Root surface measurements of the mandibular first molar.

The root surface area (RSA) per millimeter of root length was determined for 20 extracted mandibular first molars. The molars were cross-sectioned at 1-mm increments, and each section photographed, projected and measured with a calibrated opisometer. The RSA and per cent RSA were calculated for each 1 mm of root length (1-mm section), the root trunk and the individual roots. Also measured was the location of the root separations from the root trunk, the location of the first detectable root concavity, and the prevalence of "intermediate bifurcation ridges" (IBRs). Mean measurements indicated that the greatest RSA per millimeter of root length was 4 to 7 mm apical to the cementoenamel junction (CEJ) in the area of the furcation. Of the total RSA, 48.7% was located in the coronal 6 mm of a root (mean length, 14.4 mm). Root separation occurred 4.0 mm apical to the CEJ with no tooth having a root trunk longer than 6 mm. Buccal and lingual root concavities were first present 0.7 mm and 0.3 mm apical to the CEJ, respectively. Fourteen (70%) of the 20 teeth had IBRs. According to the mean measurements, the mesial root was larger than the distal root by a ratio of 1.0:0.88. Horizontal attachment loss of 6 mm affecting both the buccal and lingual surfaces of the mandibular first molar would have resulted in a through and through (grade 3) furcation involvement of all the teeth studied.

Microbiology of periapical abscesses and associated maxillary sinusitis.

Aspirate of pus from 5 periapical abscesses of the upper jaw and their corresponding maxillary sinusitis were studied for aerobic and anaerobic bacteria. Polymicrobial flora were found in all instances, where the number of isolates varied from 2 to 5. Anaerobes were recovered from all specimens. The predominant isolates were Prevotella sp., Porphyromonas sp., Fusobacterium nucleatum, and Peptostreptococcus sp. Concordance in the microbiological findings between periapical abscess and the maxillary sinus flora was found in all instances. However, certain organisms were only present at one site and not the other. Five beta-lactamase-producing organisms were present in the five specimens. These data confirm the importance of anaerobic bacteria in periapical abscesses and demonstrate their predominance in maxillary sinusitis that is associated with them.

A comparison of polylactic acid granules and decalcified freeze-dried bone allograft in human periodontal osseous defects.

The purpose of this study was to compare the effectiveness of polylactic acid (PLA) granules as an alloplastic grafting material to that of decalcified freeze-dried bone allograft (DFDBA) and a flap procedure for debridement without graft (FPD) when treating periodontal intrabony defects. Ten patients presenting with advanced adult periodontitis, including at least 3 similar periodontal osseous defects (2- and 3-walled), comprised the study group. After completion of a hygienic phase of treatment, measurements were made with calibrated periodontal probes and stents to determine soft tissue recession, probing pocket depths, and probing attachment levels. Each defect was surgically exposed and hard tissue measurements were obtained. Defects were treated with one of the 3 methods above chosen randomly prior to the surgical appointment. Six months postsurgery, soft tissue measurements were repeated and all sites were surgically reentered to obtain hard tissue measurements. All surgical sites healed without clinical complication. The initial pocket depths and initial depth of osseous defects were compared between the groups using ANOVA and no significant differences were found. A mean osseous defect fill of 0.4 mm (11.2%) occurred with the flap procedure for debridement, 3.0 mm (65%) with DFDBA, and 0.1 mm (2.2%) with PLA. Mean crestal bone loss was 1.30 mm for FPD, 0.60 mm for DFDBA, and 1.55 mm for PLA. No statistically significant differences were found in soft tissue recession between groups or in the osseous defect measurement between PLA and FPD. A statistically significant improvement (P < 0.001) was found in the fill of the osseous defects when using DFDBA compared to the initial defect depth and to the other 2 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative SEM study on the effect of acid etching with tetracycline HCl or citric acid on instrumented periodontally-involved human root surfaces.

This study compared the surface characteristics of periodontally diseased single-rooted human teeth extracted after treatment with either tetracycline HCl or citric acid solutions. The study group was comprised of 30 teeth from 22 patients with advanced periodontal disease extracted before the start of periodontal therapy. Diseased surfaces were identified, outlined, and root planed by hand curet or finishing bur. The teeth were sectioned and solutions of tetracycline HCl or citric acid (pH 1) were applied to the surfaces with cotton pellets for 5 minutes. Extracted teeth were processed and root surface samples then examined by scanning electron microscope. The surfaces of both acid-treated sets of specimens differed considerably from specimens treated with root planing alone, regardless of root planing method. Acid-treated specimens exhibited dentinal tubules exposed by the removal of the smear layer, surfaces devoid of the debris normally present in root planed-only specimens, and the dense network of collagen fibers that make up the dentin structure. Although differences were seen in surface depressions and fiber-like structures among some specimens, the tetracycline HCl and citric acid solutions produced comparable morphologic characteristics.

