Teeth Realignment for Enhanced Posterior Single Implant Restorations

J Oral Maxillofac Surg 65:40-46, 2007, Suppl 1

Teeth Realignment for Enhanced Posterior Single Implant Restorations Ami Smidt, DMD, MSc, BMedSc,* Eyal Venezia, DMD, MSc, BMedSc,† and Moshik Tandlich, DMD, BMedSc‡ As the use of dental implants became a widespread and acceptable treatment modality, with an overall good long-term prognosis, treatment concepts changed reciprocally. Nowadays, dental implants are considered routine and are preferred over other modalities such as removable or fixed partial dentures or etched cast restorations supported by neighboring teeth. However, we often find clinical situations that challenge the placement of an implant because of insufficient space. Congenitally missing tooth, loss of a tooth because of periodontal disease, long-lasting extracted sites, or lost tooth structures caused by caries or trauma may give rise to teeth drifting and loss of coronal space that may hamper implant placement. Minimal or minor orthodontic procedures may be used to regain adequate space for implant placement. The 3 clinical cases presented in this article discuss the various considerations and the use of teeth as mediators in small scale orthodontic treatment performed to achieve enhanced results for single implant restorations to replace missing teeth. © 2007 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 65:40-46, 2007, Suppl 1 Several restorative alternatives may exist for replacing a missing tooth. Each alternative has its own benefits, but the use of implant-assisted restoration in such events has become widely spread for many good reasons, especially between intact neighboring teeth. Today, it is considered inappropriate, in case of intact teeth, to select porcelain fused to metal bridges as the first choice of treatment. The implant treatment modality is being introduced nowadays as a more conservative approach with good and long term prognosis.1,2 In general, implant placement requires consideration of 3 disciplines in a planned sequence: orthodontics, surgery, and restorative. A successful implant placement procedure depends on the availability of bone, its dimensional volume and quality, the spatial relation between the bone and the occlusal plane, and the recipient site— all of which allow imitation of the actual anatomy of the missing tooth.3 Immediate parameters for evalua-

tion are the mesio-distal distance between the neighboring teeth and the bucco-lingual dimension of the residual ridge. Collapse of posterior teeth usually occurs when spaces are left after extraction of molars and or premolars. Over a period of time, teeth adjacent to edentulous spaces drift and gradually tip into extraction sites.4,5 This situation may present a challenge during surgery, and more during the restorative phase. Orthodontics designed to upright the adjacent tipped teeth serve for the surgical phase and allow an otherwise impossible implant placement. The restorative phase after the procedure is easier and enhances the health of the implant– crown interface and adjacent teeth in all aspects. Planning implant placement demands evaluation of the existing hard and soft tissues and a thorough evaluation of the 3-dimensional space, intra- and interarch-wise. If orthodontics is indicated, it is performed before the surgical phase to ensure correct unlimited implant placement for optimal results. Where teeth movement is required on 1 side of the missing tooth area (mesial or distal), orthodontics may take place after implant placement and integration, providing that the implant site is accessible beforehand. In such a case, the implant may serve as an anchoring device for the orthodontic movement.

Received from the School of Dental Medicine, The Hebrew University–Hadassah, Jerusalem, Israel. *Senior Clinical Lecturer and Head, The Center for Graduate Studies in Prosthodontics. †Clinical Instructor, Department of Periodontics. ‡Clinical Instructor, Department of Periodontics. Address correspondence and reprint requests to Dr Smidt: 6 Levitan Str, Neve Avivim, Tel Aviv, Israel 69204; e-mail: smidta@ md.huji.ac.il

The Space Issue

© 2007 American Association of Oral and Maxillofacial Surgeons

In the event of posterior teeth collapse into a missing tooth area, placing an implant is problematic be-

