Distribution of plasma-membrane Ca2+ pump in mandibular condyles from growing and adult rabbits

Chondrocytes may control the mineralization of the extracellular matrix of condylar cartilage by several mechanisms including the release of microvesicles involved in the initial nucleation, the creation or modification of the local matrix to help propagate or restrict mineralization, and the regulation of the ionic environment at the calcifying foci within the matrix. The plasma membrane Ca2+-Mg2+ ATPase (Ca2+ pump) is known to play a part in the vectorial efflux of calcium in a variety of cells including chondrocytes. The purpose here was to study the distribution of Ca2+-pump protein in mandibular condyles from growing and adult rabbits, and compare the expression of that protein in progressively differentiating chondrocytes whose final stage is associated with a mineralized extracellular matrix. Ca2+-pump antigen was identified immunohistochemically in six growing and six adult rabbit mandibular condyles with a Ca2+ pump-specific monoclonal antibody. The presence of Ca2+-pump antigen was established in hypertrophic chondrocytes, and in osteoblasts and osteoclasts of subchondral bone. Slot-blot analysis of nitrocellulose-immobilized chondrocyte homogenates showed that the amount of Ca2+ pump in growing cartilage was more than twice that in adult cartilage (p < 0.05). The demonstration of Ca2+-pump antigen in the hypertrophic chondrocytes of growing rabbit condyles is consistent with a role for the plasma-membrane Ca2+ pump in the calcification of mandibular condylar cartilage.     

Management of interdental papillae loss with forced eruption, immediate implantation, and root-form pontic

BACKGROUND: A 25-year-old Asian woman complained of an unesthetic black triangle between her upper right front teeth. Defective interdental papillae may result from external root resorption, which makes esthetic restoration more difficult. A combined use of forced eruption, immediate implant placement, and a root-form pontic made a successful esthetic and functional restoration. METHODS: The treatment sequences of this patient included short-term forced eruption, subsequent immediate implant placement after tooth extraction, and a provisional root-form pontic restoration. A final prosthesis was completed 6 months later, followed by clinical maintenance. RESULTS: Papillae were augmented by forced eruption. After immediate implantation and root-form pontic placement had been performed, the peri-implant soft and hard tissues were manipulated and maintained in a stable state. CONCLUSIONS: We successfully reconstructed the interdental papillae and replaced the deficient tooth with an immediate implantation. During 2 years of follow-up, the implant and peri-implant structures remained stable and healthy.     

产黑色素普氏菌DNA探针的制备及鉴定

本研究旨在应用DNA探针杂交技术快速检测产黑色素普氏菌、利用产黑色素普氏菌经酚抽取全染色体DNA，并以缺口转移法标记32P，制备探针。结果证实，该探针能够检测到膜上2×104的纯菌；当产黑色素普氏菌和中间普氏菌以不同比例混合点膜时，该探针能够检测到占混合菌群17％的目的菌；与口腔感染常见菌株杂交，未见交叉反应。     

Thickness of posterior palatal masticatory mucosa: the use of computerized tomography