Interpretation of linear and computed tomograms in the assessment of implant recipient sites.

Tomography is a radiographic process that produces cross-sectional images of bony structures within the body. The purpose of this study was to evaluate the accuracy of diagnostic measurements made by dental implant team members from linear tomograms of human cadaver mandibles. Five partially edentulous cadaver mandibles were radiographed using linear tomography (LT) and computer-assisted tomography (CT). From the tomograms, each of four team members traced the perceived outer circumference of the mandible and the inferior alveolar canal. Tomogram tracings were compared to each other and to the equivalent CT cross-sectional image to determine the precision of the measurements. One mandible was sectioned to verify the accuracy of the CT images. Repeated measures analysis of variance of the measurements made from the LT and CT scans showed significant statistical differences between team members. Multiple cross-sectional views facilitated identification of the inferior alveolar canal in the majority of CT scans, whereas image blurring inherent to LT resulted in the inability of team members to identify the canal in 14% to 50% of the images. Volume averaging within the CT slice aperture was found capable of producing a magnification error of short dense objects. CT and LT must both be interpreted cautiously because of innate technique objects. CT and LT must both be interpreted cautiously because of innate technique pecularities that can lead to measurement errors. The wide variation in interpretation of the linear tomograms and frequent inability to identify the inferior alveolar canal made this technique less valuable than the reformatted CT when planning dental surgical procedures.

CO2 lasers and temperature changes of titanium implants.

Lasers may be useful in uncovering submerged implants or in removing contaminants from "ailing" implants. The purposes of this study were to record temperature changes at the bone-titanium implant interface when using a CO2 laser to: 1) uncover the implant at second stage surgery; and 2) "decontaminate" exposed implant threads. Scanning electron microscopy (SEM) was used to characterize surface changes of lased implants, both uncontaminated or contaminated with blood or saliva. In part one, 28 titanium implants, measuring 3.75 mm by 7 to 20 mm, were placed into room temperature, fresh, resected pig mandibles and covered with a flap of gingiva. The overlying tissue was removed with a CO2 laser at different power levels. Bone-implant interface temperatures were measured with a thermocouple near the top of the implant, and 5 to 7 mm apical to the osseous crest. The effects of implant size, power level, tissue thickness, and operation time were evaluated. In part two, 5 mm by 4 mm bony dehiscences were created on 3 implants in one mandible and the exposed fixture threads lased at varying times and power levels. The results from part one showed temperature increases at the top thermocouple ranged from 4.2 to 16.8 degrees C and increases at the bottom thermocouple ranged from 2.0 to 11.5 degrees C. The results from part two showed temperature increases at the top thermocouple ranged from 1.2 to 11.7 degrees C and increases at the bottom thermocouple from 0.0 to 5.0 degrees C. If baseline ambient temperatures are 37 degrees C, then the temperature at the bone-implant interface might exceed 50 degrees C. SEM revealed no gross surface changes in lased uncontaminated implants, but laser treatment alone of contaminated implants failed to completely remove saliva or blood. Further study is needed regarding temperature increases and surface changes induced by lasers that may adversely affect osseointegration.

Comparative study of collagen and expanded polytetrafluoroethylene membranes in the treatment of human class II furcation defects.

The purpose of this study was to compare the changes in clinical attachment when either a non-resorbable ePTFE membrane or an absorbable collagen membrane was used as a barrier during surgical treatment of class II molar furcation defects. Thirteen patients, mean age 43.2 years, with two comparable class II molar defects were treated using a split mouth design. Pre-surgical standardized probings were made using an automated probe at a constant force of 25 grams. Four to 6 weeks after initial therapy, the furcations were surgically debrided, the membranes placed to occlude separate furcation defects in each patient, and the sites closed. The ePTFE membrane was removed 6 weeks after placement. Six months postsurgery, the clinical measurements were repeated. Student t test was used to compare the results. There were no significant differences in the mean initial measurements between the treatment groups. The mean decrease in vertical probing depth was 1.40 +/- 1.68 mm for the collagen treated sites and 1.07 +/- 0.81 mm for the ePTFE treated sites. The decrease in horizontal probing depth was 1.49 +/- 1.97 mm for the collagen treated sites and 0.79 +/- 2.16 mm for the ePTFE treated sites. No significant differences were found between any of the clinical parameters measured. Based on the results of this short-term clinical study, the absorbable collagen membrane was statistically equivalent to the non-resorbable ePTFE membrane in the clinical resolution of class II furcation defects.

