Effect of early exposure on the integration of dental implants: Part 2--Clinical findings at 6 months postloading.

Implant exposure during initial healing after placement has been considered important in both implant integration and postloading effects. This study evaluated the effect of early implant exposure on the clinical findings prerestoration and 6 months postrestoration. Forty-eight implants (24 CPTi and 24 Ti-13-13) were placed in maxillary and mandibular posterior sites in six baboons. Implant exposure was evaluated for 24 of the submerged implants at placement and at each weekly visit for 3 weeks after implant placement. The crestal bone level at maxillary posterior sites was measured at 6-month uncovering, and mandibular sites were measured at 3-month uncovering. All sites were again measured 6 months after restoration placement. Periotest readings were recorded at implant uncovering and again 6 months postloading. Arbitrary groupings of the Periotest values were assigned as good = -7 to -1; guarded = 0 to +2; and poor = +3 to +27. At 6 months postloading, there were no statistical differences between CPTi and Ti-13-13 for change in crestal bone height in either arch. The mean change in maxillary crestal bone height varied from a 0.59- to 1.35-mm loss. The differences between the mean exposed and nonexposed changes were not statistically significant The mean change in mandibular crestal bone height varied from a 0.25- to 0.88-mm loss. Changes in crestal bone height for nonexposed sites from 3-month implant uncovering to 6 months postloading were statistically significant at the mesial, buccal, and lingual aspects. The mean change for the nonexposed distal aspect approached significance. The differences between the mean exposed and nonexposed changes were not statistically significant. The overall percentage of maxillary implants in the good category for nonexposed sites decreased by 41% from uncovering to 6 months after loading, while no change occurred for exposed sites; the percentage of implants in the good category was comparable for early exposed and nonexposed sites (57% and 59%, respectively). At 6 months after loading, the percentage of implants in the good category was more favorable for early exposed (88%) than nonexposed sites (50%). A one-stage implant approach should provide similar postloading clinical results as the two-stage surgical approach.

Persian leopard (Panthera pardus) attack in Oklahoma: case report.

The authors report a fatal case of a Persian leopard (Panthera pardus) attack in an animal sanctuary in Oklahoma. The victim was a 53-year-old Costa Rican woman who was attempting to feed the animal when she was attacked and killed. Autopsy, radiography, fingerprint analysis, microbiologic cultures, and dental impressions were used to evaluate the case. These simple techniques can be applied to similar cases involving wild and domestic animal attacks.

A morphometric evaluation of allograft matrix combinations in the treatment of osseous defects in a baboon model.

Recent and ongoing research efforts have been made to increase the efficacy of biomaterials as structural fillers during in vivo bony reconstructions. Although the selection of the possible material choices has grown, a biomaterial that can be physically molded to the defect/void space as well as offer biomimetic tissue regeneration has yet to be made available. With the potential success of demineralized freeze-dried bone allografts (DFDBA) combined with tendonous collagen as an effective filling material, further research should help to elucidate its use. The purpose of this study was to evaluate the regenerative healing response of five allograft mixtures via the morphology of filled, periodontal defects. Critical size mandibular and maxillary osseous defects were surgically created in six adult baboons. The filling response of four combinations of DFDBA and tendon collagen was compared with an all-collagen graft after 3 months of implantation. The overall results indicate that all combinations of DFDBA and collagen provided a better fill response than the all-collagen matrix (P < 0. 05). Statistically, however, all of the combinations were similar (P > 0.05) with a 60:40 collagen to DFDBA mass ratio resulting in the largest defect fill response.

Effect of early exposure on the integration of dental implants in the baboon: Part 1--Clinical findings at uncovering.

There has been increased discussion on the advantages of a one- versus a two-stage surgical approach in the placement of dental endosseous implants. This study evaluated the influence of early implant exposure on crestal bone height adjacent to the implant surface and Periotest values at uncovering in the baboon. Forty-eight implants (24 commercially pure titanium, 24 titanium alloy) were placed in maxillary and mandibular posterior sites in 6 baboons. Implant exposure was evaluated weekly for 3 weeks after implant placement. The level of bone adjacent to the dental implants was measured at placement from the top of the implant collar to the crest of the bone at the mesial, distal, buccal, and lingual surfaces. The maxillary sites were measured again at a 6-month uncovering, while the mandibular sites were measured at a 3-month uncovering. Periotest readings were also recorded at uncovering. Early implant exposure was more common in the mandible, with the majority occurring by the second week postplacement. There were no significant differences in the crestal bone height changes at uncovering between the pure titanium and alloy implants in either arch. In the maxilla, the changes in crestal bone height were not statistically different between exposed and nonexposed implants at any aspect. In the mandible, the difference in 3-month changes between exposed and nonexposed implants was significant for the distal, buccal, and lingual aspects. The overall percentage of implants with a Periotest reading in the "good" category was greater for the nonexposed sites as compared to exposed sites. The results of this study suggest that the two-stage surgical approach results in a better clinical outcome as compared to the one-stage approach in the baboon model.

