flaps were

elevated. The micro-implants with surround-

ing hard tissue cores were retrieved using a

trephine drill (internal diameter 3.4 mm,

external diameter 4.0 mm). The flaps were

replaced and secured with interrupted sutures

that were removed after 10 days.

Abutments were placed on the standard

implants and the restorative procedure was

initiated.

The samples from the biopsy sites were

decalcified, dehydrated, and embedded in par-

affin (for details see Lindhe et al. 2011). Serial

sections were prepared parallel with the long

axis and from the central portion of the har-

vested tissue cylinder. The microtome was

set at 5 lm. Sections were stained in haemat-

oxylin and eosin or Movat pentachrome.

The biopsies from the implant sites were

placed in a fixative containing a 4% buffered

formalin solution and were processed for

ground sectioning according to methods

described by Donath & Breuner (1982) and

Donath (1988). The samples (blocks) were

dehydrated in increasing grades of ethanol

and infiltrated with Technovit 7200 VLC-

resin (Kulzer, Friedrichrsdorf, Germany),

polymerized and sectioned using a saw

microtome (Leica SP 1600; Leica, Nussloch,

Germany).

The blocks that were cut parallel to the

long axis of the implant were reduced to a

thickness of about 20 lm by microgrinding

and polishing and stained in toluidine blue.

The percentage of (i) implant surface that

was in contact with mineralized bone as well

as (ii) the amount of bone present within the

threads of the micro-implants (percentage

bone area) was determined according to Jen-

sen & Sennerby (1998). The measurements

were performed in a Leitz DM-RBE micro-

scope (Leica, Wetzlar, Germany) equipped

with an image system (Q-500 MC; Leica).

ANOVA was used to assess differences

between data obtained from samples repre-

senting periodontitis and non-periodontitis

subjects. The subject was used as the statisti-

cal unit. Values of P < 0.05 were accepted as

being statistically significant. Pearsons coef-

ficient of correlation was calculated to assess

whether the amount of (i) mineralized bone,

(ii) bone marrow, (iii) fibrous tissue deter-

mined in the biopsy samples influenced the

degree of bone to implant contact (BIC) and

amount of mineralized bone within threads

(B-area) were measured in the ground sec-

tions from implant sites.

Results

The protocol used in the current clinical

study did not delay the upcoming restorative

procedure and no complications from adja-

cent sites harbouring the standard implant(s)

were reported.

The tissues from the biopsy sites were

comprised of a mixture of mineralized bone

(including lamellar and woven bone), osteoid,

bone marrow, and fibrous tissue. The overall

tissue build up of the biopsy sites is

presented in Table 1 (from Lindhe et al.

2011) as well as findings from periodonti-

tis susceptible and non-susceptible subjects.

Mineralized bone (lamellar and woven

bone) made up 55.1 11.1% (group P =

54.6 11%, group NP = 55.8 11.5%) of the

tissue volume while bone marrow occupied

16.5 10.4% (group P = 17.4 11.6%, group

NP = 15.4 8.8%) and fibrous tissue

12.8 8.9% (group P = 12.6 10.7, group

NP = 12.9 6.3%).

At the time of retrieval surgery all micro-

implants were clinically stable. Eight of the

implant site specimens were discarded for

different technical reasons. The ground sec-

tions consisted of a central region that

included the titanium screw lateral of which

varying amounts of tissue were present. The

Table 1. Percentage distribution (%) of various tissue elements in the biopsy sites (data fromLindhe et al. 2011)

Total sample (n = 36) Group P (n = 19) Group NP (n = 17)

Mineralized bone(LB+WB) 55.1 11.0 54.6 11 55.8 11.5Bone marrow 16.5 10.4 17.4 11.6 15.4 8.8LB+WB+osteoid 59.4 12.3 58.4 13.0 60.6 11.5Fibrous tissue 12.8 8.9 12.6 10.7 12.9 6.3

Values are mean standard deviation.Group P, periodontitis susceptible subjects; group NP, non-periodontitis susceptible subjects;LB, lamellar bone; WB, woven bone.

2 | Clin. Oral Impl. Res. 23, 2012 / 14 2011 John Wiley & Sons A/S

Cecchinato et al Osseointegration in periodontitis

bone tissue was comprised mainly of lamel-

lar bone. The soft tissue had morphological

features characteristic of either bone marrow

or loose connective tissue (Fig. 1).

The hard tissue present within the threads

of the micro-implants and close to the rough

surface of the titanium device was comprised

of lamellar bone and at some sites a mixture

of lamellar and woven bone (Fig. 2). The min-

eralized tissue or bone marrow appeared in

all sections to be in direct contact with the

surface of the micro-implant.

There was no apparent difference between

the tissue surrounding implants retrieved

from patients in groups P and NP. The degree

of bone to implant contact (Table 2; BIC%)

was 58.6 12.9% (group P = 59.6 13.3%,

group NP = 57.2 13.5%). No significant dif-

ference was observed between the groups

with respect to BIC%.