BACKGROUND: Periodontal plastic surgery is used to fulfill the esthetic and functional demands of patients. The palatal masticatory mucosa is the main donor site for connective tissue, and the thickness of the graft tissue obtained is an important factor for the success of this technique. The aim of this study was to measure the thickness of masticatory mucosa in the posterior palatal area using computerized tomography (CT). METHODS: The thickness measurements were performed on the images of 100 adult subjects who underwent CT on the maxilla for implant surgery. Twenty-four standard measurement points were defined in the hard palate according to the gingival margin and the middle palatal suture. The radiographic measurements were used after calibration. The data were analyzed to determine the differences in the mucosal thickness according to gender, age, tooth position, and depth of the palatal vault. RESULTS: The overall mean thickness of the palatal masticatory mucosa was 3.83 +/- 0.58 mm (range: 2.29 to 6.25 mm). Females had significantly thinner mean masticatory mucosa (3.66 +/- 0.52 mm) than males (3.95 +/- 0.60 mm) (P <0.0001). The thickness of the palatal masticatory mucosa increased with age. The mean thickness according to tooth site was 3.46 mm (maxillary canine), 3.66 mm (first premolar), 3.81 mm (second premolar), 3.13 mm (first molar), 3.31 mm (the base of the interproximal papilla of the first and second molars), and 3.39 mm (second molar). There was an overall increase in the thickness of the palatal masticatory mucosa as the distance from the gingival margin to the middle palatine suture increased, with the exception of the Ca-d (a point at 12 mm from the gingival margin of the canine) region. There was no significant difference in the thickness of the palatal masticatory mucosa between the groups with high or low palatal vaults. CONCLUSIONS: The palatal masticatory mucosa thickness increased from the canine to premolar region but decreased at the first molar region and increased again in the second molar region, with the thinnest area at the first molar region and the thickest at the second premolar region. The canine to premolar region seems to be the most appropriate donor site that contains a uniformly thick mucosa. CT can be considered an alternative method for the measurement of palatal soft tissue thickness.     

Correlation between micro-computed tomography and histomorphometry for assessment of new bone formation in a calvarial experimental model

Conventional histologic or histomorphometric evaluation provides clear evidence of the bone healing process. However, the sample preparation process is tedious and destructive, and the three-dimensional (3D) anisotropic information of the bone trabeculae is compromised. Micro-computed tomography (microCT) has been introduced as an alternative to these traditional evaluation methods. microCT is noninvasive and provides a faster approach to evaluate and quantify cancellous bone. Most previous studies that used microCT have focused on studying trabecular structures of cancellous bone. In this study, we used microCT to analyze the micro-architecture of the regenerated membranous bone using a rabbit cranial defect model. Two 1 cm diameter circular bony defects were created in 12 New Zealand white rabbits. Specimens were harvested at 6 weeks and 12 weeks after surgery and were scanned using a MicroCT machine (Skyscan 1072, Aartselaar, Belgium). The specimens were then sectioned and stained with Goldner's trichrome. Bone volume density (BV/TV), bone surface density (BS/BV), and trabecular thickness (TbTh) were determined from histomorphometric and two-dimensional (2D) and 3D microCT analysis. Pearson's correlation coefficient (gamma), paired t-tests, and intraclass correlation coefficients from measurements between the 2D and 3D microCT and histomorphometry were calculated. There were very strong positive correlations of BV/TV between histomorphometric and 2D or 3D microCT measurements. Correlation between histomorphometric and 2D microCT measurements for BS/BV was moderate, whereas correlation between histomorphometric and 3D microCT measurements was weak. Weak correlations in TbTh among the three methods were found. In conclusion, the present study suggests that, in evaluating micro-architectures in regenerated bones, the correlation between measuring methods vary according to the features measured.     

Recognition and phagocytosis of multiple periodontopathogenic bacteria by anti-Porphyromonas gingivalis heat-shock protein 60 antisera

The present study has been performed to evaluate Porphyromonas gingivalis heat shock protein (HSP) 60 as a candidate vaccine to protect against multiple putative periodontopathic bacteria. Mouse anti-P. gingivalis HSP antisera demonstrated the elevated IgG antibody titers against the multiple bacteria tested and cross-reacted with heat-induced bacterial proteins of the target bacteria. The antisera also demonstrated a significantly higher opsonophagocytosis function against all the target bacteria than the control sera (P<0.01). We concluded that P. gingivalis HSP 60 could potentially be developed as a vaccine against multiple periodontopathic bacteria.     