0278-2391/07/6507-0106$32.00/0 doi:10.1016/j.joms.2007.03.011

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SMIDT, VENEZIA, AND TANDILCH

cause the access to the implant site is interfered with by the clinical crowns of the neighboring teeth and sometimes even by their roots (especially in the anterior area). This is true when replacing 1 missing tooth or where 2 implants are required, especially in a missing first molar area.6 It is imperative to discuss the space requirements for placing an implant. In the anterior area, the space needed for implant-borne restoration can be estimated using the contralateral tooth measurments.7 Another important factor is the occlusion, meaning the intermaxillary distances and relations. A regular implant platform diameter runs approximately 4 mm, which must fit interproximally at the crest of the alveolar ridge leaving at least 1 mm for proper healing and for the developing papilla between the implant crown and neighbor tooth.8 Where this space is limited, a narrower implant and platform should be considered to leave adequate space for the insertion of the implant. Not only the mesio-distal aspect is examined, but also the bucco-palatal dimensions, from the crestal level down to the apical part of the implant site. Meticulous presurgical planning based on a thorough clinical and radiographic evaluation must be completed before performing the procedure. The possible need for hard and soft tissue augmentation should be determined at that time.9 The purpose of this article is to present the role and importance of teeth movement around implants before and after implant placement. A series of 3 cases presented will discuss the role of minor orthodontic movements made to enhance implant-assisted restorations by modifying the edentulous space and minimizing the extent of prosthetic treatment.

Report of Cases ARCH REALIGNMENT FOR TREATMENT PLANNING– CASE 1

A female patient presented to the clinic with a decayed left maxillary second premolar positioned palatal to the arch. The palatal position, the amount of decay, and the loss of crown walls made the molars migrate mesially and as a result the mesio-distal dimensions of the premolar area became reduced. A significant concavity of the buccal plate facing that premolar tooth was present clinically. Examination of the periapical radiograph revealed intimacy between the root of the tooth and the sinus walls, lack of proper interproximal bone on both sides of the tooth, and poor quality of the existing root canal. One of the treatment options discussed was tooth extraction followed by a 3-unit bridge. The implant option considered was questionable because of the reduced mesiodistal dimensions, the buccal deficiency, and the sinus wall proximity (Fig 1).

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FIGURE 1. A, Buccal view of the second upper premolar before treatment. B, Occlusal view. Note the reduced mesio-distal space and soft tissue excess. C, Periapical radiograph before treatment. D, Determination of prognosis. Soft tissue and caries removal. Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

It was decided in this case to combine sectional orthodontics to distally tip the 2 molars, and to realign and create proper mesio-distal room for the second premolar in the arch for restoring the lost clinical crown of that tooth. The possibility of failure to use this tooth after movement was taken into account because the alternative of implant replacement after completion of orthodontics was more favorable and less complicated. The decay was removed (Fig 1) and the tooth was temporarily restored with glass ionomer (Fuji II, Alsip, IL). Movement onset was initiated by oral hygiene instructions and commenced with tipping the 2 molars distally against the arch to open proper space for pulling the second premolar buccally. After reaching the desired bucco-palatal position, the tooth was splinted and stabilized for 3 weeks (Fig 2). The patient was referred to a specialist in endodontics for root canal treatment of the first molar and retreatment of the second premolar. A metal cast post and core was prepared for the premolar tooth and the molar was restored with an immediate amalgam core build up.10 The situation was evaluated more than 4 months after end of the movement. Soft tissue health was satisfactory, the mesio-distal space regained was stable, the lost embrasures were restored, root canal therapy presented successful healing, and the new occlusal scheme was well accepted by the patient. This re-evaluation resulted in a decision to maintain and restore the second premolar and use it as an abutment tooth in the planned prosthetics. Accordingly, treatment was finalized with a 2 unit porcelainfused-to-metal bridge to gain stability and retention (Figs 3, 4).

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FIGURE 2. A, The second upper molar after distal tipping before the first molar pull back. The second premolar is restored with glass ionomer as a temporary restoration. B, The upper left maxillary molars are moved distally. The second premolar is ready to be repositioned in the arch. C, Movement onset of the upper second premolar to the arch. D, The second premolar in the arch is prepared to receive a provisional acrylic restoration. Note the regained space.