Effect of unintentional exposure of 2-stage implants upon subsequent osseointegration: histologic findings 6 months postloading.

The purpose of this study was to evaluate the effect of early spontaneous exposure of 2-stage implants upon subsequent histologic bone contact following occlusal loading. As part of a study comparing 2 types of metallic threaded implants, 48 implants (24 CPTi and 24 Ti-13Nb-13Zr) were placed in maxillary and mandibular posterior sites in 6 baboons. Implant exposure was evaluated at time of placement and at each weekly visit for the first 3 weeks, then at 1, 2, and 3 months, and also at 6 months for the maxilla. Block sections were removed 6 months after the implant restoration was placed into function. One third (33%) of the maxillary implants became exposed, while 66.5% of the mandibular implants became exposed, mostly at 1 to 3 weeks. For all maxillary implants, fibrous tissue contact in the unintentionally exposed group (20.0%) was significantly greater than in the group that remained submerged (7.7%). Maxillary implants remaining submerged exhibited more sinus contact. For all mandibular implants, bone contact in the exposed group (38.9%) was significantly greater than in the submerged group (24.3%). Similarly, exposed implants exhibited less fibrous tissue contact. All other parameters in both maxillary and mandibular arches were statistically similar when comparing unintentionally exposed implants to those that remained submerged. This study suggests that accidental exposure of 2-stage implants should result in overall similarities in postloading bone contact to 2-stage implants that remain submerged during the early postoperative healing period.

The use of biodegradable polylactic acid barrier materials in the treatment of grade II periodontal furcation defects in humans--Part II: A multicenter investigative surgical study.

This study evaluated whether differences in design of 3-dimensional polylactic acid barriers (EPi-Guide and Guidor) would influence hard tissue results in the treatment of Grade II furcations in humans. A multicenter study was conducted, using 40 patients with moderate to advanced bilateral chronic adult periodontitis of the mandibular first or second molars. After flap access, debridement, and root preparation, surgical bone level measurements were taken and membranes were placed on a random basis. Surgical reentry occurred at 1 year. Data collected from all 3 investigative centers were pooled and analyzed using an analysis of variance appropriate for a counterbalancing design. Both barrier materials resulted in significant gains of attachment level and defect reduction. The composite reduction in the vertical component of the osseous defects was greater in the sites treated with Epi-Guide as compared to those treated with Guidor; the difference between barriers reached statistical significance (P = 0.02).

Volumetric changes following barrier regeneration procedures for the surgical management of grade II molar furcation defects in baboons: II. Bone, cementum, epithelium, and connective tissue.

In Part I, a computer imaging technique was used to measure the volumetric fill that occurred in surgically created grade II molar furcation defects after they had been treated using the principles of guided tissue regeneration. In Part II, the volumetric fill for each of the specific tissues comprising the defect fill (epithelium, connective tissue, bone, and cementum) was compared. The histologic material consisted of defects treated using one of three types of surgical treatment as well as untreated control sites. All volumetric measurements were expressed as a percentage of the original surgically created defect size, with 100% indicating complete healing of the defect. The results indicate that none of the defects achieved complete healing. Teeth receiving flap debridement had the most overall defect fill (79.50% comprised of 17.13% bone, 35.81% connective tissue, 37.35% epithelium, and 9.71% cementum). Teeth that received a biodegradable barrier showed a mean overall defect fill of 74.98% (7.41% bone, 47.13% connective tissue, 36.20% epithelium, and 9.26% cementum. Sites treated with an exclusion barrier showed 70.75% overall fill (9.63% bone, 40.89% connective tissue, 39.00% epithelium, and 10.48% cementum). The untreated control teeth showed a mean overall fill of 78.70% (5.56% bone, 59.11% connective tissue, 31.06% epithelium, and 4.27% cementum). No significant differences were found among teeth within the same animal and between treatment and controls. The following conclusions were drawn: (1) connective tissue comprised nearly one half of the total fill of the surgically created defects; (2) the percentage of new bone growth was significantly lower than anticipated; and (3) no significant differences were found among the treatment modalities and the untreated control sites for each of the specific tissue types.

Use of biodegradable polylactic acid barrier materials in the treatment of grade II periodontal furcation defects in humans--Part I: A multicenter investigative clinical study.