Clinical evaluation of guided tissue regeneration in the treatment of maxillary class II molar furcation invasions.

This investigation assessed and compared the clinical efficacy of combined open flap debridement/occlusive membrane therapy versus open flap debridement therapy alone, in the treatment of maxillary periodontal furcation defects. Seventeen patients presenting with advanced adult periodontitis, including at least one pair of Class II maxillary furcal defects, comprised the study group. Following completion of a hygienic phase of treatment, measurements were made with calibrated periodontal probes to determine soft tissue recession, probing pocket depths, and attachment levels. Each pair of furcation defects was surgically exposed and hard tissue measurements obtained. Defects were treated with either open flap debridement and a polytetrafluoroethylene periodontal membrane or open flap debridement alone. Membranes were removed at 4 to 6 weeks. Six months postsurgery, soft tissue measurements were repeated and all sites were surgically re-entered to obtain hard tissue measurements. No statistically significant differences were found in recession, probing depth reductions, clinical attachment gains, or resorption of alveolar crest height between test and control groups. Results for these parameters were inconsistent and unpredictable. Statistically significant improvements were found, however, in horizontal open probing attachment (HOPA) and vertical open probing attachment (VOPA) between experimental and control sites. The GTR procedure as used in this study likely has limited application as a therapeutic modality for Class II furcations of maxillary molars. Modifications or improvements in the procedure may result in more predictable healing of these lesions.

The use of a synthetic skin substitute as a physical barrier to enhance healing in human periodontal furcation defects: a follow-up report.

The purpose of this investigation is to compare the clinical response of guided tissue regeneration using a synthetic wound dressing with open flap debridement versus open flap debridement alone in the treatment of human furcation defects. The study group was composed of 19 patients with moderate to advanced adult periodontitis and at least one bilateral pair of Class II molar furcation defects. After the hygiene phase of therapy was completed, measurements were made with calibrated periodontal probes of the clinical attachment levels, probing depths, and soft tissue recession. Paired sites were randomly selected for treatment with either open flap debridement alone (control) or open flap debridement and placement of the synthetic wound dressing over the furcation (experimental). At the time of surgery, measurements of vertical and horizontal open probing attachment were recorded. The dressing was removed 5 to 6 weeks post-surgery. The sites were reentered at 6 months to evaluate healing and to repeat all measurements. Statistical comparisons using the Wilcoxon Sign Rank Test were made between the control and experimental sites. The results of 19 pairs of Class II molar furcation defects reveal statistically significant differences between the experimental and control sites in attachment levels, probing depths, and horizontal open probing attachment. These differences were of such small magnitude that they may not be clinically relevant. There were no other significant differences for any other clinical parameter, and none of the furcations in either group was completely closed.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical evaluation of the use of decalcified freeze-dried bone allograft with guided tissue regeneration in the treatment of molar furcation invasions.

The purpose of this study is to evaluate the potential of decalcified freeze-dried bone allograft (DFDBA) combined with a barrier material in the treatment of human molar furcation defects (experimental) as compared to the barrier technique alone (control). Fifteen pairs of Class II or III furcation invasion defects comprised the study group. Measurements with calibrated periodontal probes were made to determine soft tissue recession, probing depth, and attachment levels. Defects from each pair were randomly selected to be treated with an expanded polytetrafluoroethylene membrane (e-PTFE) and DFDBA or the membrane alone. Additional measurements were made during surgery to determine crestal resorption, and vertical and horizontal open probing attachment. The membrane was removed 4 to 6 weeks post-insertion. Six months post-treatment, each site was surgically reentered and measurements repeated. Following either treatment, recession was minimal with statistically significant improvement in probing depth reduction and clinical attachment level gain favoring the combined technique. Hard tissue changes were comparable for alveolar crestal resorption, however, there was a distinct difference, statistically, for both horizontal and vertical bone repair favoring the use of the demineralized bone graft in combination with the e-PTFE membrane.

Bone grafting and guided bone regeneration for immediate dental implants in humans.