Analysis of continuous-wave obturation using a single-cone and hybrid technique

This study analyzed the adaptation of gutta-percha to prepared root canal walls using two obturation techniques and determined the influence of the System-B plugger depth on filling adaptation. Fifty-six extracted human mandibular molars were instrumented using Profile NiTi rotary instruments, stratified based on curvature, then randomly distributed into two groups. Group 1 was obturated using the single-cone continuous-wave technique. Group 2 was obturated with a hybrid technique: lateral condensation followed by a continuous-wave down-pack. Based on System-B plugger penetration, teeth were divided into three subgroups: (a) < 3.5 mm, (b) 3.5 to 4.5 mm, and (c) > 4.5 mm. Roots were horizontally sectioned at 1 mm and 3 mm coronal to the apical foramen, stained, and photographed. Four evaluators scored the adaptation of gutta-percha to the prepared canal walls. In 100% (n = 56) of the samples, no statistically significant difference existed between the two obturation methods at 1-mm (x = 1.80, SD +/- 0.69) or 3-mm (x = 1.804, SD +/- 0.69) sections. Best results were obtained with a plugger depth 3.5 to 4.5 mm from the working length.     

Reposition of intruded permanent incisor by a combination of surgical and orthodontic approach: a case report

This report presents a case of a completely intrusive luxation of an immature permanent central incisor in a 7 years 9 months-old girl. Because there are severe intrusive trauma and cortical alveolar bone fracture, it was impossible to reposition with orthodontic or surgical method alone. The intruded tooth was repositioned to healthy alveolar bone level by using surgical extrusion and stabilization with sutures and periodontal pack. After healing of adjacent bone, the intruded maxillary central incisor erupted orthodontically by removable orthodontic appliance. It was moved from a high position to level of adjacent tooth in about 7 months. A radiograph was taken 6 months after ceasing forced eruption, which demonstrated minor root resorption, but the alveolar bone height had increased.     

The effects of Ledermix paste on discolouration of mature teeth

AIM: The aims of this study were to: (i) investigate the effects of Ledermix paste as an intracanal medicament on discolouration of mature teeth, (ii) examine whether the discolouring effects were related to the method of application, and (iii) examine the effects of sunlight upon discolouration of mature teeth. METHODOLOGY: The root canals of 45 mature extracted human teeth were prepared and filled with either Ledermix paste, calcium hydroxide [Ca(OH)2], or saline. In group 1, Ledermix paste was placed apical to the cemento-enamel junction (CEJ), whilst in groups 2 and 3 the paste filled the entire pulp chamber and root canals. In group 4, a Ca(OH)2 and methyl cellulose paste and, in group 5, saline (control) were allowed to fill the pulp chamber and the root canals. Group 3 teeth were kept in the dark and the other groups were exposed to indirect sunlight for 12 weeks. RESULTS: After 12 weeks, sunlight exposure had caused dark grey-brown staining of the teeth in the Ledermix groups, but this did not occur when the teeth were kept in the dark. More severe staining was noted when Ledermix paste filled the pulp chamber than when the paste was restricted to below the CEJ. CONCLUSIONS: It was concluded that Ledermix paste may cause discolouration of teeth. Such effects can be minimized if placement of the paste is restricted to below the gingival margin. Clinicians should ensure that Ledermix paste is not left on the walls of access cavities.     

Electromyographic activity of the masseter muscle after radiofrequency therapy in an animal model

Purpose

The purpose of this study was to examine changes in the electromyographic (EMG) activity of the masseter muscle after radiofrequency therapy (RF).

Methods

Twelve rabbits were used in this study: four in each group according to the number of RF applications. Preoperative EMG in the masseter muscle was used as the control. EMG was recorded at 1, 2, 3, and 4 weeks after RF in each rabbit. The recorded data were analyzed in terms of voltage and frequency, and changes in recorded variables were compared among the groups. The relative activity in peak voltage, root mean square of the action potential, area of voltage, and area of frequency were investigated.

Results

When compared to preoperative values, the variables at 3 or 4 weeks after RF application were significantly different in the single and quadruple therapy groups (P?<?0.05). There was no significant difference in the other groups (P?>?0.05). When the samples were regrouped as two groups like small number of application group (one or two point) and large number of application group (three or four points), the area of voltage and the area of frequency were significantly different between the groups at 4 weeks (P?<?0.05).

Conclusions

Masseter muscle activity after RF was significantly decreased compared to its preoperative state. The decreased activity was related to the number of applications and time elapsed after RF.