International Journal of Periodontics & Restorative Dentistry, 04/2006

The risk of developing osteochemonecrosis is increased in patients who are taking bisphosphonate drugs and must undergo extractions or other dental surgery. Because of the difficulty in predicting and preventing osteochemonecrosis and in managing patients after it has occurred, avoidance of surgery has been advised. This paper reports on the development of this complication in a patient who received nonsurgical periodontal treatment. Although it is believed that the risk of developing this severely debilitating complication is low when treating patients nonsurgically, practitioners must be able to recognize and understand the presentation and difficulties in managing osteochemonecrosis, even when only nonsurgical therapy is performed.

This article reports on a multicenter evaluation of a novel, sterile, antigen-inactivated, mineralized block allograft in humans during a 3-year developmental period. Consecutive partially edentulous patients (n = 73) with severe localized ridge defects (n = 82) were treated with the material. After 4 to 6 months of healing, tapered screw implants were placed in the grafted bone and subsequently restored. Patients were monitored 25 to 36 months after prosthetic restoration. A biopsy was taken of one patient and submitted for histomorphometric analysis. Block allograft survival was 93% at 12 months, and resorption ranged from none (69%) to slight (0 to 2 mm) (31%) for all surviving allografts. Seven block allografts failed and were removed because of improper contouring, prosthesis impingement, and/or infection. The sites were successfully re-treated and restored with dental implants. Soft tissue dehiscence was successfully treated in seven other sites. Implant survival was 99%. One implant failed without allograft failure. It was replaced with a larger-diameter implant, treated with guided bone regeneration, and subsequently restored. Histomorphometric analysis showed rapid incorporation of the allograft at 6 months without inflammation or necrosis. The block allografts were more technique-sensitive than autografts, which necessitated meticulous surgical technique and follow-up. Short-term results for the block allografts indicated a high degree of predictability, but long-term follow-up is needed.

Large-span fixed restorations in the treatment of periodontally compromised patients are technically difficult to realize. Despite existing techniques of regenerative periodontal surgery and implant therapy aimed at preventing large spans by increasing the number of abutments, prosthetic complications do occur. The present article describes a method that introduces galvanic caps to conventional prosthetic technology, which facilitates clinical procedures and reduces complications by improving precision of fit.

This article reports the preliminary results from a clinical study involving the use of implants with a natural taper design in edentulous and partially edentulous patients. Implants were followed for at least 12 months after occlusal loading. Three hundred nine implants were placed by two periodontists (176 maxillary, 133 mandibular; 198 anterior, 111 posterior). Digital radiographs were taken immediately after implant placement and 1 year after occlusal loading. Computerized measurements were made, with distances calculated between the implant restorative platforms and the greatest heights of interproximal bone on both interproximal surfaces at the time of implant placement and 12 months postplacement. At the 12-month recall appointments, it was noted that 8 of the 309 implants had failed. Osseotite NT implants can be used in the treatment of edentulous and partially edentulous patients using two-stage, single-stage, and immediate occlusal loading protocols with survival rates equivalent to those seen for cylindrically shaped implants.

The purpose of this paper is to expand on part 1 of this series (published in the previous issue) regarding the emerging future of computer-guided implant dentistry. This article will introduce the concept of rapid-prototype medical modeling as well as describe the utilization and fabrication of computer-generated surgical drilling guides used during implant surgery. The placement of dental implants has traditionally been an intuitive process, whereby the surgeon relies on mental navigation to achieve optimal implant positioning. Through rapid-prototype medical modeling and the ste-reolithographic process, surgical drilling guides (eg, SurgiGuide) can be created. These guides are generated from a surgical implant plan created with a computer software system that incorporates all relevant prosthetic information from which the surgical plan is developed. The utilization of computer-generated planning and stereolithographically generated surgical drilling guides embraces the concept of collaborative accountability and supersedes traditional mental navigation on all levels of implant therapy.

