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Increasing the amount of attached gingiva using a modified apically repositioned flap.

The purpose of this study is to describe a modification in the apically repositioned flap technique. Unlike the original technique, this technique preserves the marginal gingiva thus avoiding the risk of recession. It is recommended in cases where an increase in attached gingiva is desired. This study reports on the results of 54 single buccal areas consecutively treated in 38 healthy patients. The increase in the amount of attached gingiva, the impact on marginal tissue recession, and the impact on probing depth were analyzed. All 54 areas were evaluated at 8 weeks; 21 areas were analyzed for 24 weeks; and 19 areas for a period of 72 weeks. The final measurements were compared to baseline values. The analysis of variance of measurement (ANOVA) shows a significant increase of keratinized and attached gingiva (P <0.001). There was no statistical change in marginal tissue recession (P = 0.370) or probing depth. The results of this study demonstrate that this modification of the apically repositioned flap is effective and efficient for increasing the height of attached gingiva. This surgical procedure produces minor surgical trauma and does not require palatal donor tissue or membrane placement. It is simpler since it is less time-consuming, requires no suturing, and results in an ideal color match of tissue.

Adolescent↗

Alveolar bone height and postcranial bone mineral density: negative effects of cigarette smoking and parity.

BACKGROUND: Our objective was to test the association between cemento-enamel junction, alveolar-crest distance (CEJ-AC, as measured on digitized vertical bite-wing radiographs) and postcranial bone mineral density (BMD) relative to clinical, dietary, and demographic variables. METHODS: Data were collected in a cross-sectional study of 134 postmenopausal women. CEJ-AC distances were determined from digitized vertical bite-wing radiographs. Lumbar spine and proximal femur BMDs were determined from dual-energy x-ray absorptiometric scans. Correlation analysis and Student t tests were used to identify those variables most associated with CEJ-AC distance. The selected variables were modeled with a backward stepwise regression analysis, with CEJ-AC distance as the dependent variable. RESULTS: Parity (number of pregnancies to term), cigarette smoking, and the interaction of lateral spine BMD with cigarette smoking were independent predictors of CEJ-AC distance (P < or =0.05). Statistical models containing these variables accounted for 19% of the variation in CEJ-AC distances. CONCLUSIONS: CEJ-AC distance in postmenopausal women is the result of a complicated interaction of many effects, including but not limited to, parity, cigarette smoking, and skeletal BMD.

Absorptiometry, Photon↗

Selective cyclooxygenase-2 inhibition prevents alveolar bone loss in experimental periodontitis in rats.

BACKGROUND: Prostaglandins are implicated in periodontal bone destruction. We investigated the effect of a non-selective cyclooxygenase (COX) inhibitor (indomethacin-IND) or a type 2 COX inhibitor (meloxicam-MLX) in an experimental periodontal disease (EPD) model. METHODS: Wistar rats were subjected to placement of a nylon thread ligature around the maxillary molars and sacrificed after 7 days. Alveolar bone loss (ABL) was measured in one quadrant as the distance between the cemento-enamel junction and the alveolar bone. The other quadrant was processed for histopathologic analysis. Daily weight and white blood cell count were recorded. Groups were treated subcutaneously for 7 days with either IND (0.5, 1, or 2 mg/kg) or MLX (0.75, 1.5, or 3 mg/kg). Controls received no treatment. Macroscopic analysis of the gastric mucosa was done. The control group did not receive any manipulation, and a non-treated group consisted of rats subjected to periodontitis that received no pharmacological treatment. RESULTS: In the non-treated (NT) group, there was significant ABL, severe mononuclear influx, and an increase in osteoclast numbers. Significant neutrophilia and lymphomonocytosis occurred at 6 hours and at 7 days, respectively, as compared to controls. Significant weight loss persisted until the seventh day in the NT group. Both IND and MLX reduced ABL and histopathologic changes. Neutrophilia and lymphomonocytosis were also significantly reversed. Both IND and MLX induced earlier weight recovery. The stomachs of the IND (1 and 2 mg/kg) groups presented hemorrhage and ulcers, whereas in the MLX-treated groups, there were mild petechiae just in the 3 mg/kg group. CONCLUSIONS: COX inhibition prevented ABL in this experimental periodontal disease model. MLX displays similar efficacy and less gastric damage than IND. MLX may provide a better risk/benefit ratio in the treatment of human periodontitis than non-selective COX inhibitors.