This study evaluated bone regeneration and osseointegration of hydroxyapatite (HA) coated and titanium plasma sprayed (TPS) implants placed in sockets immediately after extraction in 36 adults, mean age 55.2 years (range 26 to 81 years). Twelve TPS and 10 HA-coated implants in 20 patients were grafted with demineralized freeze-dried bone allograft (DFDBA), covered with a barrier material, and the facial flap coronally positioned to attain primary closure (experimental). The remaining 11 TPS and 10 HA-coated implants were placed similarly, except that no DFDBA was used (control). Osseous structures were measured at the initial placement and 6-month re-entry surgeries. At the 6-month re-entry, all implants placed were clinically osseointegrated. Bone resorption at the most coronal socket crest was -1.53 mm for the grafted group and -1.59 mm for the control group. Crestal bone apposition of 1.39 mm was noted at the most apical socket crest (ASC) for the grafted group, whereas crestal resorption of -0.11 mm was noted in the ungrafted control group (P < 0.02). Bone fill from the base of the deepest osseous defect was 5.68 mm for the grafted group and 3.18 mm for the control group (P < 0.04). Complete resolution of osseous defects occurred at 15 of 22 sites in the grafted group and at 9 of 21 sites in the control group. Clinical exposure of the barrier material and a subsequent inflammatory response at 27 of 43 sites, requires removal of the material prior to the 6-month re-entry and was associated with significantly more bone loss at the ASC sites (P < 0.01). There was no significant difference for any of the parameters when comparing the TPS with the HA-coated implants.

Small versus large particles of demineralized freeze-dried bone allografts in human intrabony periodontal defects.

Various particle sizes of demineralized freeze-dried bone allograft (DFDBA) are currently used to treat patients with periodontal osseous defects. However, the effect of particle size on the healing of human intrabony periodontal defects is unknown since there have been no direct clinical comparisons. The purpose of this study was to compare the bony defect resolution obtained using two different particle size ranges of DFDBA. Cortical bone from a single donor was processed and ground to final particle sizes of 250 mu to 500 mu or 850 mu to 1,000 mu using an analytic mill. Paired interproximal intrabony periodontal defects in 11 patients were grafted with DFDBA. Soft and hard tissue measurements were made using an electronic constant-force probe at the initial and reentry surgeries. Treated sites in 10 patients were reevaluated by reentry approximately 6 months postoperatively. Mean bony defect fill was 1.66 mm for the large particle group and 1.32 mm for the small particle group. There was no statistically significant difference in bony fill between defects grafted with the different particle sizes of DFDBA when used in humans.

Thick free gingival and connective tissue autografts for root coverage.

Studies have shown partial to complete root coverage of denuded root surfaces with the use of thick free gingival autografts (FGGs) or subepithelial connective tissue autografts (CTGs). The purpose of this study was to determine which technique would result in more predictable root coverage of Miller Class I and II marginal tissue recession defects. Paired defects in 10 patients were randomly selected for treatment with either the FGG or the CTG. With stents as reference points, soft tissue recession was measured with a calibrated probe presurgically and 3 and 6 months postsurgically. No significant differences between paired sites in presurgical defect dimensions were found. One patient was dropped from the study for noncompliance with postoperative instructions. The mean percentage of root coverage for the CTG 3 and 6 months postsurgery for the remaining 9 patients was 78% and 80%, respectively. The mean percentage of root coverage for the FGG was 43% at both periods. The difference in root coverage between the 2 techniques was significant (P < 0.03). Complete root coverage was gained in 5 of 9 CTGs but only in one of 9 FGGs. Both techniques resulted in a significant improvement in keratinized tissue and probing attachment level, with most of the changes having occurred during the first three months postoperatively. Results suggest that the CTG may provide a greater percentage of root coverage than the FGG and that both techniques will effectively increase the width of keratinized tissue.

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.

Evaluation of the immunogenicity of freeze-dried skin allografts in humans.

A study was undertaken to evaluate the antigenic potential of allogeneic freeze-dried skin (FDS) when used as a grafting material and to examine the clinical results when FDS is used for the correction of mucogingival problems in humans. FDS was obtained from an HLA-tissue-type donor according to Navy Tissue Bank protocol. Allogeneic FDS grafts were performed to correct mucogingival problems. In addition, periosteal fenestration was used in conjunction with approximately one-half of the grafts. Documentation with a standardized periodontal probe consisted of clinical measurements taken preoperatively and 8 weeks postoperatively. Blood samples were drawn prior to and at 1, 2, 3, 5, and 8 weeks postsurgically. Testing of blood samples for anti-HLA antibody was performed by use of a modified microcytotoxicity assay. Thirty-one patients received 36 FDS grafts involving 148 tooth sites. The FDS allografts resulted in a significant (P < 0.001) increase in the width of attached-type tissue (mean gain = 3.80 mm). Clinically, there was no sign of graft rejection, and serologically, all serum samples tested were nagative for the presence of anti-HLA antibody. FDS grafts used for the treatment of mucogingival problems in humans are nonimmunogenic as evaluated for anti-HLA antibody. The surgical procedure performed using FDS as a graft material resulted in a significant increase in the width of attached-type tissue.