This study evaluated two bioresorbable polylactic acid barriers (Epi-Guide and Guidor) to determine if design differences were of therapeutic significance in the treatment of Grade II furcation defects in humans. Forty patients with bilaterally matched, Grade II furcation defects in maxillary or mandibular first or second molars were treated in a multicenter study. Comprehensive initial periodontal therapy, followed by defect debridement and root preparation, preceded randomized membrane placement. Data collected from all three investigative centers were pooled and analyzed using an analysis of variance appropriate for a counterbalancing design. Both barrier types produced measurable improvements of clinical probing values. Barrier exposure scores taken through the eighth week postoperative revealed that Epi-Guide was less likely to become exposed than Guidor. The findings of this study, which was conducted over a 12-month period, demonstrated that Epi-Guide and Guidor were comparable as measured by clinical probing determinations.

Volumetric changes following barrier regeneration procedures for the surgical management of grade II molar furcation defects in baboons: I. Overall defect fill.

A computer imaging technique has been advocated for measuring the volumetric fill in furcation defects. Histologic material for this investigation was obtained from an animal study using five adult baboons (Papio anubis). The photographed histology was converted into digitized electronic information, and a computer calculated the overall volume of defect fill for the treated and the untreated control sites. All volumetric measurements were expressed as a percentage of the original surgically created defect size, with 100% indicating complete healing of the defect. The results indicate that none of the defects achieved complete healing. Teeth that had received flap debridement had the most overall defect fill (79.50%). Teeth that received a biodegradable barrier (Epi-Guide) showed a mean overall defect fill of 74.98%, while sites treated with an exclusion barrier (Gore-Tex) showed 70.75% overall fill. The untreated control teeth showed a mean overall fill of 78.70%. A variety of statistical tests revealed no significant differences among teeth within the same animal and between treatments and controls. The following conclusions were drawn: (1) digital imaging technology is a useful research tool for determining the volume of defect fill in surgically created grade II molar periodontal furcation defects in the baboon model; and (2) no significant differences were found among the treatment modalities and the untreated control sites.

The measurement of molar furcation defect fill using digital computer technology--report on a new technique.

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 determining the volume of defect fill in surgically treated Grade II molar furcation defects in the baboon animal model.

Evaluation of the potential of a polylactic acid barrier for correction of periodontal defects in baboons: a clinical and histologic study.

Created periodontal defects in baboons were treated with one of four possible treatment modes: (1) root preparation and Epi-Guide biodegradable polylactic acid barrier, (2) root preparation and Gore-Tex e-PTFE membrane, (3) root preparation only (no barrier), and (4) no root preparation and no barrier (control). Root preparation consisted of hand instrumentation and use of finishing burs. Measurements of gingival recession were recorded from color photographic slides taken weekly for 6 weeks following barrier placement. Block sections were removed from one animal 6 weeks after barrier placement and prepared for histologic evaluation. Significantly more gingival recession was observed at the Gore-Tex sites than at the Epi-Guide sites. There were no significant differences in gingival recession between the Epi-Guide sites and root preparation-only sites or control sites. Both types of barriers were histologically acceptable. At 6 weeks, the Epi-Guide material was present histologically in a partially resorbed state. There was a mild inflammatory reaction in the surrounding connective tissues.

Combination treatment using decalcified freeze-dried bone allograft with guided tissue regeneration in human periodontal defects: two case reports.

The ultimate goal of periodontal therapy should not be limited to the establishment and maintenance of periodontal health. The potential regeneration of the hard and soft periodontal tissues lost to disease also should be considered. Two case reports are presented to demonstrate the potential of guided tissue regeneration for this purpose.

Comparison of a 0.12% chlorhexidine mouthrinse and an essential oil mouthrinse on oral health in institutionalized, mentally handicapped adults: one-year results.

The purpose of this study was to compare the efficacy of a 0.12% chlorhexidine mouthrinse and an essential oil mouthrinse on plaque accumulation and gingivitis in mentally handicapped adults over a one-year period. Twenty-seven institutionalized mentally handicapped adults participated. Gingival index (GI), plaque index (PI), and probing depths (PD) were recorded and an ultrasonic scaling was performed (Baseline 1). GI, PI, and PD were again recorded after 2 weeks (Baseline 2). Patients were then assigned to either the chlorhexidine or essential oil mouthrinse group. The patients rinsed twice daily under supervision with their assigned mouthrinse while maintaining their attempts at daily brushing. GI and PI were recorded at monthly intervals for 12 months, while the PD was recorded only at Baseline 1 and 2 and at 12 months. A paired t-test was used to compare differences between the parameters at Baseline 1 and Baseline 2. A 2-factor repeated measure ANOVA was performed on each parameter after the Baseline 2 evaluation. A statistically significant decrease in the probing depth occurred as a result of ultrasonic scaling; however, no significant changes in the PI or GI occurred. Both mouthrinses produced a significant improvement in the GI after one month. Despite the improvement, the GI was still indicative of disease. Over the 12 months no further significant improvement in the GI occurred. A statistically significant improvement in the PI occurred in the chlorhexidine group at month 1, but returned to Baseline 2 levels over the 12 months. No improvement in the PI occurred in the essential oil group. The probing depths remained the same over the 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Professional prophylaxis and its effect on the periodontium of full-banded orthodontic patients.

