International Journal of Periodontics & Restorative Dentistry, 02/2000

In 1993 the Department of Implant Dentistry at New York University College of Dentistry began a long-term clinical, histologic, histomorphometric, and radiographic study of the sinus elevation procedure. One of the parameters under evaluation in this study is the effect of barrier membrane placement on the creation of vital bone in the grafted sinus cavity. This report presents a histologic and histomorphometric evaluation of healing with and without the placement of an expanded polytetrafluoroethylene (e-PTFE) barrier membrane over the lateral window at the time of sinus grafting. The data were collected from 12 patients who underwent bilateral sinus elevation surgery. In each of these 12 patients the same grafting material was used in both sinuses, making the presence or absence of an e-PTFE barrier membrane the only controlled variable. Under the conditions of this study, the results indicate that (1) placement of the barrier membrane tends to increase vital bone formation; (2) placement of a barrier membrane has a positive effect on implant survival; and (3) membrane placement should be considered for all sinus elevation procedures.

This case report study examined the effect of adjunctive use of Emdogain in the treatment of intrabony periodontal defects. Seventy-two consecutively treated defects in sixty-one patients were included. Efficacy of treatment was evaluated at 12 months by assessment of probing depth reduction, probing attachment level gain, and radiographic bone gain from standardized radiographs. Initial pocket depth averaged 8.3 mm, and the mean probing attachment level was 10.0 mm. The mean radiographic defect depth was 5.3 mm. At 12 months, mean pocket depth reduction was 4.7 mm and mean probing attachment level gain was 4.2 mm. Radiographic bone level gain averaged 3.1 mm and defect fill averaged 70%. The only variables significantly affecting radiographic bone gain were bleeding on probing and smoking. It was concluded that Emdogain treatment of one- and two-walled intrabony defects in a periodontal practice will result in a clinically significant gain of probing attachment level and radiographic bone that is similar to that reported in controlled clinical trials.

The concept of overbuilding the implant site in the esthetic zone is paramount in creating the inconspicuous implant restoration. If teeth are congenitally missing, the site may be underdeveloped. Tooth extraction and trauma may lead to ridge deformities. The goal is to create an enhanced site for the restorative clinician. This site can then be molded to an ideal gingival framework. Cases are used to illustrate surgical and orthodontic techniques for preserving and overbuilding the implant site in the esthetic zone.

The Procera AllCeram system is indicated for manufacturing all-ceramic crowns for single-tooth restorations in the anterior and posterior regions. In addition, it is possible to create metal-free superstructures on CeraOne abutments from the Brånemark implant system or crowns on individually prepared aluminum oxide abutments (CerAdapt). The Procera copings, which are manufactured using computer-aided design/manufacturing technology, are characterized by very good mechanical properties. Ceramic veneers tailored to the copings offer excellent esthetics, favorable abrasion behavior, and an ideal surface structure for noninflammatory apposition of the periodontal or periimplant tissues. The present article offers an overview of previous scientific studies, describes clinical and laboratory procedures, and presents case reports.

There has been increased discussion on the advantages of a one- versus a two-stage surgical approach in the placement of dental endosseous implants. This study evaluated the influence of early implant exposure on crestal bone height adjacent to the implant surface and Periotest values at uncovering in the baboon. Forty-eight implants (24 commercially pure titanium, 24 titanium alloy) were placed in maxillary and mandibular posterior sites in 6 baboons. Implant exposure was evaluated weekly for 3 weeks after implant placement. The level of bone adjacent to the dental implants was measured at placement from the top of the implant collar to the crest of the bone at the mesial, distal, buccal, and lingual surfaces. The maxillary sites were measured again at a 6-month uncovering, while the mandibular sites were measured at a 3-month uncovering. Periotest readings were also recorded at uncovering. Early implant exposure was more common in the mandible, with the majority occurring by the second week postplacement. There were no significant differences in the crestal bone height changes at uncovering between the pure titanium and alloy implants in either arch. In the maxilla, the changes in crestal bone height were not statistically different between exposed and nonexposed implants at any aspect. In the mandible, the difference in 3-month changes between exposed and nonexposed implants was significant for the distal, buccal, and lingual aspects. The overall percentage of implants with a Periotest reading in the 'good' category was greater for the nonexposed sites as compared to exposed sites. The results of this study suggest that the two-stage surgical approach results in a better clinical outcome as compared to the one-stage approach in the baboon model.

The aim of this prospective clinical 2-year study was to determine whether the placement of the proximal margins of crowns within the zone of the biologic width results in periodontal alterations. In 41 patients, 116 prepared teeth as well as 82 unrestored, healthy contralateral teeth were examined. The following indices were determined before as well as 3, 6, 12, and 24 months after preparation: hygiene index, papillary bleeding index (PBI), and probing depth. After preparation, the distance between the restoration margins and the alveolar crest was measured with a modified periodontal probe on both proximal aspects of each tooth. These values were classified into 3 groups: I = = 1 mm between crown margin and alveolar crest, II = 1 to 2 mm, and III = > 2 mm. In addition, radiographs were taken directly after cementation of each restoration and after 12 and 24 months. The hygiene index did not significantly vary during the investigation, but PBI increased in all groups. The highest PBI increase was found in group I; in this group, the most significant increase was found between 3 and 6 months after preparation. The mean probing depth only increased in group I during the first 3 months after preparation on the mesial aspects. Only minor changes were found on the distal aspects of the teeth in group I and on all aspects in groups II and III. No alterations of the bone levels were diagnosed on the radiographs. These results indicate that the location of the restoration margins within the zone of the biologic width may impair the periodontal health of restored teeth.

Implant angulation is of utmost importance for fabrication of esthetic, hygienic, and functional prostheses, even in the treatment of completely edentulous patients. Most mandibular surgical templates are not reliable because of a lack of stability resulting either from severe resorption of the mandible or from the interference of mucoperiosteal flaps elevated during surgery. This article describes a technique for fabrication and surgical application of a stable template for the completely edentulous mandible. By combining the mandibular template with a maxillary duplicate denture, the problem of lack of stability can be overcome. A consistently reliable reference for implant placement in the edentulous mandible, specifically in relation to implant angulation (trajectory), can be obtained.

Guided bone regeneration via an osteopromotive barrier is indicated in different alveolar bone deficiencies and in periimplant bone destruction around pathologically denuded exposed implants. Regeneration of the osseous volume is determined by understanding the biologic behavior response of hard and soft tissues in guided tissue regeneration procedures. Consequently, a meticulous surgical approach is mandatory to preserve wound healing cascades and tissue stability. However, hard tissue augmentation in the nonsupported coronal direction has been unpredictable. A case report is presented in which a severely defected ridge around a pathologically exposed functional implant combined with a destructive extraction site was restored and regenerated. Bovine bone mineral particles (Bio-Oss) served as the graft material and were followed by an expanded polytetrafluoroethylene (e-PTFE) occlusive membrane as a bilateral regenerative tissue guide. Subsequently, 2 additional implants were placed in the augmented hard tissue ridge.

Immediate placement of implants into fresh extraction sockets has the advantages of decreasing the recommended period of healing, reducing the resorption of the alveolar bone, and achieving optimal esthetic results. A high rate of success with immediately placed implants has been reported in the literature. Conventional intervention involves 2 or 3 surgical visits, and this may not be accepted by the patient or may be of some inconvenience. The technique described involves only one surgical visit at which a transmucosal endosseous root-form implant is inserted, followed by application of a resorbable membrane.