Alveolar Bone Loss↗

Buccal alveolar exostoses: prevalence, characteristics, and evidence for buttressing bone formation.

BACKGROUND: Buttressing bone formation has been described as the development of thickened or exostotic buccal alveolar bone in response to heavy occlusal forces. Little supporting evidence for this model has been found in previous literature, however, and there is little seen on the prevalence or characteristics of buccal alveolar exostoses. METHODS: A sample of 416 selected teeth and investing bone in 52 modern skeletal specimens at the National Museum of Natural History were examined. Two measures of heavy occlusal function--periodontal ligament (PDL) width and occlusal attrition--were analyzed for their relationship to three parameters of buccal alveolar bone (exostoses, lipping, and overall thickness). RESULTS: Buccal alveolar bone enlargements were found in 25% of all teeth examined: 18% were expressed as marginal bony lippings and 7% as buccal exostoses. Exostoses were mainly seen around maxillary molars and bicuspids, especially in males, while lippings were seen in molars, bicuspids, and mandibular incisors, with even gender distribution. When findings were controlled for arch and tooth type, no significant correlations were found between wider PDL spaces or occlusal attrition and exostotic, lipped, or thicker alveolar bone. CONCLUSIONS: These results indicate a lack of anatomic evidence for the theory of buttressing bone formation and suggest that other factors may be of greater importance in the etiology of buccal bone enlargements. Incidentally, no correlation was found between widened PDL spaces or severe occlusal attrition and the presence of cervical loss of tooth structure, which casts doubt on the currently popular concept of abfraction.

Adult↗

Periodontal disease in pregnancy complicated by type 1 diabetes mellitus.

BACKGROUND: Systemic disease and hormonal changes have been implicated as complicating factors for periodontal disease. Diabetes has been identified as a risk factor for periodontal disease, and diabetics can experience periodontal destruction at an earlier age than non-diabetic individuals. Increased hormone levels during pregnancy can contribute to increased gingival inflammation. The purpose of this study was to examine the association of type 1 diabetes mellitus (DM) on the periodontal status of pregnant women. METHODS: Thirty-three (13 diabetic and 20 non-diabetic) subjects, 20 to 39 weeks gestation, participated in this study. The mean age of the diabetics and non-diabetics was 28.5 +/- 7.1 (SD) and 27.0 +/- 7.3 years, respectively. The following parameters were assessed at Ramfjord's reference teeth: plaque index (PI), gingival inflammation (GI), probing depth (PD), gingival margin (GM) location, and clinical attachment level (CAL). RESULTS: Diabetic subjects had significantly (P<0.001) higher PI (1.48 +/- 0.69) and GI (1.77 +/- 0.44) scores than non-diabetics (PI = 0.63 +/- 0.38; GI = 0.93 +/- 0.48). Mean PD for diabetics (2.95 +/- 0.69 mm) was significantly different (P<0.024) from that of non-diabetics (2.44 +/- 0.32 mm). Although mean GM location was coronal to the cemento-enamel junction (CEJ) in both groups, gingival margins were at a more apical position (P<0.001) in the diabetics (-0.20 +/- 1.24 mm) compared to non-diabetics (-1.76 +/- 0.53 mm). Mean CAL values also varied significantly (P<0.001) between diabetics (2.60 +/- 1.54 mm) and non-diabetics (0.68 +/- 0.65 mm). Significant differences were seen for GI (P<0.001), PD (P=0.005), GM location (P<0.001), and CAL (P<0.001) when assessing the effect of diabetes and controlling for plaque. When assessing the effect of plaque and controlling for diabetes, the only significant difference was GI (P=0.001). CONCLUSIONS: The results of this study demonstrate that periodontal inflammation and destruction are increased in pregnant diabetics as compared to non-diabetic pregnant patients. These findings may have implications for diabetic control and, hence, maternal and fetal outcomes in pregnant diabetic patients.

