ABSTRACTA 43 year old male patient presented with afractured PFM crown extending subgingi-vally on tooth #21 which was previouslyendodontically treated. #11 was endodonti-cally treated with mobile PFM crown. Afterclinical examination and evaluation of OPGand CBCT, it was indicated that restorabili-ty of both upper central incisors was poor.Therefore it was planned for extraction andfollowed by surgical placement of implant.This case report describes the flapless surgi-cal placement of Zirconia dental implantfor replacing maxillary central incisors. Italso describes the biocompatibility, aesthet-ics and corrosion resistant properties of zir-conium implant.

INTRODUCTIONA dental implant is a prosthesis thatreplaces the root of a natural tooth. Thissmall screw-shaped device is placed into thejawbone. Over time, bone fuses with theimplant to form a solid base. Metal-freedental implants are made of monolithic zir-conia. This means that the implant and theabutment are constructed from one piece ofincredibly strong white ceramic.

Osseointegration of zirconia dentalimplants may be comparable with that oftitanium implants. Studies found that

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Replacing Maxillary Central Incisors by Zirconia Implants

implantology section

HOW KIM CHUAN AND ASHWINI KHOLGADE

FIG 1a: Pre-operative extra-oralphotograph shows missing #11and #21

FIG 3a: Sagittal view CBCT reveals 15.3mm height of the alveolar ridge forimplant placement

FIG 3b: Occlusal view CBCT reveals sufficient bucco- lingual width of thealveolar bone

FIG 2: Pre-operative OPG, endodontically treated #11 and #21 can be seen

FIG 1b: Intra-oral photograph after extraction of #11 and #21

FIG 3: Pre-operative CBCT images

FIG 3c: Frontal CBCT shows close proximity of lateral incisor root to the intendedimplant placement site

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FIG 4: Zeramex Implant System FIG 5a: An initial bone penetration done at #21implant site by using round drill

FIG 5b: Twist drill of 2.2mm diameter used toestablish depth at site of #11

zirconia dental implant have low, well distributed and similar stressdistribution when compared with titanium implants. Furthermore,zirconia particles used for surface modifications of titaniumimplants may have the potential to improve initial bone healing andresistance to removal of torque.

Although fabrication of surface modifications for zirconia is dif-ficult, CO2 lasers revealed distinct surface alterations to zirconiaand additional studies about this technique may help to improvesurface roughness. Coated or surface-modified zirconia implantsshowed higher removal torque values than machined zirconiaimplants. To fulfill biomechanical requirements, restoring zirconiaimplants with high strength ceramics or metal ceramics would bebeneficial.1

CASE REPORT43 years old male patient had chief complaint of fractured crown on#21. Clinical and radiographic evaluation revealed that #11 and #21were endodontically treated (Figure 2). #21 had fractured PFMcrown below the gum-line and #11 had mobile PFM crown. Aftertaking OPG (Figure 2) and CBCT, patient advised that the teeth

(#21 and #11) had poor restorability hence indicated for extraction.

TREATMENT OPTIONS FOR PROSTHESIS WEREOption 1: A 6-unit FPD using teeth #12, #13 and #22, #23 as abut-ments. Option 2: Surgical placement of dental implant for the replacementof the edentulous space at tooth #11 & #21 followed by crown whichwas to be a more conservative option. The pros and cons of eachtreatment option were explained to the patient. Patient decided togo with extraction and implant placement on the basis of long termsuccess rate and preservation of adjacent teeth. The patient had nomedical illness. Pre-operative extra-oral and intra-oral images weretaken taken for diagnostic evaluation. (Figures 1a, 1b)

TREATMENT PLAN1) Extraction of #11 and #21 under local anesthesia.2) Placement of Zeramex dental implant on #11 and #21 after

extraction socket healing.3) Implant site allowed to heal followed by placement of prosthesis.

TREATMENT PROGRESSExtraction of #11 and #21 was done under Local Anesthesia. Theteeth were extracted atraumatically, taking care to preserve as muchof the buccal plate and surrounding bone as possible (Figure 1b).Post extraction instructions were given to the patient and medica-tion were prescribed. Provisional splinted acid etched bridge sup-ported by #13, #12, #22, #23 was given for #11, #21 and patient wasfollowed up.

After extraction site had healed for 8 weeks, implant placementprocedure was carried out.

CBCT (Figure 3) were taken for evaluation of bone quality andheight. The implant osteotomy site was anesthetized with local infil-tration in the area of #11 and #21. Flapless surgery was carried outand Zeramex implant system was used to place dental implants(Figure 4).

A round drill was used to make the initial penetration into bonefor the implant site (Figure 5a). A small twist drill of 2.2mm in diam-eter was marked to indicate various lengths (i.e. Corresponding tothe implant sizes) was used next, to establish the depth and align longaxis of the implant recipient site (Figure 5b). A surgical guide pin wasinserted to ensure proper positioning, and used throughout the pro-cedure to direct the proper implant placement (Figure 6). This was

FIG 6: Guide pin was placed in the osteotomy site of #21 to confirm position andangulation of the osteotomy site

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implantology section

FIG 7a: Twist drill of 2.8mm diameter used to establish depth at #21 implant site FIG 7b: Twist drill of 3.5mm diameter used to establish depth at #11 implant site

FIG 7c: Profile drill of 3.5 mm diameter was used at #11 implant site

FIG 8b: Tap drill of 4.1mm used for non-stress implant fixture torque insertion

FIG 7d: Tap drill of 4.1mm was used to create a nice implant bed so that duringtorque insertion the implant would fit without excessive torque. Hand torque insertion used to prevent building up of heat.