TEETH REALIGNMENT FOR SINGLE IMPLANT RESTORATIONS

FIGURE 4. A, Lateral view of the prepared teeth ready for impression taking. Note the healed soft tissues and the properly repositioned premolar tooth. B, Lateral view 6 months after cementation. C, Lateral view in occlusion after 18 months in the mouth. D, Vertical bite wing radiograph taken during a periodic maintenance at 9 years. Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

A 43-year-old woman presented to the clinic with a complaint of bleeding, spaced dentition, and a missing upper left premolar. The patient was diagnosed as having generalized aggressive periodontitis with spaced dentition, a result of the periodontal disease and the missing upper posterior tooth (Fig 5). The aggressive disease was treated accordingly and augmented with antibiotics for 1 week (amoxicillin and metronidazole).11-13 Three months later, the initial preparation treatment was further commenced with an open flap debridement procedure in the third

sextant because of deep residual pockets and inadequate tissue response. As the ridge of the missing tooth area was found mesio-distally insufficient for implant placement, a sectional orthodontic appliance was designed to realign the teeth, eliminate the spaces, and regain proper room for an implant. Ligature wires were preferred over elastomeric bands because of their tendency to accumulate less plaque (Fig 6).14 Movement was completed 4 months after treatment onset, and retention was gained from a multistranded wire on the front upper teeth (between the right canine and the left first premolar) and a provisional acrylic 3 unit bridge placed on the 2 distal

FIGURE 3. A, Periapical radiograph at the end of the movement before endodontic therapy. B, Periapical radiograph at 4 months for evaluation before prosthetics. C, Master model presenting the achieved proper mesio-distal position of the premolar. D, The fabricated porcelain fused to metal bridge.

FIGURE 5. A, Frontal view during the initial preparation stage. Note the anterior spaced dentition. B, Occlusal view during the initial preparation stage. C, Lateral view presenting the missing tooth area. Note the reduced mesio-distal space. D, Palatal lateral view of the maxillary reduced mesio-distal missing tooth area.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

LOSS OF A SECOND PREMOLAR IN A PERIODONTALLY INVOLVED PATIENT– CASE 2

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FIGURE 6. A, Frontal view at teeth engagement and treatment onset. B, Periapical radiograph before treatment. Note the drifting adjacent teeth and the reduced space in the missing premolar area. C, Lateral view at the end of treatment. Note the amount of space regained for the missing tooth area and the realigned arch. D, Periapical radiograph at end of treatment with space regained. A problem is observed around the mesio-buccal root of the first molar. Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

upper molars (including a mesial cantilever in the regained missing premolar area). Four weeks after the end of the orthodontic treatment an implant was placed (3.75 ⫻ 13 mm; MIS Dental Implant Systems, Shlomi, Israel). During implant healing, the mesio-buccal root of the left upper first molar was separated and extracted following an episode of acute inflammation (Fig 7). Prosthetic work included a single implant crown replacing the missing premolar and 2 porcelain fused to metal units on the upper left molars. The porcelain was designed

FIGURE 8. A, The final implant crown and the 2-unit porcelain bridge restorations. B, Lateral view with the final prosthetics. C, Lateral close-up view of the final work at 1 year. D, Palatal lateral view of the final work at 1 year. Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

to compensate for the loss of 1 of the roots of the restored upper first molar (Fig 8). A MANDIBULAR ABSENT LEFT SECOND PREMOLAR– CASE 3

A 46-year-old woman presented to the clinic with an old ill-fitting porcelain-fused-to-metal bridge made on the first and second left mandibular molars with a mesial cantilever to replace the congenital absent mandibular second premolar (Fig 9). The patient complained of discomfort and pain during mastication from that area. Examination revealed the need to extract the periodontally involved third molar and to replace the existing prosthetics. The missing second premolar area was evaluated for implant placement and a problem was encountered only in the mesio-distal dimension (Fig 10).15-17 A

FIGURE 7. A, Lateral view at the end of treatment. A provisional acrylic bridge maintains the regained space. B, Occlusal view at the end of treatment after splinting with a multistranded wire and composites. C, Occlusal view after implant loading and first molar’s mesiobuccal root separation and extraction. D, Lateral occlusal view of the treated area before impression taking.

