International Journal of Periodontics & Restorative Dentistry, 06/2005

A piezoelectric instrument vibrating in the ultrasonic frequency range was investigated for its potential use in periodontal resective therapy. The rate of postoperative wound healing (baseline and 14, 28, and 56 days after surgery) in a dog model following surgical ostectomy and osteoplasty was the marker used to compare the efficacy of this instrument (PS) with a commonly used carbide bur (CB) or a diamond bur (DB). The surgical sites treated by CB or DB lost bone, in comparison to baseline measurements, by the 14th day, while the surgical sites treated by PS revealed a gain in the bone level. By day 28, the surgical sites treated by all three instruments demonstrated an increased bone level and regeneration of cementum and periodontal ligament. However, by day 56, the surgical sites treated by CB or DB evidenced a loss of bone, versus a bone gain in the PS-treated sites. Thus, it appears that PS provided more favorable osseous repair and remodeling than CB or DB when surgical ostectomy and osteoplasty procedures were performed. Therefore, PS could be regarded as being efficacious for use in osseous surgery.

The purpose of the present study, which used anorganic bovine bone (Bio-Oss) with and without autogenous bone as the augmentation material, was to compare the results of sinus elevation performed without a membrane (control) with the results of sinus elevation performed with either a short-term bioabsorbable membrane (Bio-Gide) or a nonabsorbable membrane (Gore-Tex) with regard to both vital bone formation and implant survival. Sinus lifts were performed on 51 patients (38 unilateral, 13 bilateral) with the delayed placement of 135 implants. Histomorphometric data were obtained at the time of implant placement, 6 to 10 months following the grafting procedure. Vital bone formation was 17.6%, 16.9%, and 12.1%, respectively, for the Bio-Gide, Gore-Tex, and no membrane groups. Of the 135 implants placed there were 3 failures (2 Bio-Gide, 1 Gore- Tex). There was no significant difference between the membrane groups as to vital bone formation and implant survival.

Three case reports are presented that demonstrate the use of full-thickness flap/subepithelial connective tissue grafting for root coverage on the lingual surfaces of the mandibular anterior teeth. This is accomplished using an envelope full-thickness flap technique with intramarrow penetrations at the recipient site. Miller Class I, II, and III gingival recession defects and gingival perforation defects were treated. Complete root coverage was achieved in two Miller Class I gingival recession defects, in one Miller Class II gingival recession defect, and in two gingival perforation defects in areas that exhibited no radiographic evidence of bone loss. Partial root coverage was achieved in two Miller Class III gingival recession defects in an area that exhibited radiographic evidence of bone loss. Although the majority of the exposed root surface was covered in these two Miller Class III defects, about 1 mm of root surface remained exposed, which seemed to closely correspond to the amount of bone loss that was noted radiographically. A grafting technique has been presented that can be used to restore the functional properties of the lingual gingiva of the mandibular anterior teeth by repairing gingival defects and re-establishing the continuity and integrity of the zone of keratinized gingiva. Our clinical impression is that this has made it easier for the three patients presented in this report to maintain the lingual surfaces of the mandibular anterior teeth with routine oral hygiene measures.

The alpha granules of platelets contain various growth factors, which display in vitro and in vivo activities known to be important in wound healing. Biologically active proteins from platelets include platelet-derived growth factor, transforming growth factor-ß, and insulinlike growth factor, as well as other less well-described angiogenic and differentiated protein factors. The purpose of this study was to evaluate histologically and histometrically the new tissue formation on furcation treatment with platelet-derived factor releasate (PR) in beagle dogs. Class II furcations were created in the mandibular premolars of eight adult male beagle dogs. Periodontal regenerative treatments were then performed using collagen sponge graft material with and without the topical application of PR. PR was prepared fresh from blood drawn from dogs before treatments. A histologic evaluation of the effect on new tissue formation was then performed by comparing periodontal tissue regeneration of sites treated with and without PR. Four and 12 weeks after the flap operations, histologic sections were processed and histologically analyzed. The evaluated parameters were bone, cementum and connective tissue attachment regeneration, length of epithelium, resorption, and ankylosis. Histologically evaluated, the regeneration of new cementum was greater at the collagen sponge with PR sites compared to the control sites throughout the entire research period ( P .01). Four and 12 weeks after the flap operations, the amount of new bone in the sites treated with PR was greater than that in the control group ( P .05). These results suggest that collagen sponge graft material with PR promotes new attachment on the periodontal tissue regeneration treatments.