FIG 8a: Profile drill of 3.5mm used for the transmucosal head of theimplant geometry

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followed by 2.8mm and 3.5mm diameter twist drills to prepareosteotomy site (Figures 7a, 7b). Drills were externally and internallyirrigated. The twist drill was used at a speed of approximately 800 to1500 rpm; refrigerated saline was used for copious irrigation to pre-vent overheating of the bone. Drill was intermittently and repeated-ly pumped and pulled out of the osteotomy site while drilling toexpose them to the water coolant and facilitate clearing bone debrisfrom the cutting surfaces. The drills were pumped (up and down)intermittently and avoided a constant “push” of the drill in the api-cal direction only2. 3.5 mm Profile drill (Figure 8a) was used forosteotomy site and tap drill of 4.1 mm (Figure 8b) were used to cre-ate a nice implant bed to achieve good prognosis (Figures 7c, 7d).An implant fixture of 4.1mm body diameter and 12mm height byZeramex was inserted simultaneously at the implant sites of extract-ed #11 and #21 with precise interdental spacing and correct inclina-tion3 (Figure 9). Implants mushroom heads were placed 1mm belowthe alveolar ridge like transmucosal implants for enhanced aesthet-ics (Figure 12b). Excellent primary stability was achieved. Coverscrews were placed and flushed with the rest of the ridge to minimizethe risk of exposure (Figure 10). Intra-oral and extra-oral photo-graphs taken after surgical placement of Zeramex dental implant(Figures 11a, 11b).

An immediate peri-operative OPG (Figure 12a) and CBCT(Figures 13a, 13b) were taken for evaluation. Post-operative

instructions were given to the patient and medicines prescribed.Provisional splinted acid etched bridge supported by #13, #12, #22,#23 was given for #11, #21 (Figure 14). Patient was advised to main-tain good oral hygiene and recalled for reviewing implants to checksigns of infection and implant stability. The healing was uneventful.The surgical site was left undisturbed for 4 months.

Restorative procedure was carried out 4 months after the initialsurgery. Cover screws were removed and implant heads werecleared. Closed tray impression technique was used. Dental analogswere subsequently fitted onto the impression copings and theninserted into PVS impression. The angle corrected zirconium abut-ments were selected and fitted onto the working model. Note thatcarbon fiber internal connection screws were used. It has been seenthat carbon fiber screw is more sturdy and resistant to internalscrew loosening than the titanium screw. Impression was made byusing Impregum “Penta” Soft Polyether Impression Material(Figure 15).4

The case was sent to lab for final fabrication of crowns with biteregistration and shade A2 was selected. Abutments were placed ondental analogs and porcelain fused to zirconium crowns fabricatedonto the zirconium abutments (Figures 16a, 16b). After three weeks,abutments were screwed on #11 and #21 implant (Figure 17),cementation of porcelain fused to zirconia crown was carried out(Figure 18). The crowns were checked for shade, interproximal con-

FIG 9: Zeramex Implant of 4.1mm diameter and 12 mm height were inserted into the prepared osteotomy sites (#11 & #21) with a handpiece followed by hand torque of 30 N cm-1

FIG 10: Cover screws were placed at #11 & #21 and flushed with the rest of the alveolar ridge to minimize the risk of exposure

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implantology section

FIG 11a: Intra-oral photograph

FIG 12a: Peri-operative OPG after Placement of implants

FIG 13a: Implants are placed precisely with correct inclination using flapless surgery. This is shown in both the sagittal and occlusal view in CBCT.

FIG 12b: Transmucosal zirconium implant and bone level titanium implant

FIG 11b: Extra-oral photograph

FIG 11: Zeramex dental implants were placed in the edentulous site of #11 & #21.

FIG 13b: Implants are placed precisely parallel to each other

FIG 14a: Frontal view FIG 14b: Occlusal view

FIG 14: Provisional splinted acid etched bridge supported by #13, #12, #22, #23 was given for #11, #21

FIG 15: Closed tray impression coping were used. Dental analogs were subsequently fitted onto the impression coping and then inserted into the PVS impression.

FIG 16a: Abutments were placed on dental analogs and crowns fabricated on it. FIG 16b: Porcelain fused to zirconium crowns were fabricated onto the zirconiumabutments. From the fixture to abutment to crown including the internal connec-tion screws are all non metallic

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implantology section

FIG 17: Abutment were placed on implant #11, #21. Visual inspection ensures intimate contact between the abutments and the implants

FIG 19: Post-operative extra-oral & intra-oral frontal view shows high aesthetic gingival profile without any metal shadowing. The porcelain fused to zirconium crown alsogives good light refractivity index similar to that of enamel crystal.

