International Journal of Periodontics & Restorative Dentistry, 03/2002

The purpose of this investigation was to examine the clinical and microbiologic effects of apically repositioned flap surgery. Eighteen patients with chronic periodontitis received initial preparation (IP) including scaling and root planing, followed at 3 months by apically repositioned flap surgery at sites with pocket depth > 4 mm. Subjects were monitored clinically and microbiologically at baseline, 3 months after IP, and at 3, 6, 9, and 12 months postsurgery. Clinical assessments of plaque accumulation, gingival redness, suppuration, bleeding on probing, pocket depth, and attachment level were made at six sites per tooth. Subgingival plaque samples were taken from the mesial aspect of each tooth, and the presence and levels of 40 subgingival taxa were determined using checkerboard DNA-DNA hybridization. Significant reductions were seen in mean pocket depth and percentage of sites exhibiting gingival redness and bleeding on probing in both sites that received IP only and in sites receiving IP followed by surgery. Mean attachment level increased significantly for both sets of sites, but the increase was greater at the surgically treated sites. The total DNA probe counts were significantly reduced at sites in both treatment groups. At surgically treated sites, 19 of 40 taxa were significantly reduced posttherapy. At sites receiving IP only, 16 species were significantly reduced over time. While there were some reductions in mean counts after IP in this site group, the major reductions occurred after the surgical phase in these patients, even though these particular sites did not receive surgical therapy. The reduction in pocket depth by surgical means and the associated decrease in reservoirs of periodontal pathogens may be important in achieving sustained periodontal stability.

Many types of osseointegrated implants that are very reliable and supported by scientific medium- and long-term studies are presently available. Often, unfavorable anatomic situations require bone augmentation procedures either prior to or at the same time as implant placement. Some of these procedures present limits. Using versatile implant systems is desirable in cases such as advanced osseointegration, intraoral bone grafts or guided bone regeneration techniques, or major surgical reconstruction with bone grafts from the hip. The aim of this study was to evaluate the efficacy of the Frialit-2 implant in 29 clinical cases of maxillary and mandibular reconstruction using different bone augmentation techniques, and to consider its success ratio through a 1- to 5-year follow-up.

In recent years, considerable attention has been given to the interrelationship of reduction in the bone mass and the possibility of a significant resorption of the alveolar bone. The degree of alveolar bone loss increases with age, and this may be related, at least in part, to the systemic conditions that also encourage the development of osteoporosis. Although numerous studies have documented the possible role of osteoporosis as a deteriorating factor in both tooth loss and mandibular bone resorption, this article underlines how the morphostructural evolution of the edentulous mandible is primarily correlated to mechanical factors as a result of modifications to its function. We will also take into consideration the therapeutic advantages provided by prosthetic rehabilitation on osseointegrated implants, in terms of reinstatement of the loading conditions through patterns of propagation of mechanical forces that are similar to physiologic ones.

The amount of tooth structure removed for various innovative and conventional preparation designs for fixed prosthodontics was quantified. Four Typodont resin teeth representing maxillary and mandibular premolars and molars were prepared in various abutment designs: adhesive, box (A2); adhesive, wing and groove (A3); mesioocclusal or distoocclusal inlay; mesio-occlusodistal inlay (I3); mesio-occlusodistal onlay; partial crown; half crown (only molars); complete crown, 0.8-mm circumferential tapered chamfer (F1); complete crown, 1.0-mm circumferential rounded shoulder; and complete crown, 1.4- mm axial reduction facial shoulder, 0.7-mm lingual chamfer (F3). After tooth preparation (10 per group), the root was separated from the anatomic crown at the cementoenamel junction. Removal of tooth structure was measured by gravimetric analysis in a high-precision balance. Preparations A3 and F3 were assigned as abutments for metal-supported restorations, whereas all other preparations were used for all-ceramic restorations. When the mean structure removal of all teeth tested was compared, the adhesive and inlay abutments were the least invasive preparation designs, ranging from approximately 5.5% (A2) to 27.2% (I3) tooth structure removal. Complete crowns required the most invasive preparations, ranging from 67.5% (F1) to 75.6% (F3) tooth structure removal. The tooth structure removal required for F3 retainers was almost 14 times greater than for an A2 preparation. Tooth structure removal was also influenced by the morphology of the tooth. The first comprehensive tooth preparation design classification system was introduced. The measurement system used in this study provides an accurate method of quantifying tooth structure removal for fixed prosthodontic preparations. The innovative preparation designs studied conserved significant amounts of tooth structure, yielding a better prognosis for the restored tooth.

A 17-year-old boy underwent three cycles of chemotherapy and a subsequent mandibular resection for a Ewing's sarcoma of the left body and ramus. The mandible was immediately reconstructed with a microvascular osteomuscular fibular flap. One year after the mandibular reconstruction, distraction osteogenesis of the anterior portion of the fibula was performed using a Martin distractor according to the Hoffmeister technique. Bone lengthening was achieved at a rate of 1 mm/day by turning the device twice each day for 12 days. Subsequently, we waited for 70 days for bone consolidation to occur. After 6 additional weeks, five Maestro implants were placed into the distracted fibula. Bone specimens were retrieved with a trephine bur during implant placement. Mature bone was present after 70 days and after 6 months. The bone height increase was 12 mm.