The effect of professional prophylaxis on the periodontium was studied in 14 adolescent orthodontic patients while under active treatment using a split-mouth experimental design. A full-banded appliance was used on all of the patients. The following variables were examined: plaque registration, gingival index, gingival migration, and width of the attached gingiva. Professional rubber-cup prophylaxis was performed on the test side of all patients together with reinforced oral hygiene instruction on a monthly basis. Measurements for the plaque registration, gingival index, gingival migration, and the width of the attached gingiva were recorded at the initial visit (baseline records), the 6-month evaluation, and the 10-month evaluation. Monthly registrations were completed for the plaque deposits and gingival inflammation at each of the 11 visits. All measurements were taken at the midfacial surface of the selected teeth. Four conclusions can be drawn from the findings of this study: the presence of an orthodontic appliance did not result in an increase of plaque accumulation or gingival inflammation for the full-banded orthodontic patient; monthly oral hygiene instruction was effective in significantly reducing the amount of visible plaque and gingival inflammation; monthly rubber-cup prophylaxis had a significant effect in reducing the gingival enlargement routinely associated with a fixed orthodontic appliance; and the width of attached gingiva showed no significant change throughout the course of the study.

Evaluation of the immunogenicity of freeze-dried skin allografts in humans: cell-mediated response.

PATIENTS RECEIVING freeze-dried skin (FDS) allografts were evaluated for cell-mediated response by a lymphocytotoxicity test. Eleven patients received single or multiple FDS allografts from a donor typed for human leukocyte antigen (HLA). Heparinized blood samples were drawn before the procedure and at 2, 4, and 8 weeks after grafting. Mononuclear cells were isolated by Ficoll-Hypaque gradients. Cell-mediated lymphocytotoxicity tests were conducted, with mononuclear cells from the FDS allograft recipients used as effector cells. Phytohemagglutinin-stimulated blast target cells of the same HLA type as that of the skin donor were labeled with chromium 51. Lympholysis was evaluated by measuring the amount of 51Cr release after 18 hours' incubation with target/effector cell ratios of 1:100, 1:50, and 1:25. Negative control wells contained target cells alone. Positive control wells contained target cells and effector cells sensitized in vitro against the target cells. Viability of effector cells was tested by trypan-blud dye exclusion and response to phytohemagglutinin. None of the experimental blood samples showed 51Cr release significantly greater than shown by the negative controls. Our findings of no cell-mediated response and the findings of a previous study showing no production of anti-HLA antibody in response to FDS allografts indicate that allogeneic FDS is an immunologically safe material for use in periodontal surgical procedures.

In vitro growth of human gingival fibroblasts on root surfaces of endodontically treated teeth.

Controversy exists over the potential for new connective tissue attachment to dentin of endodontically-obturated teeth following periodontal therapy. The purpose of this study was to determine whether cultured human gingival fibroblasts would grow in vitro on planed dentin surfaces of endodontically-treated teeth. A model similar to that of Aleo et al. was developed using extracted endodontically-treated human teeth. This model consisted of longitudinally sectioning 10 teeth, root planing one section only, and incubating both sections with a suspension of human gingival fibroblasts. Fibroblast growth was determined by staining with neutral red and trypan blue. The criterion for growth was staining of the complete root surface. All root areas with attached periodontal fibers displayed staining, as well as the complete root surface of all planed sections. Unplaned sections did not stain on root areas formerly exposed to the oral environment owing to periodontal disease, a finding consistent with the results of Aleo et al. Our results indicate that root canal therapy does not interfere with in vitro growth of fibroblasts on planed dentin surfaces of endodontically-treated teeth. Extrapolation to a clinical situation would indicate that normal healing may be expected after periodontal surgery on tissues adjacent to root planed endodontically-treated teeth.

Root morphology--clinical significance in pathogenesis and treatment of periodontal disease.

Root morphology is a seldom considered yet extremely important factor in the treatment of periodontal disease. The shape of the roots may contribute to development of periodontal defects by providing an environment favorable to the retention of plaque. The practitioner should periodically review root morphology and give it appropriate importance during planning and treatment. In this study, teeth with representative root anatomy were sectioned and photographed. The photographs are intended as a visual presentation of various root morphologies and their potential implications in the practice of periodontics.