The percentage of mineralized bone within

the implant threads (Table 2; B-area) was

47.5 15.2% (group P = 49.5 16.3, group

NP = 44.7 13.9%). No significant difference

was observed between implants retrieved from

periodontitis susceptible and non-susceptible

subjects with respect to B-area.

Pearsons coefficient disclosed that there

was a weak negative correlation (0.56;P < 0.05) between volume of fibrous tissue

(biopsy sites) and the length of bone to

implant contact (BIC) while there was a cor-

responding weak positive correlation (0.57;

P < 0.05) between the volume of bone mar-

row and BIC. There was no significant corre-

lation between amount of mineralized bone

(lamellar + woven bone) present in the

biopsy sites and the degree of BIC or B-area

determined in the implant sites.

Discussion

In this clinical-histological study it was

observed that the placement and retrieval of

micro-implants in the posterior maxilla of

human volunteers could be performed with-

out jeopardizing healing of standard screw-

type implants. This is an agreement with

conclusions previously presented (e.g. Jensen

& Sennerby 1998; Ivanoff et al. 2001; Hall-

man et al. 2002; Lindgren et al. 2009) from

similar studies.

In the current sample close to 60% of the

surface of the micro-implants was found to

be in contact with mineralized bone (BIC).

This indicates that the micro-implants at

the time of implant retrieval were properly

osseointegrated. This high percentage of BIC

that had been established already after

3 months of healing furthermore documents

that the surface of the micro-implants had

excellent osteoconductive properties. This

conclusion is in agreement with observa-

tions from experiments using various animal

and in vitro models (e.g. Ellingsen 1995;

Berglundh et al. 2007; Isa et al. 2006; Thor

et al. 2007).

The main finding of the present study was

that healing including hard tissue formation

around implants placed in the posterior max-

illa apparently was similar in periodontitis

susceptible and non-susceptible subjects.

Thus, after 3 months of submerged healing,

neither the degree of bone-to-implant contact

(BIC) nor the amount of mineralized bone

within threads (B-area) of the micro-implant

differed between the two groups of subjects.

It is well known that cells that repopulate

post-extraction sockets determine the quality

of the tissue formed (Amler 1969; Melcher

1976; Cardaropoli et al. 2003). Thus, provided

cells with a bone forming potential (e.g. peri-

odontal ligament fibroblasts, pericytes, osteo-

blasts) become established in the provisional

matrix, woven bone will form and fill the

socket void. This immature bone will during

remodelling be replaced with lamellar bone

and marrow (Cardaropoli et al. 2003). How-

ever, if during the early phase of healing,

mesenchymal cells originating from the

gingiva or oral mucosa migrate into the

socket (the wound), a fibrous connective

tissue will be established and hard tissue

formation becomes compromised. In the

current biopsy sample fibrous connective

tissue made up about 13% of the total tissue

volume; in six sites >20% of the volume was

made up of a fibroblast and collagen rich con-

nective tissue. The statistical analysis (Pear-

sons correlation coefficient) disclosed that

there was a negative correlation between

amount of fibrous tissue and degree of bone

to implant contact. This means that site

preparation and implant placement in an

alveolar ridge in which large amounts of

fibrous connective tissue are present may

retard (prevent) osseointegration during heal-

ing. In a previous publication (Lindhe et al.

2011) it was reported that the amount of

mineralized bone (lamellar bone and woven

bone) that was present in biopsies sampled

from the posterior maxilla varied consider-

ably; from about 80% to 35%. In the current

analysis it was observed that the amount of

mineralized bone as assessed in the paraffin

sections did not correlate with the degree of

BIC or B-area. This indicates that wound

healing (and associated osseointegration) fol-

lowing site preparation and implant installa-

tion are unrelated to the amount of hard

tissue present at the recipient site.

References

Amler, M.H. (1969) The time sequence of tissue

regeneration in human extraction wounds. Oral

Surgery Oral Medicine and Oral Pathology 27:

309318.

Fig. 1. A photomicrograph illustrating a micro-screw

with surrounding tissue. Most parts of the titanium

device after 3 months of healing were properly inte-

grated in mineralized bone. Toluidine blue stain. Origi-

nal magnification 92.5.

Fig. 2. Higher magnification of the area outlined in

Fig. 1.The tissue present within the threads of the

micro-implants was mainly comprised of lamellar bone.

Toluidine blue stain. Original magnification 910.

Table 2. Amount of bone to implant contact (BIC%) as well as amount of mineralized bone withinthreads (B-area%)

Total sample (n = 28) Group P (n = 16) Group NP (n = 12)

BIC 58.6 13.2% 59.6 13.3% 57.2 13.5%B-area 47.5 15.2% 49.5 16.3% 44.7 13.9%

Values are mean standard deviation.BIC, bone to implant contact%, B-area, mineralized bone within threads; Group P, periodontitissusceptible subjects; group NP, non-periodontitis susceptible subjects.

