International Journal of Periodontics & Restorative Dentistry, 06/2006

Dental rehabilitation of partially or totally edentulous patients with dental implants has become common practice in the last few decades, with reliable long-term results. However, local conditions of edentulous alveolar ridges may be unfavorable for implant placement. Vertically deficient alveolar ridges, in particular, may have insufficient bone volume to hold implants of adequate dimensions, making implant placement difficult or impossible. To correct this situation, a variety of surgical procedures have been proposed, including onlay bone grafts, vertical guided bone regeneration, and alveolar distraction osteogenesis. Distraction osteogenesis is a biologic process of new bone formation between the surfaces of bone segments that are gradually separated by incremental traction. This process is initiated when a traction force is applied to the bone segments and continues as long as the callus tissues are stretched. This traction force, in turn, generates tension within the tissues that connect the bone segments, which stimulates new bone formation parallel to the vector of distraction. The aim of this article is to provide clinicians with the historical background of and biologic basis for the concept of distraction osteogenesis, which can be traced back to the 1800s. Finally, a clinical case is presented to demonstrate a step-by-step application of alveolar distraction osteogenesis as a treatment protocol in a partially edentulous ridge for improvement of esthetics.

The present blinded, randomized, controlled investigation histomorphometrically evaluated the vital bone formed following bilateral grafting with two different materials-Puros, a mineralized cancellous bone allograft (MCBA), and Bio-Oss, an anorganic bovine bone matrix (ABBM)-at 26 to 32 weeks following graft placement. Thirteen patients were selected who required bilateral sinus augmentation. Following elevation of the lateral sinus walls, one material was placed in the right sinus and the other in the left sinus, as determined by randomized choice. Twenty-six to 32 weeks after grafting (the same time frame was used for each individual patient), a trephine core was taken from the previously elevated lateral wall area and sent for histomorphometric analysis. Cores were obtained from 22 healed sinus augmentations in 11 patients. Eight patients provided bilateral cores, two patients had intact MCBA cores but inadequate ABBM cores, and another patient had an intact ABBM core but an inadequate MCBA core. Histomorphometric analysis of 10 MCBA cores and 9 ABBM cores revealed average vital bone content of 28.25% and 12.44%, respectively. The average percentage of residual nonvital bone was 7.65% in the MCBA cores and 33.0% in the ABBM cores. Significantly more bone was formed in the MCBA sites (n = 8 patients, paired t test). Histologically, both MCBA and ABBM particles were surrounded by new bone, osteoid, and osteoblasts. A higher average percentage of new vital bone was seen around the MCBA particles than around the ABBM particles.

The aim of the present study was to evaluate whether it is possible to orthodontically move migrated teeth into infrabony defects augmented with a biomaterial. Three adult patients suffering from chronic periodontitis were treated. Each of the patients presented with an infrabony defect adjacent to a migrated maxillary central incisor. After cause-related therapy was completed, a surgical procedure was performed using the papilla preservation technique. The defects were filled with a collagen bovine bone mineral; after 2 weeks, an orthodontic device was activated using light, continuous forces. Orthodontic treatment time varied from 4 to 9 months; during this period, patients were enrolled in an oral hygiene recall program. At baseline and 6 months after the end of therapy, probing pocket depths (PPD) and clinical attachment levels (CAL) were assessed. In addition, the vertical and horizontal dimensions of the defects were measured on standardized radiographs. Residual mean PPD was 3.33 mm, with a mean reduction of 3.67 mm. Mean CAL gain was 4.67 mm. Radiologic vertical and horizontal bone fills were, on average, 3.17 mm and 2.0 mm, respectively. The present case series shows the effectiveness of a combined periodontic-orthodontic approach for the treatment of infrabony defects. Reduction of PPD to physiologic values, CAL gain, and radiologic defect resolution were obtained. No detrimental effects from the orthodontic movement were observed on the augmentation material.

The objective of this study was to evaluate the potential of an allogeneic bone matrix (Grafton, Osteotech) to regenerate now bone, new cementum, and a new periodontal ligament around teeth previously contaminated by bacterial plaque. Four patients with chronic advanced periodontitis and who were scheduled for full-mouth extraction were enrolled in the study. One patient dropped out from the study before any therapy began. One tooth with an intraosseous defect in each patient was selected for treatment. Measurements of probing depth, gingival recession, and clinical attachment level were made. After flap reflection, a root notch was placed at the apical level of calculus, the root was debrided, and allogenic bone matrix was inserted into the defect. After 6 months of healing, the teeth were removed en bloc and evaluated histologically for a new attachment apparatus. Two of the three teeth demonstrated regeneration of new bone, cementum, and periodontal ligament.

Retreatment of a failed prosthetic rehabilitation often presents a challenge for both clinicians and patients. Endosseous dental implants are a commonly used treatment modality to restore esthetics and function. Implant protocols differ considerably with regard to healing time and the number of surgical procedures required. This has a great impact on the treatment strategy used and therefore significantly influences patient acceptance. The present case report describes the rehabilitation of a failed maxillary anterior fixed partial denture using immediate implant placement and provisionalization. This tissue-related, esthetically driven treatment strategy is comprehensively presented with a follow-up of 12 months postoperatively.

A novel approach to augmenting alveolar ridges simultaneously with implant placement is presented. The technique is based on the use of custom-shaped osteosynthesis plates, which are fixed to the bone with miniscrews. The plates provide a rigid scaffolding for bone chips. Resorbable barriers are used to cover the plates and the grafts. The results of three selected cases are presented. This technique is relatively simple, can be used in almost any clinical situation, and can provide excellent results.

This case series presents the use of acellular dermal matrix (ADM) as a barrier membrane in reconstructing non-spacemaking buccal dehiscences associated with simultaneous implant placement in locally deficient ridges. Five sites in four healthy nonsmoking patients were treated with a combination of the mucogingival pouch flap technique, sandwiched layering of mineralized human cancellous and cortical bone grafts, and ADM as a barrier membrane. Three sites encountered 2 to 4 mm of membrane exposure after 2 weeks of healing time. However, all sites were completely covered at 3 months. None of the cases exhibited implant exposure throughout the entire healing period. At the 6-month re-entry surgery, ADMassisted guided bone regeneration achieved a mean of 86.5% height gain and critical bone thickness of 1.8 mm or greater, with clinical bone density equivalent to that of the native bone.

The purpose of this study was to investigate the precise effect and rank the importance of cavity preparation and restoration variables on human pulp vitality. Fiftythree Class V unexposed cavities were prepared and restored with calcium hydroxide/amalgam, resin-modified glass ionomer, zinc oxide-eugenol, resin composite, or zinc polycarboxylate materials. Pulp vitality was reduced by the remaining dentin thickness of the cavity preparations, whereas the other variables, including the type of restorative material, had little effect. Restorative materials cause minimal pulp damage in isolation; it is more important to minimize the removal of intact dentin to maintain the vitality of teeth.

The current study used advanced three-dimensional (3-D) images with quantitative information to show the bottom of an intrabony defect. The 3-D data were corrected by means of a compact computerized tomography unit for dental use using a cone-beam method (3DX, Morita). 3-D images at the bottom of the intrabony defect in which the distance between the surface of the tooth and bone reached 0.5 mm were combined to provide a reconstructed image of the entire defect. Advanced 3-D images with quantitative information to show the bottom of an intrabony defect can display visually and in three dimensions the depth of an intrabony defect all around a tooth. Moreover, the distance between the cementoenamel junction and the bottom of an intrabony defect can be measured automatically using this technique.