The correlation between neovascularization and bone formation in the condyle during forward mandibular positioning

The aim of the present study was to investigate the temporal pattern of expression of VEGF (Vascular Endothelial Growth Factor) and new bone formation in the condyle during forward mandibular positioning. The importance of vascularization during endochondral ossification was investigated during natural growth of the condyle and compared to that after forward mandibular positioning. The goal was to further our understanding of the cellular responses during functional appliance therapy with a view to extending the experiment into maturity. One hundred and fifty 35 days old Sprague-Dawley rats, 100 fitted with a bite-jumping appliance and 50 untreated, were divided into 10 groups. One group was sacrificed on each of experimental days 3, 7, 14, 21, 30, 33, 37, 44, 51 and 60 respectively. Sagittal sections were cut and stained with VEGF antibodies and Periodic acid and Schiff's reagent (PAS). Each section was quantitatively analyzed with a computer assisted analyzing program and the temporal sequence of expression of VEGF and new bone formation during natural growth and after mandibular forward positioning was compared. There was significant increase in both vascularization and mandibular bone growth upon forward mandibular positioning and the highest amount of both were expressed in the posterior region of the condyle. The highest acceleration of vascularization preceded that of new bone formation. Thus, forward mandibular positioning was found to solicit a sequence of cellular events leading to increased vascularization and subsequently new bone formation resulting in enhanced condylar growth.     

Beurteilung der Angiogenese und Osteogenese unter dem Einfluss von Vascular endothelial growth factor (VEGF)

Purpose. This intention of this study was to investigate the influence of controlled release of vascular endothelial growth factor (VEGF) on angiogenesis and osteogenesis in a mandibular defect model. Methods. A total of 56 rabbits were operated and bicortical holes were placed in the mandible. The defects were filled with collagen type I implants, collagen implants complexed with 0.8-µg VEGF₁₆₅, or left without any filling. After 3, 7, 14, and 28 days specimens were taken and histologic, histomorphometric, and immunohistologic analyses were carried out concerning density of vessels, total surface of vessels, bone surface, and bone density. Results. The number of vessels was increased in all groups up to 14 days, followed by physiologic regression in the control groups, whereas the study group showed persistently high numbers. The density of regenerated bone was significantly higher in the study group. Conclusion. The activation of angiogenesis using VEGF₁₆₅ leads to more intensive angiogenesis and bone regeneration.     

Compositional analysis of human acquired enamel pellicle by mass spectrometry

Relatively little is known about the formation of the acquired enamel pellicle other than that it involves the selective adsorption of specific proteins from oral fluids. Previous studies on the identification of pellicle components have relied largely on immunological or enzymatic detection and have been hampered by the fact that only minute quantities of pellicle can be removed from tooth surfaces. The present work describes an improved method of harvesting pellicle that combines mechanical and chemical removal; this approach was used to investigate systematically the desorption of in vitro pellicle components with different solutions. Eleven major in vitro pellicle proteins were identified by using a combination of electrophoretic separation and matrix-assisted laser desorption/ionization-reflectron time-of-flight mass spectrometry. A similar analysis of in vivo-formed pellicle revealed the presence of intact statherin, lysozyme, albumin and amylase. Further analysis of in vivo pellicle by liquid chromatography-electrospray ionization mass spectrometry suggested the presence of numerous low molecular-weight fragments of precursor proteins. The protein composition of in vitro whole-salivary pellicle adsorbed to hydroxyapatite and that of in vivo enamel pellicle differed for proline, the result of a reduction in the content of acidic proline-rich proteins in the in vivo samples. Unique features of the oral environment such as enzymatic activities or mineral surface properties may account for these differences between in vivo and in vitro pellicle formation.     

Intra-familial transmission and distribution of Prevotella intermedia and Prevotella nigrescens

The periodontal bacteria Prevotella intermedia and Prevotella nigrescens have been recently separated from each other. The purpose of this study was to investigate the distribution and routes of transmission of these bacteria among family members. Seven patients with moderate to severe periodontitis were selected. These probands, their spouses and 14 of their children were investigated. The presence of Pr. Intermedia and Pr. nigrescens was determined by culture techniques in pooled subgingival plaque samples, in the saliva, on the tongue, tonsils and buccal mucosa. Differentiation of Pr. intermedia and Pr. nigrescens was performed by enzyme electrophoretic mobility. From all 7 patients, as well as 4 spouses and 3 of the children, Pr. intermedia could be isolated. Pr. Nigrescens was found in 2 of the 7 patients, in 5 of the spouses and in 5 of the 6 children aged 5–10 yr. In the 8 children aged 0–4 yr both species were seldom isolated. These data are in accordance with earlier findings that Pr. Intermedia is associated with periodontitis and Pr. Nigrescens with a relatively healthy periodontal condition. Ribotyping of bacteria was performed by hybridization of Hindlll restriction endonuclease digests of chromosomal DNA with ribosomal DNA. Isolates from unrelated individuals always had distinct ribotypes. Indistinguishable ribotypes of Pr. intermedia and Pr. Nigrescens were found both among married couples and among parents and children. This indicates that intrafamilial transmission of Pr. intermedia and Pr. Nigrescens is possible both between adults and between parents and children.     