2011 John Wiley & Sons A/S 3 | Clin. Oral Impl. Res. 23, 2012 / 14

Cecchinato et al Osseointegration in periodontitis

Berglundh, T., Abrahamsson, I., Albouy, J.P. &

Lindhe, J. (2007) Bone healing at implants with a

fluoride-modified surface: an experimental study

in dogs. Clinical Oral Implants Research 18:

147152.

Berglundh, T., Persson, L. & Klinge, B. (2002) A sys-

tematic review of the incidence of biological and

technical complications in implant dentistry

reported in prospective longitudinal studies of at

least 5 years. Journal of Clinical Periodontology

29 (Suppl. 3): 197212; discussion 232233.

Cardaropoli, G., Araujo, M. & Lindhe, J. (2003)

Dynamics of bone tissue formation in tooth

extraction sites. An experimental study in dogs.

Journal of Clinical Periodontology 30: 809818.

Donath, K. (1988) Die Trenn-Dunnschliff-Technik

zur Herstellung histologischer Praparate von

nicht schneidbaren Geweben und Materialen. Der

Praparator 34: 197206.

Donath, K. & Breuner, G. (1982) A method for the

study of undecalcified bones and teeth with

attached soft tissues. The Sage-Schliff (sawing

and grinding) technique. Journal of Oral Pathol-

ogy 11: 318326.

Ellingsen, J.-E. (1995) Pre-treatment of titanium

implants with flouride improves their retention

in bone. Journal of Materials Science. Materials

in Medicine 6: 749753.

Friberg, B., Jemt, T. & Lekholm, U. (1991) Early

failures in 4,641 consecutively placed Branemark

dental implants: a study from stage 1 surgery to

the connection of completed prostheses. The

International Journal of Oral & Maxillofacial

Implants 6: 142146.

Hallman, M., Sennerby, L. & Lundgren, S. (2002) A

clinical and histologic evaluation of implant inte-

gration in the posterior maxilla after sinus floor

augmentation with autogenous bone, bovine

hydroxyapatite, or a 20:80 mixture. The Interna-

tional Journal of Oral & Maxillofacial Implants

17: 635643.

Hammerle, C.H., Chen, S.T. & Wilson, T.G. Jr

(2004) Consensus statements and recommended

clinical procedures regarding the placement of

implants in extraction sockets. The International

Journal of Oral & Maxillofacial Implants 19

(Suppl.): 2628.

Isa, Z.M., Schneider, G.B., Zaharias, R., Seabold, D.

B. & Stanford, C. (2006) Effects of fluoride-modi-

fied titanium surfaces on osteoblast proliferation

and gene expression. The International Journal of

Oral & Maxillofacial Implants 21: 203211.

Ivanoff, C.J., Hallgren, C., Widmark, G., Sennerby,

L. & Wennerberg, A. (2001) Histologic evaluation

of the bone integration of TiO (2) blasted and

turned titanium microimplants in humans. Clini-

cal of Oral Implants Research 12: 128134.

Jensen, O.T. & Sennerby, L. (1998) Histologic analy-

sis of clinically retrieved titanium microimplants

placed in conjunction with maxillary sinus floor

augmentation. The International Journal of Oral

& Maxillofacial Implants 13: 513521.

Lekholm, U. & Zarb, G.A. (1985) Patient selection

and preparation. In: Branemark, P-I., Zarb, G.A.

& Albrektsson, T., eds. Tissue Integrated Prosthe-

ses: Osseointegration in Clinical Dentistry, 199

209. Chicago: Quintessence Publishing.

Lindgren, C., Sennerby, L., Mordenfeld, A. & Hall-

man, M. (2009) Clinical histology of microim-

plants placed in two different biomaterials. The

International Journal of Oral & Maxillofacial

Implants 24: 10931100.

Lindhe, J., Cecchinato, D., Bressan, E.A., Toia, M.,

Araujo, M. & Liljenberg, B. (2011) The alveolar

process of the edentulous maxilla in periodontitis

and non-periodontitis subjects. Clinical of Oral

Implants Research 22: 11681171.

Melcher, A.H. (1976) On the repair potential of

periodontal tissues. Journal of Periodontology 47:

256260.

Thor, A., Rasmusson, L., Wennerberg, A., Thom-

sen, P., Hirsch, J.M., Nilsson, B. & Hong, J.

(2007) The role of whole blood in thrombin gener-

ation in contact with various titanium surfaces.

Biomaterials 28: 966974.

Tomasi, C., Wennstrom, J.L. & Berglundh, T. (2008)

Longevity of teeth and implants a systematic

review. Journal of Oral Rehabilitation 35 (Suppl.

1): 2332.

4 | Clin. Oral Impl. Res. 23, 2012 / 14 2011 John Wiley & Sons A/S

Cecchinato et al Osseointegration in periodontitis