FIGURE 9. Occlusal view of a porcelain-fused-to-metal bridge compensating for a missing lower second premolar with a mesial cantilever. Note the reduced mesio-distal space in the missing tooth area.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

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FIGURE 10. Bite wing radiograph presenting the missing tooth area and an ill-fitting prosthetic. Note the reduced mesio-distal spaces, the teeth inclination, and the root proximity. Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

regular platform implant was placed (3.75 ⫻ 13 mm; Branemark System; NobelBiocare, Yorba Linda, CA) with correct inter-implant–tooth distance in the mesial side of the implant, leaving enough room for the creation of a normal papilla. After proper healing time and integration of the implant,1 the 2 left mandibular molars were tipped back against the integrated implant with rubber separating bands (Fig 11).18 The exerted forces against the implant opened adequate space interproximally between the implant and the first molar, with formation of proper papilla and embrasure

TEETH REALIGNMENT FOR SINGLE IMPLANT RESTORATIONS

FIGURE 12. A, Occlusal view of the molars before movement onset. Note the proximity between the molar and the implant provisional crown. B, Occlusal view of the regained interproximal space distal to the implant with good soft tissue healing. C, Lateral view post movement with adapted provisional acrylic restorations. D, Elastomeric impressions of the implant head and the 2 molars (Speedex, Coltene, IL). Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

space distal to the implant. The acrylic provisional restorations were adjusted accordingly and the situation was evaluated 4 weeks after movement ended. As healing and stabilization were uneventful, it was decided to fabricate 3 individual crowns, a Procera AllCeram (NobelBiocare) on the implant and a Captek crown on each molar (Precious Chemicals, Altamonte Springs, FL) (Figs 12, 13).

FIGURE 11. A, Left bite wing radiograph 4 months after implant placement with provisional restorations. Note the cervical and root proximity compromising any prosthetic solution. B, Lateral view after implant loading presenting the proximity problem. Note the absence of the papilla distal to the implant provisional. C, Occlusal view of the rubber separating bands before movement. D, Lateral view of the rubber separating bands before movement.

FIGURE 13. A, Lateral view of the ceramic abutment (CerAdapt; NobelBiocare) emerging ideally in healthy tissues and a Captek Coping on the first molar (Precious Chemicals). B, Bite wing of the final crown restorations on the implant (Procera AllCeram; NobelBiocare) and the 2 molars (Captek; Precious Chemicals). Note the regained bone distal to the implant and interproximally between the molars. C, Occlusal view of the porcelain crown restorations. D, Lateral view of the porcelain crown restorations. Note the proper embrasures and soft tissue health.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

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Discussion Today, conventional restoration of a missing tooth using a full coverage porcelain bridge or bonded etched cast restorations (Maryland bridges) is no longer considered a first treatment of choice.19,20 Single implant restorations became common daily practice when replacing a missing permanent tooth because of congenital or various other reasons, such as caries, periodontal disease, or traumatic events. Careful examination of the missing tooth area in all aspects is imperative to verify that implant placement is feasible. The dimensions and quality of the alveolar ridge must be suitable coronally and apically; the same applies for the adjacent teeth position, which should not interfere with implant placement. Diagnosed improper space may be corrected using orthodontics to realign the teeth and their root apices adjacent to the missing tooth area to provide adequate space for implant positioning. Orthodontic movement has positive influence on the bone because it generates bone, along with the displacement, thereby remodeling and rebuilding the alveolar process in all dimensions. Studies have shown that alveolar cortical bone will be deposited apposed the slowly moving tooth, provided that the gingival tissues are healthy. The periosteum on the buccal and lingual surfaces will form bone as teeth are moved into the edentulous site. This results in topographic changes that have a significant effect on the subsequent stages of treatment.21 Therefore, the necessity for guided bone regeneration should be reevaluated after the orthodontic phase is over and teeth are repositioned as indicated. In case 1, the movement realigned the teeth in the arch along with the surrounding bone. The tooth successfully served as a mediator on the bone and then the decision whether to discard or use that tooth was made without compromising. Dental implants can be placed in adults at any time after the edentulous space has been opened and modified. It is easier to place after the appliance is removed, unless the implant is planned to act as a space maintainer (as in case 2). In such cases, the appliance is removed after the implant is loaded with a crown that is integrated in the arch. In many cases, implants are the major anchoring device for orthodontic movement. In these cases, the implant must integrate first and then be engaged to the teeth.22 Case 3 is a unique example because the minor orthodontic movements made were against a fully integrated implant. The mesial tooth wall–implant platform relations in this case were ideally set and the correct distal relations were regained with the aid of rubber separating bands.18 This technique may be incorporated in cases where a missing molar area in