The object of this report was to provide further data supporting the use of short (primarily 7-mm-long) dental implants with a sintered, porous-surface geometry to treat the posterior maxilla using the indirect, osteotome-mediated, localized sinus elevation procedure. Records were available for 104 Endopore implants (Innova) in 70 patients, for whom the majority of implants had been placed in the location of the maxillary first molar. The mean initial subantral bone height before implant placement was 4.2 mm, with a range of 2 to 6.7 mm, and all implants were placed using hand osteotomes and a graft of bovine hydroxyapatite. After an average time in function of 3.14 years, only two implants had been lost, both as a result of unusual circumstances. It is concluded that the use of short, sintered, porous-surfaced implants and localized indirect sinus elevation is a predictable and minimally invasive approach to manage the posterior maxilla with minimal preoperative subantral bone height.

Gingival recession was created in six mongrel dogs. The dogs were divided into two groups based on treatment: group 1-AlloDerm only, group 2-AlloDerm + Emdogain. The histologic results were compared. At the end of the study, the mean values were, for groups 1 and 2, respectively: 0.06 and 0.32 mm for cementum regeneration; -0.75 and -0.86 mm for bone regeneration; -2.15 and -3.11 mm for attachment level; and 4.90 and 5.51 mm for defect extent. The epithelial formation parameter was 2.88 mm in group 1 and 2.15 mm in group 2, which was a statistically significant difference. It could be concluded that Emdogain did not result in beneficial effects when associated with AlloDerm.

Bond strengths between various materials for endodontic post-core buildups are unknown. The study determined the diametral tensile strength of three esthetic post systems bonded directly or indirectly to four core materials, and subsequent scanning electron microscopy was performed on the fractures. Cylindric core buildup was made around the parallel-sided section of the posts using a custommade jig. Strength was tested after 14 days. A significant difference was found between the control group and the other groups ( P = .0001). SEM observations were in agreement with the results. Apart from the control group, the results suggested that directly and indirectly performed post-core buildups have similar diametral tensile strength values.

Two failing implants were removed for prosthetic reasons from the maxilla of a 60-year-old woman. The implants were clinically immobile but presented clear signs of peri-implant mucositis and bone destruction. One of the two implants was harvested together with the surrounding bone and analyzed histologically. The implant was threaded and consisted of three distinct components screwed together in a telescopic fashion. Histologically, bone loss reached the fourth thread, while apical to the fourth thread, osseointegration between the host bone and the implant surface was recognizable. The implant parts were not completely seated into each other, and the resulting gap was colonized by host bone. Newly formed alveolar bone penetrated deep into the implant body cavity and appeared similar in nature to the alveolar bone surrounding the implant. Histologic findings are discussed in reference to the ability of such an implant to withstand biomechanical loading over time.

The purpose of this study was to compare clinical probing measurements with the histologic alveolar bone level in an established baboon model. Implant sites were prepared by removal of all premolars and first molars in 10 adult female baboons (Papio anubis), a total of 120 sites. The resulting edentulous ridges were allowed to heal for 6 weeks. One implant was placed in each site and allowed to heal, after which the implants were removed en bloc. The animals were not sacrificed. Clinical probing from the implant platform to the crest of the bone was performed at the buccal and lingual aspects of each implant at the time of placement and prior to section removal. All measurements were taken with a calibrated probe by a single examiner (ARV). Sections were cut in a buccolingual plane through the long axis of each implant. Histologic slides were digitized for data collection, and histologic measurements were taken at the buccal and lingual aspects from the implant platform to the crest of the bone. The results of the study showed that there were no significant differences between the clinical and histologic measurements. The authors concluded that clinical measurements around dental implants are as reliable as histologic measurements and that the tip of the probe extended to the alveolar bone every time the implant was probed in this model.