The purpose of the present study was to compare the treatment of deep intrabony defects with a combination of an enamel matrix protein derivative (EMD; Emdogain) and a bovine-derived xenograft (BDX; Bio-Oss) to BDX alone. Twenty-four healthy patients, each of whom displayed one intrabony defect, were randomly treated with a combination of EMD + BDX (test) or with BDX alone (control). Soft tissue measurements were made at baseline and 1 year following the therapy. No differences in any of the investigated parameters were observed at baseline between the two groups. No adverse healing response was observed in any of the patients. At 1 year after therapy, the sites treated with EMD + BDX showed a reduction in probing pocket depth (PPD) from 10.0 ± 1.5 mm to 4.3 ± 1.4 mm and a change in clinical attachment level (CAL) from 10.9 ± 2.0 mm to 6.2 ± 1.9 mm (P .0001). In the group treated with BDX, the PPD was reduced from 9.7 ± 2.4 mm to 3.2 ± 0.7 mm and the CAL changed from 10.1 ± 2.3 mm to 5.2 ± 1.2 mm (P .0001). Hard tissue fill was observed radiographically in all defects. Both treatments resulted in significant improvements of PPD and CAL. However, no statistically significant differences in any of the investigated parameters were observed between the test and control groups. Both therapies led to significant improvements of the investigated clinical parameters.

Tissue regeneration after therapeutic manipulations is essential in periodontology, ral surgery, and trauma of the periodontal tissues. Local inflammation because of oor oral hygiene also plays a crucial role in the above situations. Local inflammatory reaction, accompanied by the local production of cytokines, profoundly influences bone turnover and regeneration. Several products of low immunogenicity for augmenting tissue regeneration have been recently proposed as boosters of soft and mineralized tissue regeneration. Among them, Emdogain, an amelogenin derivative of porcine origin, has recently been introduced. Clinical results indicate that this product might be a good additive, producing fast tissue regeneration with no apparent clinical side effects. In contrast, very little is known about its in vivo immunologic effects. A previous study showed that Emdogain does not modify the cellular or humoral immune response in vitro. In the present work, performed in 10 patients, only a slight, nonsignificant activation of the immune system occurred during the first year following Emdogain application. Neither cellular immunity nor humoral immune response was significantly modified. In addition, the in vitro response of the patients' lymphocytes to Emdogain was assayed 2 and 12 months postoperative. We did not find any significant specific lymphocyte transformation in the presence of Emdogain, although lymphocytes could be stimulated by nonselective mitogens. These results indicate the immunologic safety of the agent in vivo, at least after 1 year.

Bio-Oss is natural bovine bone mineral, which has the property of bone conduction. It is recommended to be used in two- or three-walled bony defects with an ample supply of pleuripotential cells. Two cases are reported. The first was an intentional replantation, because of previous trauma, of a hopeless tooth affected with severe periodontitis. The tooth was replanted after complete elimination of granulation tissue. Bio-Oss, together with a guided tissue regeneration (GTR) membrane, was used to enhance periodontal regeneration. After 2 years of follow- up, the replanted tooth was quite stable. In the second case, Bio-Oss, together with bone taken from the retromolar area, was used in a sinus lift grafting procedure after the removal of two supernumerary teeth from the floor of the maxillary sinus. Four months after grafting, an orthodontic treatment was applied to move the two adjacent teeth through the grafted site and align them in the proper position. The clinical results of the two cases were satisfactory.

A histomorphometric study was performed on six retrieved loaded hydroxyapatite (HA)-coated titanium implants.The implants had been clinically functioning in a 50-year-old patient. She originally presented a severely atrophic maxilla that was reconstructed by sinus floor augmentation using autogenous bone from the iliac crest. In spite of good clinical function, because of psychiatric problems, all implants, including some bordering bone, were removed using a trephine bur. Thin ground sections were prepared for histology and used for histomorphometry. The aim of this study was to observe the condition of the calcium phosphate coating after 2.5 years of functional loading, the nature of the bone-to-implant interface, as well as the density of the bone graft around the implants. Intimate and abundant bone-to-implant contact was observed, ranging from 90.4% to 99.8% along the implant surface. Active bone remodeling occurred within all threads, as demonstrated by secondary osteons close to the implant surface. The thickness of the calcium phosphate coating varied from 51 to 88 µm for the loaded retrieved implants, versus 53 to 89 µm for the nonused control implant. All implants showed bone contact including the first thread and up to the smooth titanium neck. Both the nature and thickness of the coating had hardly changed after 2.5 years of loading. The HA-coated implants used achieved excellent osseointegration and must be considered clinically safe and effective in maxillary grafted bone.