The potential attachment area of the maxillary first molar.

The assumption that the palatal (PAL) root of maxillary molars has significantly greater attachment area than either the mesiobuccal (MB) or the distobuccal (DB) root was tested by documenting the root surface area of the individual roots and root trunks of 20 extracted maxillary first molars. Each molar was cross sectioned every millimeter, and the circumference of each root and root trunk section was measured with a calibrated opisometer. Mean circumferential measurements from each 1-mm section were summed to give the surface area for each root and root trunk. The DB root had significantly less surface area than either the MB or PAL root or the root trunk. There was no significant difference between the surface areas of the MB and PAL roots. The surface area of the root trunk, which was significantly greater than that of any of the three individual roots, averaged 32% of the total root surface area of the maxillary first molar.

Comparison of DNA probe and ELISA microbial analysis methods and their association with adult periodontitis.

The purposes of this study were two-fold: to compare the DNA probe and enzyme linked immunosorbent assay (ELISA) microbial identification tests and correlate the levels of microorganisms with adult periodontitis. A single plaque sample were taken from each of 2 sites in 52 patients. Twelve of these patients were also sampled during and after treatment. The experimental site had clinical indicators of disease (bleeding on probing, probing and attachment loss of > or = 6 mm) and the contralateral site (control) was clinically healthy. A total of 176 plaque samples were collected, divided, processed, and sent for both types of quantitative microbial analyses. All of these samples were used to compare the DNA probe and ELISA methods while only the initial 104 pretreatment sites were used to correlate microorganisms/method with clinical indicators of adult periodontitis. DNA probes were used to assay for A. actinomycetemcomitans, P. gingivalis, P. intermedia, E. corrodens, F. nucleatum, T. denticola, and C. rectus. An ELISA utilizing monoclonal antibodies was used to assay for P. gingivalis, E. corrodens, T. denticola, and C. rectus. Comparison of the two methods revealed that the ELISA test identified P. gingivalis and C. rectus significantly more often than the DNA probe method and that T. denticola was detected more frequently with the DNA probe. The sensitivities and specificities varied widely among organisms and by test. P. gingivalis, as identified by ELISA, had the highest degree of sensitivity and specificity (0.90 and 0.82 respectively) to clinical indicators of adult periodontitis.

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.

Clinical survey of fractured teeth.

Through a standardized procedure using clinical examination, interviews, and dental history, this 2-year study documents 100 cases of tooth fracture in 98 patients. For comparison, pertinent information was also recorded for more than 2,000 teeth in a randomly selected sample population. Two chief types of fracture were found: incomplete crown-root fractures and root fractures associated with earlier endodontic therapy.

Changing concepts. The effects of occlusion on periodontitis.

Despite volumes of publications on the theory of occlusion, occlusal design, and equilibration techniques, there have been few well-designed human studies directed at answering the question does occlusal trauma modify the progression of attachment loss in periodontitis. The articles reviewed indicate that occlusal forces can cause changes in the alveolar bone and periodontal connective tissue both in the presence and in the absence of periodontitis. These changes can affect tooth mobility and clinical probing depth. Although occlusal forces do not initiate periodontitis, results are inconclusive as to if or how these forces affect attachment loss owing to plaque-induced inflammatory periodontal disease. Although some studies reported a relationship between increased attachment loss and tooth mobility, others found no relationship between attachment loss and abnormal occlusal contacts. Tooth mobility results from a variety of factors, including alveolar bone loss, attachment loss, disruption of the periodontal tissues by inflammation, widening of the PDL in response to occlusal forces (physiologic adaptation), PDL atrophy from disuse, and other processes that effect the periodontium. Therefore, any relationship found between tooth mobility and progressing periodontitis does not necessarily implicate or defend occlusion as a cofactor in the progression of inflammatory periodontal disease. Periodontitis can be treated and periodontal health maintained without occlusal adjustment and in the presence of traumatic occlusal forces. Statistically greater gains in clinical periodontal attachment level have been reported, however, when occlusal adjustment was included as a component of periodontal therapy. The extent to which this is clinically meaningful is unclear. Once periodontal health is established, occlusal therapy can be used to reduce mobility, to regain bone lost owing to traumatic occlusal forces, and to treat a variety of clinical problems related to occlusal instability and restorative needs. The clinician's decision whether or not to use occlusal adjustment as a component of periodontal therapy should be related to an evaluation of clinical factors involving the patient's comfort and function and not based on the assumption that occlusal adjustment is necessary to stop the progression of periodontitis.