Adult↗

Clinical and radiological improvement of periodontal disease in patients with type 2 diabetes mellitus treated with alendronate: a randomized, placebo-controlled trial.

BACKGROUND: Alendronate (ALN) is an aminobisphosphonate commonly used for osteoporosis in postmenopausal women. We studied the effect of ALN on bone loss prevention in type 2 diabetes mellitus patients with periodontal disease. METHODS: In a controlled double-blind, randomized study we evaluated prospectively diabetic patients paired by gender and years since diagnosis for 6 months. The study included 40 patients (20 men and 20 women), 50 to 60 years old, with more than 5 years since diagnosis of diabetes and established periodontitis. They were randomly allocated to alendronate (10 mg/daily) or placebo treatment for 6 months. The endpoints of treatment were: the distance between the alveolar bone border and the cemento-enamel-junction (CEJ) evaluated by means of digital radiographic imaging, a biochemical marker of bone resorption (urine N-telopeptide) (Ntx), and periodontal parameters. Metabolic control was assessed at baseline and after 6 months. RESULTS: Baseline and 6-month glycated hemoglobin levels were similar in both groups. Alendronate induced a significant decrease in NTx at 6 months (P = 0.006). Periodontal parameters improved in both groups. However, they were significantly better for the ALN treated group. Alveolar bone border-CEJ distance increased in the placebo, but decreased in the ALN group (P = 0.0003). CONCLUSIONS: In type-2 diabetic patients, alendronate induced more improvement in alveolar bone crest height than control therapy. No differences in urinary N-telopeptide or glycated hemoglobin were observed in this short-term randomized controlled pilot trial.

Alendronate↗

Combined periodontal regenerative technique in human intrabony defects by collagen membranes and anorganic bovine bone. A controlled clinical study.

BACKGROUND: Combined periodontal regenerative technique (CPRT) is a surgical procedure that combines the use of barrier membranes with a filling material in the treatment of periodontal defects. The effectiveness of CPRT has been evaluated in many studies in comparison to GTR with membranes alone, but conflicting results have been obtained by different clinicians, particularly in the treatment of intrabony defects. The aim of the present study was to compare CPRT to GTR with collagen membranes in the treatment of human intrabony defects characterized by a relevant 1-wall component. METHODS: Thirty-four (34) healthy, non-smoking patients affected by moderate to severe chronic periodontitis participated in this study. Each patient had good oral hygiene and at least 1 radiographically detectable intrabony defect > or = 4 mm, with a 1-wall component of at least 50% of the defect, involving 2 tooth surfaces or more with a probing depth (PD) > or = 6 mm. Seventeen (17) subjects were randomly assigned to the test group and underwent CPRT by anorganic bovine bone and a collagen membrane, and 17 randomly assigned to the control group who received GTR with a collagen membrane alone. Pre- and post-therapy clinical parameters (probing depth [PD]; clinical attachment level [CAL]; gingival recession [GR]) and intrasurgical parameters (depth of intraosseous component [IOC]; level of the alveolar crest [ACL]) were compared between test and control groups 1 year after treatment. Vertical bone gain (VBG) from the base of the defect to the cemento-enamel junction was also evaluated in both groups. RESULTS: At the 1-year examination, clinical and intrasurgical parameters showed statistically significant changes within each experimental group from baseline. A statistically greater CAL gain was reported in the test group (P<0.05), whereas the control group exhibited more GR and alveolar crest resorption at a statistically significant level (P<0.01). VBG was significantly greater (P<0.01) at test sites (5.23 +/- 1.30 mm) compared to controls (3.82 +/- 1.28 mm). CONCLUSIONS: The results suggest that the use of CPRT may be preferred when bioabsorbable membranes are used to treat intrabony defects characterized by unfavorable architecture.

