International Journal of Periodontics & Restorative Dentistry, 01/1996

This study assessed the efficacy, safety, and technical feasibility of inducing bone formation in an animal model of maxillary sinus floor augmentation using recombinant human bone morphogenetic protein-2 (rhBMP-2) impregnated on an absorbable collagen sponge (ACS). Bilateral antral maxillary sinus floor elevation procedures were surgically performed in six adult female Alpine-Saanen goats. Bone formation in response to the implant was evaluated using sequential radiographs, computerized tomography, and gross pathologic and histologic analysis performed at necropsy. Computerized tomographic scans documented nonosseous radiopacity in both sinuses postimplantation. Sinuses implanted with rhBMP-2/ACS subsequently demonstrated increasing radiopacity local to the implant site, while radiopacity of the negative control sinuses remained unchanged or decreased. The results demonstrated the ability of an rhBMP-2/ACS implant to induce substantive new bone formation within the maxillary sinus of goats without adverse sequelae. The rhBMP-2/ACS composite implant may represent an acceptable alternative to traditional bone grafts and bone substitutes for maxillary sinus floor augmentation procedures in humans.

Fixed restorations for patients with implant-supported abutments frequently produce an unsatisfactory mechanical, biologic, or esthetic compromise. Pure titanium transmucosal abutments have biologic advantages, and factory-milled abutments for the comparable implant interface have mechanical advantages. The ultimate restorative objective is to satisfy the patient's desire for an esthetic restoration. This can generally be accomplished with precisely positioned implants; however, compromised locations need to be corrected with modified abutments. The use of customized copings fabricated by casting to pure titanium abutments can satisfy all three criteria, and may in some situations be the restorative procedure of choice. The clinical and laboratory procedures involved in achieving these criteria are described in detail.

Recent advances in digital imaging technology have opened up new horizons for dental researchers. This study demonstrates the efficacy of a new technique for measuring regeneration in surgically created molar furcal defects. The investigators evaluated histologic material from a recently completed animal study using five adult baboons. In the animal study, surgically created molar furcation defects were treated using the principles of guided tissue regeneration. From the histologic data of one animal, a computer calculated the volume of new bone, connective tissue, epithelium, and cementum as a percentage of the original defect size. The results of this study indicated that digital imaging technology is a useful research tool for determing the volume of defect fill in surgically treated Grade II molar furcation defects in the baboon animal model.

The inferior alveolar nerve has an anterior ramification with two terminal branches, the mental nerve and the anterior plexus (or incisor nerve ). The mental nerve is described to have a superior, lateral, and posterior course formed as a loop. The length of the loop is reported to be between 3 and 7 mm. In the present study, dissection of the ramification of the inferior alveolar neurovascular bundle was performed unilaterally in 58 patients. In 43 patients no loop was found, in 13 cases the loop was 0.5 mm, and in two cases the loop was 1.0 mm long. In addition, the anatomy of the ramification with the mental and incisor canals frequently diverged in other respects from prevalent descriptions in the literature.

A histologic assay of the grafting material associated with the sinus elevation procedure would provide insight into the quality and quantity of vital bone at the implant-bone interface. This case report documented for the first time the sequential healing process of a sinus graft in the same patient at 4, 8, 12, and 20 months. Histology of trephine-obtained core samples showed that in a sinus grafted with a mixture of xenograft (80%) and autograft (20%), 12 to 20 months was required for remodeling to vital bone. The study also demonstrated that a significant amount of vital, mature bone was generated by this procedure. Quantification of the resulting bone and comparison with other grafting techniques should be the next phase of continuing research efforts.

The survival rates of resin-bonded fixed partial dentures, bonded splints, and bonded combination splints and fixed partial dentures (splints with pontics replacing one or two missing teeth) were determined. For statistical analysis, the splints and splint-prostheses were combined into one group. The average age of all devices combined was 5.7 years. Eleven of 145 resin-bonded fixed partial dentures failed; the survival rate was 83.0%. There was no statistically significant difference between the survival rates of prostheses, whether bonded to prepared teeth or unprepared teeth. Fifteen of 98 splints and splint-prostheses failed. The survival rate of splints and splint-prostheses bonded to prepared teeth (71.6%) was higher than that of splints and splint-prostheses bonded to unprepared teeth (53.6%). To determine the sontinuing relevance of resin-bonded prostheses, the number of instances in which implant dentures could have been used was calculated. Implant treatment would have been possible in only 14 of 98 cases.

This article analyzes different materials incorporated as markers in stents worn by patients undergoing a multiplanar reformatted computerized tomography (MRCT) study of the dental arch for implant placement planning. Forty-five patients were scanned with marked stents. The type of material used for stent markers was evaluated for visibility; ease of analysis in relation to the alveolar ridge crest and adjacent teeth, other markers, or restorations; and relative to its applicability as a presurgical guide. The advantages or disadvantages of each type of marker were discussed. The clinician should be aware of the variety of marker materials available and of the advantages and disadvantages associated with each to optimize the use of the multiplanar reformatted computerized tomography in implant placement planning.

This paper presents a case in which a resorbable collagen membrane and a collagen-based spacemaker and root surface conditioning were used in a guided tissue regeneration procedure. There was no need to disturb the healing potential of the underlying selected cells with an early reentry procedure. Clinical postoperative findings at the time of surgery and in an 18-month follow-up and the differences in density of the mineralized tissues, as detected by standardized series of juxtagingival radiographs and during surgical reentry, showed encouraging results in bone regeneration and soft tissue management.

A review of the literature indicates that one of the major elements of the healing pattern after periodontal surgery is the growth of granulation tissue originating from the periphery of the surgical wound, the periodontal ligament, and the underlying bone. In the past, the periosteum has been given great importance in the process of tissue regeneration; in the current study the authors examined the possible results of removal of the periosteum, which would leave bare bone as the only source of tissue regeneration. The review of a previous study involving perforations to the cortical plate to promote communication between marrow spaces and the receptor bed surface indicated the potential of bone regeneration through the endosteum. The purpose of this article was to stimulate studies devoted to a better understanding of bone potential in periodontal regeneration.