FIGURE 14. A, Bite wing radiograph presenting 2 implants in a former first molar area. Note the proximity and mesial inclination of the second right molar. B, Bite wing radiograph after back tipping with rubber separating bands of the second molar. Note the interproximal area between the distal implant and the second molar. Smidt, Venezia, and Tandilch. Teeth Realignment for Single Implant Restorations. J Oral Maxillofac Surg 2007.

the mandible is in debate (Fig 14), especially where a wide implant cannot be used and the mesio-distal space is limited for 2 implants. The mesial implant should be placed in the ideal position and so is the distal implant in its mesial aspect. In the distal aspect of that implant, the absent papilla will be regained after proper healing using rubber separating bands. This is a simple and easy technique that may be used in the office with no need for referrals or special tools or skills and has minimal effect on chair time. This article discussed some aspects of arch malalignment and missing teeth problems. Although implant-assisted crowns are considered the treatment of choice by many clinicians, it is important to stress that teeth are not obsolete and a clinician should carefully evaluate the situation before sacrificing a tooth. Sometimes a tooth is considered hopeless but most valuable during the process of treatment.23 Case 1 clearly stresses this issue, as tooth movement restored the lost space, rearranged the bone and soft tissues, and made treatment simple and uncompromised. Single implant tooth replacement along with an orthodontic phase of treatment in cases 2 and 3 assisted in the achievement of optimal results and allowed for less extensive prosthetic treatment. Any orthodontic treatment requires careful planning of the stabilization phase before onset of movement to maintain treatment results. It is imperative to envision the outcome of the treatment before movement onset and to plan the measures for retention. Restored implants combined in the arch during or after this phase of treatment are the best anchoring devices for this purpose.

46 Acknowledgment The authors thank Dr Nuphar Blau-Venezia for her invaluable contribution and persistence in the process of preparing this article.

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TEETH REALIGNMENT FOR SINGLE IMPLANT RESTORATIONS 12. Pavicic MJ, van Winkelhoff AJ, Douque NH, et al: Microbiological and clinical effects of metronidazole and amoxicillin in Actinobacillus actinomycetemcomitans-associated periodontitis. A 2-year evaluation. J Clin Periodontol 21:107, 1994 13. van Winkelhoff AJ, Tijhof CJ, de Graaff J: Microbiological and clinical results of metronidazole plus amoxicillin therapy in Actinobacillus actinomycetemcomitans-associated periodontitis. J Periodontol 63:52, 1992 14. Forsberg CM, Brattstrom V, Malmberg E, et al: Ligature wires and elastomeric rings: Two methods of ligation, and their association with microbial colonization of Streptococcus mutans and lactobacilli. Eur J Orthod 13:416, 1991 15. Devlin H, Ferguson MW: Alveolar ridge resorption and mandibular atrophy. A review of the role of local and systemic factors. Br Dent J 170:101, 1991 16. Ostler MS, Kokich VG: Alveolar ridge changes in patients congenitally missing mandibular second premolars. J Prosthet Dent 71:144, 1994 17. Atwood DA: Some clinical factors related to rate of resorption of residual ridges. 1962. J Prosthet Dent 86:119, 2001 18. Smidt A, Venezia E: Gaining adequate interdental space with modified elastic separating rings: Rationale and technique. Quintessence Int 33:409, 2002 19. Creugers NH: Resin-bonded bridges. A status report for the American Journal of Dentistry. Am J Dent 4:251, 1991 20. Creugers NH, Kayser AF, Van’t Hof MA: A seven-and-a-half-year survival study of resin-bonded bridges. J Dent Res 71:1822, 1992 21. Melsen B, Agerbaek N: Orthodontics as an adjunct to rehabilitation. Periodontol 2000 4:148, 1994 22. Creekmore TD, Eklund MK: The possibility of skeletal anchorage. J Clin Orthod 17:266, 1983 23. Salama H, Salama M: The role of orthodontic extrusive remodeling in the enhancement of soft and hard tissue profiles prior to implant placement: A systematic approach to the management of extraction site defects. Int J Periodont Restor Dent 13:312, 1993