Implants can readily be placed and restored in congenitally missing maxillary lateral incisor sites with predictable results if surgical, periodontal, and prosthodontic conditions are favorable. A case report using dental implants to replace bilateral congenitally absent maxillary lateral incisors for teenage female identical twins is presented.
Research advances throughout the years have enabled dentists, in concert with skilled laboratory technicians, to fabricate esthetically pleasing and functional restorations. Congenitally missing maxillary lateral incisors pose a difficult esthetic and treatment-planning problem for clinicians. Age, location, space limitations, alveolar ridge deficiencies, uneven gingival margins, occlusion, and periodontal factors often necessitate an interdisciplinary approach.
The incidence of congenitally missing maxillary lateral incisors has been reported to range from between 1% and 2%1 to as high as 5%.2 Maxillary lateral incisors are the most common congenitally missing teeth after upper and lower second premolars. Sex differences have been found to be negligible, with slightly more females affected as compared with males.1 Treatment options include orthodontic movement of cuspids into lateral incisor sites, prosthodontic restorations including fixed and removable prostheses and resin-bonded retainers, and single tooth implants.3
Implants do not require preparation of natural teeth and thus can be considered the most conservative approach. Orthodontic space opening may be necessary but on occasion can compromise esthetics, periodontal health, and function.1
Parents and professionals must often decide at a child's early age on how to cope with congenitally missing maxillary lateral incisors. Orthodontic treatment to create space for implants should not be initiated before the age of 13. This will avoid the potential for alveolar bone atrophy and the risk of relapse and subsequent retreatment.4
Premature placement of implants can result in gingival disharmony and teeth positioned at different incisal levels if the adjacent teeth have not completed erupting.5
Two 17-year-old identical female twins presented for treatment at Temple University School of Dentistry in October 2005. Both had been under orthodontic treatment by a private practitioner since the age of 12 to create sufficient space for eventual placement of implants in bilateral congenitally missing maxillary lateral incisor sites. Both twins were wearing Hawley removable retainers with labial wires, acrylic bite plates resting against their palates, and resin prosthetic teeth in the missing lateral incisor positions (Figure 1a and b). The retainers were for esthetics and served to maintain the space until the implants could be placed and restored.
Clinical and radiographic examination (Figure 2a and b) revealed that the orthodontic treatment was successful and that sufficient space was available for implants and crowns (Figure 3a and b). Implants (3.5 × 10 mm; SteriOss Replace Select tapered, Nobel Biocare, Yorba Linda, Calif) and healing abutments were placed in the lateral incisor sites in December 2005 (Figure 4a and b). One of the twins needed slight augmentation of the buccal plate of the left lateral incisor. An osteoconductive bone substitute consisting of the mineral portion of bovine bone was used (Bio-Oss, Luitpold Pharmaceuticals, Shirley, NY). Healing was uneventful.
Healing abutments were removed and custom abutments placed in May 2006. Provisional restorations were temporarily cemented on the abutments. The twins returned 3 weeks later for the cementation of porcelain-fused-to-metal crowns. The twins and their mother were extremely pleased with the esthetic results (Figure 5a and b, Figure 6a and b).
The best treatment for replacement of congenitally missing maxillary lateral incisors is the most conservative approach that meets esthetic and functional demands. Implants do not require preparation of natural teeth, promote alveolar ridge preservation, and can facilitate achieving optimum restorative results.
Implant treatment planning in the case of congenitally missing maxillary lateral incisors depends on occlusion, anterior relationships, space requirements, and the condition of the adjacent teeth.6 Possible problems include space limitations for implant placement and prosthodontic restoration, close proximity of the apices of adjacent teeth to the proposed implant site, inadequate ridge thickness that requires augmentation, and inadequate bone support for the gingival papillae.
Close proximity of the apices of adjacent teeth may necessitate orthodontic treatment for angulation correction. Ideally, the adjacent roots should be parallel or slightly divergent. A minimum of 1 mm between the implant and the adjacent roots is recommended.
Sufficient space must exist between the central incisor and cuspid crowns to place and restore implants. Ideally, the maxillary lateral incisor crown should be approximately two thirds the crown width of the central incisor.7 If necessary, the widths of the adjacent teeth can be carefully reduced to create additional space. The reduced proximal surfaces must be highly repolished after reduction is completed. Overreduction must be avoided.
If implants are inserted and restored at too early an age, the adjacent teeth can erupt and create disharmony between the gingival margins of the implant and the natural teeth. Kokich7 recommends waiting until an adolescent male has completed growth in height. For a female, facial growth is often completed by 15 to 16 years of age. Implants can be placed earlier in females as compared with males without the risk of adjacent teeth eruption.
Sheldon Winkler, DDS, is an adjunct professor of dentistry at Midwestern University College of Dental Medicine, Glendale, Ariz. He formerly served as professor and chairman of the Department of Prosthodontics and director of advanced education, continuing education, and research at Temple University School of Dentistry. Address correspondence to Dr Winkler at Midwestern University College of Dental Medicine, 19555 North 59th Avenue, Glendale, AZ 85308. (e-mail: email@example.com)
Kenneth G. Boberick, DND, is an associate professor of restorative dentistry, Stanton Braid, DDS, is an assistant clinical professor of oral and maxillofacial pathology, medicine and surgery, Robert Wood, DDS, is an assistant professor of restorative dentistry, and Michael J. Cari, DMD, is enrolled in the advanced orthodontic program at Temple University School of Dentistry, Philadelphia, Pa.