International Journal of Periodontics & Restorative Dentistry, 04/2004

A recently developed technology allows evaluation of bone biopsies with 3-D microcomputed tomography (microCT). The present study evaluated the feasibility of application of microCT to the analysis of peri-implant bone tissues. A human bone biopsy containing a titanium screw was analyzed using a microCT scan. The parameters computed by the microCT were bone volume, bone surface, trabecular thickness, trabecular separation, and bone connectivity. Also, the bone-to-implant apposition was measured, and all results were compared with those obtained with standard histomorphometry of the same biopsy. The results of the present study suggest that microCT enables 3-D nondestructive evaluation of bone biopsies containing endosseous titanium implants, also allowing analysis of the bone-implant interface. Measurements of bone-to-implant apposition obtained by microCT were similar to those obtained with standard undecalcified histology.

The purpose of the present case report is to clinically and histologically evaluate the healing of one advanced intrabony defect following treatment with an enamel matrix protein derivative (EMD) combined with a bovine-derived xenograft (BDX) and guided tissue regeneration (GTR). One patient with generalized chronic periodontitis and one advanced intrabony defect was treated with EMD + BDX + GTR. Notches were placed in the root at the level of the calculus and alveolar crest to aid histologic identification of new periodontal tissues. Postoperative healing was uneventful. At the 7-month histologic examination, healing in the intrabony component of the defect was characterized by formation of new connective tissue attachment (new cellular cementum with inserting collagen fibers) and new bone in the intrabony component. The BDX particles were surrounded by bone-like tissue. No direct contact between the graft particles and root surface (cementum or dentin) was observed. Healing in the suprabony defect component occurred through epithelial downgrowth that stopped at the level of the coronal notch. The BDX particles were entirely encapsulated in dense connective tissue, without any signs of bone formation. The present case report shows formation of new attachment apparatus consisting of new bone, cementum, and periodontal ligament in the intrabony component of one human defect treated with EMD + BDX + GTR.

Bone grafting constitutes a vital surgical procedure in the management of severely atrophic mandibles. In this regard, calvarial bone autografts are applied in the reconstruction of wide mandibular defects caused by edentulousness and longterm denture-related resorption. Grafts are used as a framework to augment the residual ridge and provide implant stability for further prosthetic restoration. On the basis that radiographic evidence corresponds to biologic changes in bone response to transplantation and loading, the goal of this article is to document the radiographic assessment of calvarial autologous bone grafts in the recipient site. Panoramic radiographs were used to evaluate bone changes occurring during both the graft healing period and graft adaptation after implant loading. Emerging data show that conventional panoramic radiography may have an effect on the investigation of bone grafts and provide initial information about graft incorporation and adaptation.

The fabrication of a complete-arch maxillary prosthesis has been associated with several prosthetic complications and difficulties. Although it has been reported that phonetics, esthetics, and proper lip support are difficult to achieve, there is a scarcity of literature on the clinical and laboratory procedures necessary to minimize these complications. The current article provides clinical and laboratory steps that may enable the clinician to achieve more predictable restorative results when fabricating a cement-retained, implant-supported, complete-arch maxillary prosthesis.

The use of acellular dermal matrix to correct soft and hard tissue defects involving implants is described through three case reports. Correction of a ridge deformity caused by a root fracture, submerging of an existing implant and correction of recession defects around adjacent teeth, and ridge preservation for implant placement are presented. The use of acellular dermal matrix prevented the need for a second surgical site for donor material and the possible attendant postoperative complications. It also enhanced patient comfort and satisfaction with the procedure. All three cases demonstrated excellent functional and esthetic results for both the patients and professionals involved in the therapy.

The present study evaluated the effect of combining an enamel matrix derivative (EMD) and a bioresorbable membrane (GTR) in the surgical treatment of degree III mandibular furcation involvements. Nine patients with chronic periodontitis, presenting a total of 14 degree III mandibular furcation involvements, were included in the study. Surgical treatment of the defects was randomly assigned: (1) EMD (four defects); (2) GTR (three defects); and (3) EMD and GTR (seven defects). The degree of involvement was assessed prior to surgery and after 6 and 12 months by measuring the probing attachment level in the horizontal and vertical directions at the furcation site. At 6 and 12 months, partial closure of the involvements had occurred in approximately half of the treated furcations, and the vertical probing level consistently improved following all three treatment modalities. The results suggest that all three treatment modalities may improve healing following surgical treatment of degree III mandibular furcation involvements. However, further studies are needed to examine the clinical significance of these results and the histologic characteristics of the healing following application of EMD.

The purpose of the present investigation was to compare the effectiveness of a scaling bur and conventional Gracey curettes in vivo. Ten teeth scheduled for extraction were scaled and root planed thoroughly before extraction. The instrumented areas were observed using SEM. Scaling with a No. 12 fluted carbide bur was more effective in removing debris and plaque than were conventional Gracey curettes. Because of the aggressive nature of the process, a certain learning curve is necessary to get accustomed to bur scaling; otherwise, dentinal hypersensitivity and patient discomfort may be increased.

The goal of this case report is to evaluate the effectiveness of gingival augmentation with an acellular dermal matrix. The acellular dermal matrix was placed on a periosteal bed. Clinically, the procedure did not result in an increase in the amount of keratinized tissue. There was an increase in the tissue bulk, but the importance of this increase is unknown. Histologic evaluation revealed that the acellular dermal matrix did not slough and was involved in healing. Based on this evaluation, the technique of placing an acellular dermal matrix on a periosteal bed does increase the bulk of tissue in the area. However, the procedure does not seem to be an effective method to increase the amount of keratinized tissue.

This study sought to develop and evaluate a radiographic exploration technique (parallel profile radiograph [PPRx]) for measuring the dentogingival unit on the buccal surfaces of anterior teeth, and to provide additional information on the dimensions of the dentogingival unit in humans. In 88 periodontally healthy individuals, a PPRx was made of the maxillary left central incisor. Over these images, the components of the dentogingival unit were measured. PPRx was a highly reproducible exploratory technique. Mean dentogingival measurements on the buccal surfaces of the teeth were 2.05 ± 0.87 mm for distance between the CEJ and bone crest; 2.00 ± 0.72 mm for biologic width; 1.75 ± 0.24 mm for thickness of connective tissue attachment; 1.12 ± 0.24 mm for thickness of free gingiva at its base; 0.45 ± 0.20 mm for thickness of bone plate at crest level; and 1.41 ± 0.62 mm for gingival overlap on enamel surface. A statistically significant relationship was observed between free gingival width and thickness of connective attachment, and the depth of the gingival sulcus. These results corroborate the notion that the dimensions of the dentogingival unit are highly variable in humans. The thicknesses of both the connective tissue attachment and free gingiva, however, showed less variability than did the thickness of the bone crest, distance between CEJ and bone crest, and biologic width. The results suggest that gingival dimensions are correlated to dentogingival unit dimensions.