Absorbable Implants↗

Comparison of clinical, radiographic, and histometric measurements following treatment with guided tissue regeneration or enamel matrix proteins in human periodontal defects.

BACKGROUND: The purpose of this study was to compare the clinical and radiographic parameters with the histometric findings following 2 different regenerative procedures in humans. METHODS: Fourteen advanced intrabony defects at teeth scheduled for extraction were randomly treated as follows: 8 with guided tissue regeneration (GTR) using bioabsorbable barriers and 6 with an enamel matrix protein derivative (EMD). Standardized radiographs, probing depths (PD), and attachment levels (CAL) at baseline and 6 months after therapy were evaluated and compared to the histometric measurements made following the removal of teeth and surrounding tissues 6 months after the surgery. RESULTS: Significant PD reductions (GTR: -5.62 mm; EMD: -5.00 mm) and CAL gains (GTR: 3.87 mm; EMD: 2.67 mm) were observed in both groups. Six months after surgery, minor resorptions of the alveolar crest (AC) (GTR: 0.40 mm; EMD: 0.33 mm) and bony gain at the bottom of the defects (GTR: 0.47 mm; EMD: 1.05 mm) were observed radiographically. No statistically significant differences in the change of clinical and radiographic parameters between the GTR and EMD groups were found. Histometrically, significant amounts of new connective tissue attachment (i.e., cementum with inserting collagen fibers) were observed in both groups (GTR: 2.29 mm; EMD: 1.81 mm). Bone regeneration was found to be significant only in the GTR group (GTR: 1.93 mm; EMD: 0.78 mm). However, the study lacked statistical power for determining equivalence between the groups. CONCLUSIONS: Within the limitations of the present study, it may be concluded that at 6 months after GTR or enamel matrix protein derivative therapy, formation of new cementum and bone may be histometrically demonstrated. Except for the formation of new bone, no statistically significant differences between both therapies could be seen for clinical, radiographic, and histometric results 6 months after surgery.

Absorbable Implants↗

A clinical comparison of a bovine-derived xenograft used alone and in combination with enamel matrix derivative for the treatment of periodontal osseous defects in humans.

BACKGROUND: Enamel matrix protein derivative (EMD) and particulate anorganic cancellous bovine-derived bone xenograft (BDX) have both shown favorable clinical results in reducing intrabony periodontal defects as compared to open flap debridement alone. These materials have shown results comparable to those obtained with guided tissue regeneration. The primary aim of the present study was to evaluate the effectiveness of EMD combined with BDX as compared to BDX alone, with a secondary aim to compare the treatment outcomes of the 2 modalities. METHODS: Seventeen patients with paired intrabony defects and probing depths measuring > or = 5 mm who were being treated for chronic periodontitis were selected for this controlled, blinded, split-mouth study. Following non-surgical periodontal therapy, sites were randomly selected to receive either a combination of EMD and BDX (test group) or BDX alone (positive control group). Baseline and 6-month surgical reentry measurements were taken by a calibrated examiner blinded to the treatment. A paired Student t test was utilized to evaluate differences between baseline and post-treatment and between the treatment groups. RESULTS: Favorable clinical outcomes for both hard and soft tissue measurements were achieved for both treatment groups when compared to baseline (P < 0.001). There was no statistically significant difference for any of the measured clinical parameters. Probing depth reduction for the test group and control group was 4.2 +/- 1.1 mm and 3.9 +/- 1.3 mm, respectively (P > 0.8). Mean gain in clinical attachment levels for the test and control groups was 3.8 +/- 0.9 mm and 3.7 +/- 1.5 mm, respectively (P > 0.6). Hard tissue measurements obtained at surgical reentry were used to calculate the bone fill (BF) and percent bone fill (%BF). The BF was 3.2 +/- 1.4 mm and 3.0 +/- 1.2 mm (P > 0.6), and the %BF was 63.3 +/- 16.3% and 67.0 +/- 19.0% (P > 0.4) for the EMD + BDX and BDX groups, respectively. CONCLUSIONS: In summary, both the particulate anorganic cancellous bovine-derived bone xenograft used alone and in combination with enamel matrix derivative are effective for the treatment of human intrabony periodontal lesions.

