International Journal of Periodontics & Restorative Dentistry, 04/1998

This study evaluated the clinical, radiographic, and histologic response to Bio-Oss porous bone mineral when used alone or in combination with Bio-Gide bilayer collagen membrane in human periodontal defects. Four intrabony periodontal defects were treated: two received Bio-Oss alone and two were treated with a combination of Bio-Oss and Bio-Gide. Radiographs, clinical probing depths, and attachment levels were obtained preoperatively and 6 to 9 months postoperative, and teeth and surrounding tissues were biopsied. Both treatments significantly improved clinical probing depths and attachment levels, and the radiographic appearance suggested osseous fill. Histologic evaluation revealed that both treatments produced new cementum with inserting collagen fibers and new bone formation on the surface of the graft particles; this regenerative effect was more pronounced using the Bio-Oss/Bio-Gide combination, which resulted in 7 mm of new cementum and periodontal ligament and extensive new bone incorporating the graft. The membrane was intact at 7 months and partially degraded by 9 months after treatment. This human histologic study demonstrates that the prous bone mineral matrix used has the capacity to stimulate substantial new bone and cementum formation and that this capacity is further increased when the graft is used with a slowly resorbing collagen membrane.

This study examines a protocol for achieving successful osseointegration in immediately loaded implants. With an atraumatic surgical technique and an acceptable biomaterial for implant placement, in certain cases adequate splinting of implants may sufficiently shield the bone-implant interface from functional overload and prevent micromovement from exceeding the allowable limits for successful osseointegration. Two successful cases are presented in which titanium root-form implants were immediately loaded for the support of fixed restorations in the maxilla and the mandible. The authors conclude that for a distinct patient population, immediate loading of multiple, splinted implants may prove to be a valuable adjunct to therapy.

This case report describes possible etiology, treatment, and 2-year outcome of a complicated case of gingival recession in the mandibular anterior dentition. Deep, cleftlike Miller Class I and II recessions at both mandibular canines and all incisors were treated using subperiosteal connective tissue grafts and coronally repositioned flaps. During surgery it was noted that the facial aspcts of the roots had lost bone near the apex. After surgery, profound alterations of gingival dimension occurred. Mean gingival thickness increased from 0.87 ± 0.20 mm to 2.58 ± 0.65 mm, and width of keratinized tissue increased from 1.34 ± 0.79 mm to 4.80 ± 0.97 mm. Periodontal probing depths increased from 1.06 ± 0.33 mm to 2.74 ± 0.81 mm, and depthof the recessions was reduced by 56% ± 5%. Gingival thickness and periodontal probing depth remained stable over the 2 years of observation. Gingival width decreased and the mucogingival border moved a mean 2.5 mm coronally. Creeping attachment resulted in a 74% ± 24% coverage of recession after 2 years and a gain in clinical attachment of 1.79 ± 1.56 mm. The present observa tions point to long-lasting, continuous alterations in the mucogingival region following periodontal surgery in a case of cleftlike Class II recessio

A case report is presented in which a titanium implant was placed into a defect resulting from the extraction of an impacted tooth; the defect was filled with demineralized freeze-dried bone allograft particles without a membrane barrier. After a 6-month healing period the bone defect had completely healed and the tissue present had macroscopic features similar to mature bone. Histologic examination of this tissue showed that, in all demineralized freeze-dried bone allograft particles, mineralization nodules were scattered inside the demineralized bone; in the areas where the mineralization nodules were present, osteocyte lacunae could be observed. In the case presented, significant new vital bone formation was observed 6 months after placement of a demineralized freeze-dried bone allograft.

Six block grafts harvested from the mandibular symphysis were used to augment partially atrophied ridges. Three maxillary defects and three mandibular defects were treated in five patients. Autologous bone grafts from the chin were stabilized in the recipient sites with resorbable pins and no membranes were used over the grafts. Healing proceeded without complciations. At 3 to 4 months the external cortical surface of the grafts progressively resorbed and the profiles of the pins protruded from underneath the buccal tissue that covered the a ugmented areas. However, the pins never perforated the tissue and they were resorbed macroscopically within 4 to 6 months. At 6 months the areas treated showed successful ridge augmentation and, when exposed for stage 2 surgery, remnants of the pin holes on the external surface of the repaired defects were detected. Radiographic evaluation of the block grafts was performed at 3 and 6 months and histologic specimens were obtained at 6 months; the specimens demonstrated incomplete pin resorption and encapsulation. A severe foreign-body reaction was detected in one case. The presence of an acellular bone matrix in certain sections and a normal bone pa ttern with a cellular component in others was a consistant finding. ITI endosseous implants were placed with excellent primary stability in all treated cases.

Masticatory mucosa around implants may be useful to enhance esthetics and/or plaque control. This study proposes simplified guidelines for maintaining or obtaining a minimal amount of masticatory mucosa around submerged implants in cases of partial edentulism, and for keeping the need for additional surgery to a minimum. Free gingival grafts were used in the mandibular arch when the width of buccal masticatory mucosa was less than 2 mm. The width of masticatory mucosa expected to be available for attachment to the bone surface buccal to implants was estimated by measuring the distance between the emergence of the implant from bone and the mucogingival junction. When this distance was 3 mm or less, the use of an apically positioned flap for implant exposure was preferred over gingivectomy. The amount of masticastory mucosa buccal to implants was measured 2 weeks, 6 months, and 12 months after implant exposure. In no case was the width of masticatory mucosa less than 2 mm at 1 year. Therefore, this protocol is recommended for the treatment of cases where the presence of an adequate amount of masticatory mucosa is necessary to ensure a satisfying appearance or is useful for facilitating oral hygiene.

Bioresorbable barriers have been recently introduced in clinical practice for guided tissue regeneration therapy. One of these is the Guidor matrix barrier, which is made of amorphous polylactic acid softened with a citric acid ester to increase malleability and facilitate clinical handling. The advantages of the bioresorbable barrier include: the elimination of second surgery; better handling and adaptation around the totoh and over the bone; and integration of the connective tissue of the flap with the barrier, preventing epithelial migration, gingival recession, and pocket formation. In the case of matrix exposure the material disappears within 6 to 8 weeks. The purpose of this report is to present the clinical application of the Guidor matrix barrier in the treatment of two- or three-wall intrabony defects that were followed up for more than 1 year. The evaluation included soft tissue changes using clinical parameters and ahr d tissue changes using nonstandardized digital subtraction radiography. In the authors' opinion, the incorporation of a bioresorbable barrier in guided tissue regeneration therapy represents a significant improvement in the treatment of intrabony defects.

A narrow mandibular posterior alveolar ridge was modified by the use of a soft tissue expander to generate adequate tissue for graft coverage. The principles of osteoperiosteal flaps were combined with guided bone regeneration techniques for an optimum amount of bone at the site.