The aim of this case report was to evaluate the ability of Bio-Oss used together with an expanded polytetrafluoroethylene, titanium-reinforced membrane to restore a vertical bone defect. Bio-Oss served as a filler material. After the membrane was removed, screw-type implants were placed. During this phase, cylindric bone samples were retrieved from the augmented area for histologic examination. The biopsy samples were composed of low-density trabecular bone with numerous interspersed graft particles. Clinical and histologic results demonstrated that this surgical technique could be a successful and predictable procedure for rebuilding a resorbed ridge to place implants.

Tissue engineering represents one of the most exciting advances in regenerative medicine. However, little has been reported on the application of tissue engineering for regeneration of periodontal tissues. Therefore, the aim of this study was to show how a technique based on tissue engineering principles can be applied to periodontology. Mesenchymal stem cells (MSCs) were isolated from a patient's iliac crest marrow aspirates. Platelet-rich plasma (PRP) was isolated from peripheral blood. Full-thickness periodontal flaps were elevated and the root surfaces were scaled and planed. A MSCs- PRP gel was prepared and applied to the root surface and adjacent defect space. The primary outcome measures were changes in pocket depth, clinical attachment level, bleeding on probing, and defect bone fill. Re-examination demonstrated that the treatment, including the application of MSCs-PRP gel at periodontal sites with angular defects, resulted in a 4-mm reduction in probing depths and a 4-mm clinical attachment gain, while bleeding and tooth mobility disappeared. Radiographic assessments showed that the bone defect had been reduced in depth. Interdental papillae supported by this tissue engineering technology regenerated. The use of MSCs in PRP gel might be helpful for periodontal tissue regeneration, treatment of esthetically sensitive sites, and reduction of patient morbidity.

The timing of implant placement and loading following tooth extraction has recently undergone substantial reconsideration. The authors tested a protocol of immediate loading of single implants placed at the time of tooth extraction in a consecutive case series. Thirty-three patients received a single implant-supported crown to replace a maxillary anterior tooth at the time of extraction. Regular recalls were planned for the following 4 years. One implant did not integrate, and another became unstable secondary to facial trauma. Overall patient satisfaction and clinical and radiographic parameters were good.

The purpose of this study was to compare misfit-induced strains on implant-supported superstructures fabricated by two impression techniques and two different elastomeric impression materials. A master cast hosting four Straumann implants was constructed. On this cast, a total of 21 implant-level impressions were made by the direct technique using a polyether impression material and synOcta screwed aluminum impression caps (PE-D), and by the indirect technique using polyether (PE-IN) or polyvinylsiloxane impression material (VPS-IN) with snap-on impression caps and synOcta plastic positioning cylinders. Two casts were randomly selected from each group of seven, and a total of four screw-retained superstructures, supported by either two or four implants (one of each type on both casts), were cast in a gold alloy for each group. Linear strain gauges were bonded on the superstructures, and misfit-induced strains were recorded during superstructure connection on each of the working casts and on the master cast using a data acquisition system and corresponding software at a sample rate of 10 kHz. Connection on the implants in the master cast increased strains considerably on most of the superstructures, in comparison with strain gradients measured when the superstructures were connected on the casts from which they were fabricated (P .05). The differences in strain amplitude between connection on the cast from which the superstructure was fabricated and on the master cast were higher for superstructures fabricated by PE-D than for those fabricated by PE-IN and VPS-IN. The snap-on indirect impression technique for Straumann implants leads to acceptable superstructures, regardless of the impression material used.

The frequency and distribution of 183 consecutive cases of biopsied gingival lesions from northern Jordanians are presented here. Lesions were analyzed for age and sex of subject and location and type of lesion. Neoplasms accounted for 9% of biopsies (7% benign, 3% malignant). The most frequent neoplasm was peripheral ossifying fibroma. The maximum number of benign neoplasms occurred in patients aged 20 to 39 years, and malignant neoplasms did not occur in patients younger than 30 years. Nonneoplastic lesions accounted for 91% of cases; they comprised nine types, with pyogenic granuloma being the most frequent. The frequency and distribution of gingival lesions in north Jordan are similar to those found in other countries. Additional nationwide multicenter studies are needed to describe all aspects of epidemiology of gingival lesions in Jordan.