Adult↗

Long-term results of guided tissue regeneration therapy with non-resorbable and bioabsorbable barriers. II. A case series of infrabony defects.

BACKGROUND: The aim of this 5-year follow-up case series was to clinically and radiographically evaluate the long-term results after guided tissue regeneration (GTR) therapy of infrabony defects using non-resorbable and bioabsorbable barriers. METHODS: In 12 patients with advanced chronic periodontitis 12 pairs of contralateral infrabony defects were treated. Within each patient one defect received a non-resorbable (expanded polytetrafluoroethylene [ePTFE]; control: C) and the other a bioabsorbable (polyglactin 910; test: T) barrier by random assignment. At baseline and at 6 and 60 +/- 3 months after surgery clinical parameters and standardized radiographs were obtained. Gain of bone density within infrabony defects was assessed using subtraction radiography. RESULTS: Eight of 12 patients were available for the 60-month reexaminations. Six and 60 +/- 3 months after GTR therapy statistically significant (P < 0.05) vertical attachment (CAL-V) gain was observed in both groups (C6:2.6 +/- 1.4 mm; C60: 1.6 +/- 1.5 mm; T6:3.0+/- 1.7 mm; T60: 3.0 +/- 0.7mm). However at 60 months, 2 infrabony defects in the control group had lost all the attachment that had been gained 6 months after therapy and a clinically relevant but statistically in significant mean CAL-V loss of 1.0 +/- 2.1 mm was observed from 6 to 60 months. The case series failed to show statistically significant differences between test and control regarding CAL-V gain 60 months after surgery. Also subtraction analysis failed to reveal statistically significant differences regarding density gain between both groups 6 and 60 months postsurgically (C6: 26.4 +/- 54.2; C60 62.8 +/- 112.7; T6: 68.7 +/- 72.8; T60. 84.1 +/- 83.6). CONCLUSIONS: CAL-V gain achieved after GTR therapy in infrabony defects using both non-resorbable and bioabsorbable barriers was quite stable after 5 years in 14 of 16 defects.

Absorbable Implants↗

A histopathologic investigation on the effects of electrical stimulation on periodontal tissue regeneration in experimental bony defects in dogs.