FIG 18a: Frontal view FIG 18b: Occlusal view

FIG 18: Porcelain fused to Zirconia Crown were placed on #11 & #21 implant

tacts and occlusion followed by cementation with 3M Rely X resincement (Figure 18). There was a small triangular defect in between#11 and #21 (Figure 18). Patient was reviewed 6 months later tomonitor if this triangular defect would creep up spontaneously.Post-operative extra-oral & intra-oral images were taken (Figure 19).Post-operative OPG was taken for evaluation (Figure 20).

RESULTSEdentulous spaces with 11 and 21 teeth were successfully restoredwith zirconium implants (Figures 19, 20). The entire healing phaseof the implant therapy was uneventful. 4 months after implantplacement the region showed good soft tissue healing and new boneregeneration. Patient was pleased with the outcome and the esthet-ics were restored. The prosthesis remained stable and fully func-tional with good surrounding gingival health.

DISCUSSIONThe use of dental implants in the maxillary anterior region toreplace missing teeth is a viable treatment option. There are manybenefits of fixed dental implant-supported prosthetics versus tradi-tional crown and bridge or removable tooth-borne prosthetics.Maintenance of residual bone, ease of oral hygiene, increasedlongevity, and non-involvement of adjacent teeth are a few advan-tages of using dental implants. In order to provide successful andaesthetic dental implant treatment, certain clinical parameters mustbe met. This is particularly true in the anterior maxilla, where theteeth and their supporting structures are readily visible.5

ADVANTAGES OF METAL-FREE DENTAL IMPLANTS• Biocompatibility – Zirconia integrates with its surroundings, set-tling solidly into bone and encouraging a good seal with gums.There is no risk of allergic reaction, and the implant will not affectsense of taste or temperature sensitivity.

• Aesthetics – It is not unusual to see a gray line at the base of a metaldental implant.While gum recession is unlikely to be triggered bya zirconia implant, should it occur as a part of the aging process,the smile remains white and natural-looking. The tooth coloredabutment lets the porcelain crown restoration retain translucencyfor a bettermatch to adjacent teeth.

• Corrosion resistant – Zirconia is a bio-inert material. It resistschemical corrosion, does not conduct heat or electricity, and doesnot trigger chemical reactions that could have an impact on youroral health or bodily wellness.

• Gum health – The point where a titanium dental implant and theabutment connect is below the gum line. Because one cannotbrush or floss at this depth, that connection point traps bacteriathat contribute to gum disease. The one-piece design of a zirconiaimplant used in this patient extends to the gum line. Hence,patient is able to brush and floss normally for a clean, odor freerestoration.

• Success – The material is strong enough for placement at any areaof the mouth. The overall success rate with zirconia implants is98%.1

CONCLUSIONIn this case report, a successful replacement of maxillary centralincisors by zirconia dental implant using Zeramex implant systemwas seen with uneventful healing. This case shows the advantages ofzirconia dental implant over metal implant. Excellent functionaland esthetic results were achieved.

REFERENCES1) American Academy of Implant Dentistry, journal of oral implan-

tology, Article 374, Vol. XXXVII/No. Three/2011.2) Carranza’s Clinical Periodontology 12th Edition; Michael G.

Newman, Henry Takei, Perry R. Klokkevold; oral implantology732, 733

3) Journal of interdisciplinary Dentistry, Single tooth implants:Pretreatment considerations and pretreatment evaluation, V KShenoy; Article, 2012 vol 2, 149-157

4) Chee W, Jivraj S. Impression techniques for implant dentistry. BrDent J 2006 Article; 201: 429–432.

5) Cordaro L. Implants for restoration of single tooth spaces inareas of high esthetic risk. In: Dawson A, Chen S, Buser D et al,eds. The SAC Classification in Implant Dentistry. QuintessencePublishing, Article, 2009:50-56.

FIG 20: Post-Treatment OPG

Dato’ Dr. How Kim Chuan graduated in Singapore in 1991 and spe-cialised in orthodontics in London in 1993. Dr. How is currently thechief consultant and managing director of Imperial DentalSpecialist Centre in Kuala Lumpur, Malaysia. Dr. How has a numberof post-graduate qualifications in oral surgery, implantology andlaser and aesthetic dentistry. Renowned in the field of orthodon-tics, he has conducted several clinical orthodontic courses inMalaysia, Cambodia, Myanmar, Nigeria and Vietnam. Dr. How is a

Fellow in a number of internationally acclaimed colleges including the Royal College ofSurgeons of England, Royal College of Surgeons of Edinburgh, International College ofDentistry (ICD), World Clinical Laser Institute, World Federation of Laser Dentistry,College of Dental Specialists of Malaysia and the Academy of Medicine. He is also aDiplomate of the International Congress of Oral Implantologists (ICOI).

Dr. Ashwini Kholgade received her Bachelor of Dental SurgeryDegree with First Class Honours from the Sinhgad Dental College& Hospital in Pune, MH, India in 2011. Dr. Kholgade has worked as adental officer in private dental clinics in India.

About the AUTHORS

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