International Journal of Periodontics & Restorative Dentistry, 04/2003

Preservation of alveolar bone volume following tooth extraction facilitates subsequent placement of dental implants and leads to an improved esthetic and functional prosthodontic result. The aim of the present study was to assess bone formation in the alveolus and the contour changes of the alveolar process following tooth extraction. The tissue changes after removal of a premolar or molar in 46 patients were evaluated in a 12-month period by means of measurements on study casts, linear radiographic analyses, and subtraction radiography. The results demonstrated that major changes of an extraction site occurred during 1 year after tooth extraction.

Part 1 of this article discussed the rationale for a thorough occlusal evaluation of all patients requiring dental care. Those patients in need of complex reconstruction frequently require modification of one or more of six inter-related elements that comprise an occlusal scheme. Two of these elements, the centric relation position of the mandible and the vertical dimension of occlusion, were discussed. This article will continue the discussion of the remaining elements, beginning with the posterior plane of occlusion. The position and function of the maxillary incisal edges, as well as those of the mandibular incisal edges, will then be reviewed, followed by a consideration of posterior dental occlusal anatomy. These six elements dictate the function and esthetic nature of the final prosthesis, and their successful integration enhances the long-term prognosis of the reconstruction.

A new technique using calcium sulfate augmentation for root coverage is described. Three consecutive cases were treated with the calcium sulfate technique adjacent to teeth being treated with the classic connective tissue grafting technique. Although this is only a pilot study, the postoperative results of the calcium sulfate-treated sites showed similar tissue shape, color, and contour to the adjacent grafted sites. The amount of root coverage was also similar.

Treatment of intrabony periodontal defects with an enamel matrix derivative (EMD) has been shown to predictably enhance periodontal regeneration. The aim of the present study was to evaluate the 4-year results following treatment of intrabony defects with EMD. Thirty-three patients with a total of 46 intrabony defects were treated. Each patient exhibited at least one intrabony defect with a probing depth >= 6 mm as identified by probing and on radiographs. The following clinical parameters were evaluated prior to and 1 and 4 years after treatment: probing depth, recession of the gingival margin, and clinical attachment level. The primary oucome variable was clinical attachment. Mean probing depth was reduced from 8.1 ± 1.8 mm to 3.8 ± 1.2 mm at 1 year and to 4.0 ± 1.2 mm at 4 years. No statistically significant differences were found between the mean probing depth 1 and 4 years postoperative. At 1 year, the mean recession increased from 1.9 ± 1.5 mm to 3.2 ± 1.8 mm; at 4 years, it was 2.8 ± 1.2 mm, a statistically significant improvement compared to the 1-year results, but still significantly increased compared to the baseline. The mean attachment level changed from 10.0 ± 2.4 mm to 7.0 ± 2.1 mm at 1 year and 6.8 ± 1.9 mm at 4 years (no statistically significant difference). The clinical improvements obtained following treatment with EMD can be maintained over a 4-year period.

Common complaints associated with the Kennedy Class I (bilateral free end) and Class II (unilateral free end) removable partial denture situations are lack of stability, minimal retention, and unesthetic retentive clasping. Some of the same complaints have been reported for implant overdentures with only anterior implants. Starting in 1995, 10 of these patients were treated at the University of Washington with posterior osseointegrated implants to provide stability and/or retention of the removable prostheses, eliminating the need for clasps when possible. This article describes implant alternatives and prosthesis designs and presents a follow-up clinical evaluation of at least 1 year consisting of patient satisfaction, radiographic examination, and soft tissue health. Two groups were evaluated. Group 1 included patients whose implants were used as vertical stops for mandibular distal extension prostheses. Care was taken to ensure that the implants were not loaded laterally by creating a single-point contact at the center of a modified healing abutment. In these cases, sufficient retention was available from the anterior teeth and/or implant abutments. Group 2 included patients whose implants required retention because of lack of adequate tooth abutments. In those cases, a resilient type of attachment was used, which allowed for a small divergence from the path of insertion. Results indicated consistent increased satisfaction in all patients, minimal component wear, no radiographic evidence of excessive bone loss, and stable peri-implant soft tissues.

Ninety sites were treated with either sinus augmentation therapy using only Bio- Oss (31 sites), or extraction socket and ridge augmentation therapy using only Bio- Oss beneath secured resorbable or titanium-reinforced nonresorbable membranes (59 sites). Core biopsies were taken at intervals ranging from 4 to 13 months. The 12 core biopsies taken 12 to 13 months postoperative (five sinus augmentation sites and seven extraction socket/ridge augmentation sites) demonstrated distinct Bio-Oss particles in an average of only 0.13% of the core biopsy volume. Bone regeneration was evident in all specimens.

This study looked at a bone-substitute biomaterial (Biostite) used to fill bone defects around immediate implants in humans. Ninety-six peri-implant bone defects were treated without the use of membranes, comparing two groups: group A = filling the defect with Biostite, and group B = no defect fill. After 4 to 6 months of healing, group A revealed higher percentages of implants covered by new, bone-like tissue (67% in group A, 34% in group B). Endochondral osteogenesis was demonstrated histologically in the regenerated tissues in alveolar sites treated, allowing the hypothesis of bone induction from the filling material used.

A synthetic, nonceramic resorbable hydroxyapatite (R-HA) was applied to augment the subantral area in 10 consecutive sinus lift procedures in humans. Implants were simultaneously placed in eight patients; in the remaining two, where residual bone height was less than 3 mm, a two-stage surgical approach was carried out. The aim of the study was to examine, clinically and histopathologically at 12 months, the healing pattern of these augmented sinuses around the implants. In the simultaneous technique, radiopaque grafted mineral surrounded the implants. In the twostage technique, R-HA particles filled the augmented site and were confined to the subantral area. At the uncovering phase, all implants (n = 36) were stable, with no clinical bone resorption around the cervix. A 2.5-mm trephine bur was used to collect specimens from the 10 augmented sites at the lateral-deep area. Histologically, new bone formation was evident in all examined cores. R-HA particles were primarily surrounded by newly formed bone, mostly woven bone, in different stages of remodeling. However, in the deep areas of the specimen cores, lamellar bone fragments were also seen. Morphometric measurements showed that the mean bone area of the 10 sites was 28.1% at the lateral/external side and 37.8% at the deep/inward side. Under polarizing microscopy, the mean lamellar:woven bone ratio was 1:7.2 at the lateral side and 1:4.2 at the deep end. Differences were statistically significant. R-HA proved to be a suitable filler material for osseointegrated implants in sinus augmentation procedures, since it showed both biocompatible and osteoconductive properties.

This article reports on a case of root resorption following a clinically successful root coverage procedure with a subepithelial connective tissue graft on a maxillary lateral incisor. Two years after the graft procedure was performed, the tooth was extracted in conjunction with the buccal attachment apparatus. Histologic examination of the specimen revealed signs of active resorption of the dentinal surface and bone formation in the deepest portion of the resorption cavity. Possible causative factors of the root resorption process are discussed.