BACKGROUND: One endpoint of periodontal therapy is to regenerate the structure lost due to periodontal disease. In the periodontium, gingival epithelium is regenerated by oral epithelium. Underlying connective tissue, periodontal ligament, bone, and cementum are derived from connective tissue. Primitive connective tissue cells may develop into osteoblasts and cementoblasts, which form bone and cementum. Several procedural advances may support these regenerations; however, the regeneration of alveolar bone does not always occur. Therefore, bone stimulating factors are a main topic for periodontal reconstructive research. The present study was designed to examine histopathologically whether the application of an electrical field could demonstrate enhanced alveolar and cementum regeneration and modify tissue factors. METHODS: Seven beagle dogs were used for this experiment. Mandibular left and right sides served as control and experimental sides, respectively, and 4-walled intrabony defects were created bilaterally between the third and fourth premolars. The experimental side was treated with a capacitively coupled electrical field (CCEF) (sinusoidal wave, 60 kHz, and 5 V peak-to-peak), applied for 14 hours per day. The following measurements were performed on the microphotographs: 1) the distance from the cemento-enamel junction to the apical notch (CEJ-AN) and from the crest of newly formed bone (alveolar ridge) to the apical notch (AR-AN); 2) the thickness of new cementum in the apical notch region; and 3) the length of junctional epithelium. The following histopathologic parameters were assessed by a semiquantitative subjective method: 1) inflammatory cell infiltration (ICI); 2) cellular activity of the periodontal ligament; 3) number and morphology of osteoclasts; 4) resorption lacunae; and 5) osteoblastic activity. RESULTS: The results showed that the quantity of new bone fill and the mean value of the thickness of the cementum were significantly higher for the experimental side (P < 0.01). The location of the base of the pocket was positioned more coronally with respect to the apical point of the coronal notch in the experimental side (statistically significant P < 0.01). The length of the junctional epithelium and the number of osteoclasts were higher in the stimulated side than the coronal side; these findings were also statistically significant (P < 0.01). The comparison of the electrically stimulated versus non-stimulated mandibles with the semiquantitative subjective method demonstrated statistically significant differences in defined histopathologic parameters, except for osteoclast morphologies (P > 0.05). CONCLUSIONS: This study demonstrated that the CCEF method has the potential to produce reconstructive effects and bone deposits. Further investigations with respect to the theoretical determination of local field parameters of the periodontal tissue complex, such as permittivity, conductivity, strength of the field electrical stimulation applied to the periodontal field current density, wavelength, and signal frequency appropriate for this field, should be undertaken. Using different electromotive forces alone or in combination with bone graft materials, guided tissue regeneration techniques, and dental implants may achieve a new dimension in periodontal therapy in the near future.

Alveolar Bone Loss↗

A scanning electron microscopy study of idiopathic external tooth resorption in the cat.

BACKGROUND: Multiple idiopathic root resorption (MIRR) is a rare condition in man characterized by cervical resorption leading to significant tooth loss. A similar condition, feline osteoclastic resorptive lesions (FORL), affects up to 70% of domestic cats and thus provides a valuable model for investigating the etiopathogenesis of MIRR. The aim of the present study was to establish changes in the surface microanatomy of the tooth in late stage FORL and to identify whether its location has a surface bias. METHODS: Scanning electron microscopy (SEM) was used to analyze the surface features of enamel and cementum of feline teeth affected with advanced FORL. RESULTS: Resorption involved the coronal root at the cementoenamel junction (CEJ) in 95% of teeth and focal resorption of intact enamel was observed in 14% of teeth. In 55% of teeth, the main lesion was on the buccal surface and a distinct circumferential resorption "front" was present at the apical margin of resorption. The root surfaces of most affected teeth either lacked extrinsic fibers or cellular lacunae or featured evidence of cementum remodeling. Woven bone-like tissue was found within lesions, on resorbed dentin, or on the root surface in 27% of teeth. CONCLUSIONS: This study demonstrates that most FORL involve the CEJ, and the presence of focal lesions at this site suggests that this is where resorption is initiated. This implies that local factors in the oral microenvironment play a role in the etiopathogenesis of this condition. The study also shows that FORL are more likely to occur on buccal surfaces and are associated with changes in the microarchitecture of the root surface consistent with destruction of the normal periodontal attachment and stimulation of a reparative response. These findings may be relevant to understanding the etiopathogenesis of multiple idiopathic resorption areas in man.

Animals↗

Clinical and anatomical factors limiting treatment outcomes of gingival recession: a new method to predetermine the line of root coverage.

Complete root coverage is not always achievable, even in gingival recession with no loss of interproximal attachment and bone. The cemento-enamel junction is the most widely used referring parameter to evaluate root coverage results. The aim of the present study was to describe the most frequent diagnostic mistakes that may lead to incomplete root coverage in Miller Class I and II gingival recessions and to suggest a method to predetermine the level/line of root coverage in non-molar teeth. The line of root coverage (i.e., the level/line to which the soft tissue margin will be positioned after the healing process of a root coverage surgical technique) was predetermined by calculating the ideal vertical dimension of the interdental papilla of the tooth with the recession defect. This method was applied to 120 recession-type defects affecting non-molar teeth of 80 young healthy subjects that were treated with root coverage surgical procedures over the last 5 years. All recessions were Miller Class I or II and were associated with at least one of the following characteristics: 1) traumatic loss of the tip of the interdental papilla(e); 2) tooth rotation; 3) tooth extrusion with or without occlusal abrasion; and 4) a cervical abrasion defect with no evidence of the cemento-enamel junction. The line of root coverage may be considered the clinical cemento-enamel junction because it may substitute the anatomic cemento-enamel junction when this is no longer clinically visible on the tooth with recession or when the ideal conditions to obtain complete root coverage are not fully represented.

Dental Occlusion, Traumatic↗

Alternative rubber dam isolation technique for the restoration of Class V cervical lesions.

This article describes an expedited, atraumatic technique of restoring cervical abrasion-erosion, abfraction or carious lesions using an alternative placement sequence of the dental rubber dam for adequate field isolation. As shown by this technique, the rubber dam retainer is modified and positioned on the tooth with subsequent placement of the dental dam material over theretainer and tooth. This technique saves time and provides good retraction of the gingival tissue and isolation of the cavity preparation from contamination (saliva, hemorrhage) that can potentially cause post-operative symptoms and possible restoration replacement.

Dental Caries↗

Cervical microleakage in MOD restorations: in vitro comparison of indirect and direct composite.

This study compared microleakage between indirect composite inlays and direct composite restorations. Forty-eight standard inlay MOD cavities, with cervical margins located either in enamel or dentin, were prepared in extracted human third molars. The specimens were randomly divided into 3 groups (n=16). In the control group, the cavities were restored with the composite Filtek Z250 (3M ESPE). For the experimental groups, indirect restorations were made with the Artglass (Heraeus-Kulzer) or Belleglass HP (Kerr Laboratories) systems and cemented with the dual curing cement RelyX ARC (3M ESPE). The adhesive system Single Bond (3M ESPE) was applied on all groups. The specimens were submitted to thermolcycling, coated with nail varnish, then immersed in 2% basic fuchsine aqueous solution for 24 hours. The teeth were then sectioned and leakage scores were evaluated (40x), based on a standard ranking. Data were submitted to statistical analysis (Mann-Whitney and Kruskal-Wallis tests) with a 95% confidence level. No statistical difference was found between substrates (p=0.595), and the materials performed similarly in dentin (p=0.482). Direct restorations showed higher leakage than indirect restorations at the enamel margins (p=0.004). Within the limitations of this experimental design, overall leakage was similar between both substrates, while the indirect systems provided a better sealing than direct composites only in enamel.

Composite Resins↗

Microleakage in the proximal walls of direct and indirect posterior resin slot restorations.

This study compared the degree of microleakage in the proximal walls of direct and indirect resin slot restorations in relation to the types of dentin bonding systems and the location of gingival margins. Two Class II slot preparations were prepared and restored in each of 60 extracted human molars using direct (Filtek Supreme) and indirect (Tescera ATL) restorative resin materials. Various types of dentin bonding systems, including self-etching (OneStep Plus/Tyrian SPE, iBond, Xeno III) and etch and rinse systems (All-Bond 2, Prime & Bond NT) were used to restore the prepared teeth. The gingival proximal wall was placed apical to the cementoenamel junction (CEJ) in 1 proximal box and coronal to the CEJ in the other. The specimens were stained and evaluated for microleakage using a digital imaging and analysis system. Significant differences were found in the degree of microleakage observed in the various restorative groups. In general, the group restored with indirect resin had less microleakage than the direct resin groups. Factors, such as type of dentin bonding system and location of gingival margins, exert a substantial influence on the degree of microleakage that occurred along the walls of proximal resin restorations.

Acid Etching, Dental↗

Microleakage after thermocycling of 4 etch and rinse and 3 self-etch adhesives with and without a flowable composite lining.

This study evaluated the microleakage of composite fillings prepared with 4 etch and rinse and 3 self-etch adhesive systems after thermocycling. Also evaluated was the potential improvement of cavity sealing when utilizing a low charged resin lining for cavity preparations. Seventy recently extracted teeth were randomly allocated to 7 experimental adhesive systems: two 3-step etch and rinse adhesive systems, Scotchbond Multipurpose (SBMP) and Optibond Solo Plus (OS); two 2-step etch and rinse adhesive systems, referred to as "one-bottle," Scotchbond 1 (SB1) and Gluma Comfort Bond + Desensitizer (G); and 3 self-etch "all-in-one" adhesives, Adper Prompt-L-Pop (PLP), Xeno III (X-III) and iBond (iB). On each tooth, 2 rectangular cavities were prepared at the cemento-enamel junction: 1 cavity was prepared with adhesive and the hybrid composite and the second was filled with the same adhesive and a thin layer of flowable composite (Filtek Flow) under the resin composite (Z100). All teeth were thermocycled for 800 cycles (5 degrees C-55 degrees C, 30 seconds dwell time). Leakage was evaluated on a 6-point (0-5) severity scale for enamel and dentin on 4 interfaces for each restoration. The results are expressed as means +/- standard deviation (SD). Microleakage scores were analyzed by means of generalized linear mixed models (GLMM), assuming an ordinal logistic link function. Covariates in the model were: (1) adhesives, (2) fluid composite and (3) interface. The model also accounts for repeated measurements on the various teeth. The authors found that the mean score of microleakage per tooth was significantly higher at the enamel rather than at the dentin interfaces (1.21 +/- 0.51 and 0.87 +/- 0.48; p<0.0001). In this study, there was no significant difference among the 4 etch and rinse adhesive systems. On the other hand, these adhesives yielded smaller mean scores of microleakage than the 3 self-etch systems (respectively, 0.85 +/- 0.2 and 1.3 +/- 0.5; p<0.0001). Among the self-etch adhesives, microleakage was significantly greater for PLP (1.74 +/- 0.46) than for the other self-etch products (p<0.0001), while X-III, an intermediary strong self-etch, was found to be as good as the etch and rinse systems, with a mean score of 0.97 +/- 0.27. In addition, results have also shown that an under layer of flowable composite significantly improved the water tightness of the PLP adhesive restorations (p=0.042). This in vitro study concluded that the self-etch adhesives remain less effective than etch and rinse. Nevertheless, X-III, a self-etch adhesive, showed acceptable performance in accordance with this study's 6-point severity scale of microleakage, but this needs to be confirmed in further clinical studies. On the other hand, this study failed to reveal that the addition of a thin layer of fluid composite improved the water tightness of the restoration, except for PLP.

Acid Etching, Dental↗

Quantitative assessment of vertical heights of maxillary and mandibular bones in panoramic radiographs of elderly dentate and edentulous subjects.

The clinical applicability of vertical measurements of the mandible and maxilla in panoramic radiographs was studied by assessing the variety of vertical heights among 91 elderly dentate subjects. Measurements in each jaw and calculations of a maxillary ratio were made at five sites. Variations in measurements of the dentate subjects were small: 9-11% for vertical measurements in the mandible, 6-11% for vertical measurements in the maxilla, and 8-10% for the maxillary ratios. These findings suggest that it is possible quantitatively to assess heights of the mandibular and maxillary bones in panoramic radiographs. Reductions in the edentulous jaws were assessed by comparing the heights of jaws of elderly dentate subjects with those measured in 177 elderly edentulous subjects. Significant differences in heights of the mandibular body and maxilla were found between the dentate and the edentulous (P < 0.001). Edentulous women had greater values for percentage reduction in the mandibles than did the men (P < 0.01; P < 0.001 in various locations).

Aged↗