The incidence and structure of inflammatory diseases of the maxillofacial area based on data from the Surgical Department of Pediatric Dentistry of the 2d Clinic of the Tashkent Medical Institute

Reviews the results of studies of the incidence and structure of inflammatory diseases of the maxillofacial area over 5 years. Defines the major principles of medical rehabilitation of children suffering from inflammatory diseases. Validates the usefulness of special wards for purulent conditions at a department for pediatric oral surgery.     

Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis

This study investigated the role of infection on the prognosis of endodontic therapy by following-up teeth that had had their canals cleaned and obturated during a single appointment. The root canals of 55 single-rooted teeth with apical periodontitis were thoroughly instrumented and irrigated with sodium hypochlorite solution. Using advanced anaerobic bacteriological techniques, post-instrumentation samples were taken and the teeth were then root-filled during the same appointment. All teeth were initially infected; after instrumentation low numbers of bacteria were detected in 22 of 55 root canals. Periapical healing was followed-up for 5 years. Complete periapical healing occurred in 94% of cases that yielded a negative culture. Where the samples were positive prior to root filling, the success rate of treatment was just 68%— a statistically significant difference. Further investigation of three failures revealed the presence of Actinomyces species in each case; no other specific bacteria were implicated in failure cases. These findings emphasize the importance of completely eliminating bacteria from the root canal system before obturation. This objective cannot be reliably achieved in a one-visit treatment because it is not possible to eradicate all infection from the root canal without the support of an inter-appointment antimicrobial dressing.     

Java project on periodontal diseases: the relationship between vitamin C and the severity of periodontitis

OBJECTIVE: To study the relationship between vitamin C and the severity of periodontitis. MATERIAL AND METHODS: The study population consisted of subjects from the Malabar/Purbasari tea estate on West Java, Indonesia. In 2002, clinical measurements were performed in 128 subjects, including evaluation of plaque, bleeding on probing, pocket depth and attachment loss. In 2005, 123 out of 128 subjects could be retrieved who were present at the examination of 2002. Blood samples were taken to measure plasma vitamin C levels. Information about the subject's dietary habit was obtained by means of a personal interview guided by a questionnaire. RESULTS: Plasma levels of vitamin C ranged from 0.02 to 34.45 mg/l with a mean of 7.90 mg/l (+/-5.35). The correlation coefficient between plasma vitamin C level and periodontal attachment loss was -0.199 (p<0.05); stepwise linear regression revealed that vitamin C levels explained 3.9% of the variance in periodontal attachment loss. Subjects with vitamin C deficiency (14.7% of the study population) had more attachment loss compared with those with depletion or normal plasma vitamin C values. CONCLUSION: The negative association between plasma vitamin C levels and periodontal attachment loss suggests that vitamin C deficiency may contribute to the severity of periodontal breakdown.     

Short-term fluoride release from various aesthetic restorative materials

The short-term fluoride release of a giomer (Reactmer), a compomer (Dyract AP), a conventional glass ionomer cement (Fuji II Cap) and a resin-modified glass ionomer cement (Fuji II LC) was evaluated and compared. Specimen discs (6 +/-0.2 mm diameter and 1 +/- 0.2 mm thick) were prepared for each material using custom molds. Each disc was placed in 1 ml of deionized for 24 hours at 37 degrees C. After one day, the water was extracted and analyzed. The specimen discs were then re-immersed into another 1 ml of fresh deionized water. The procedure of removing and refilling the water was repeated for 28 days. Sample solutions taken during the first seven days and at days 14, 21 and 28 were introduced into a capillary electrophoresis system using field amplified sample injection (FASI) to determine fluoride release. Data was analyzed using factorial ANOVA/Scheffe's post-hoc test at significance level 0.05. An initial fluoride "burst" effect was observed with glass ionomers. Both compomer and giomer did not show an initial fluoride "burst" effect. With the exception of the compomer, fluoride release at day one was generally significantly greater than at the other time intervals. The glass ionomers released significantly more fluoride than the compomer and giomer at day one. Although fluoride release of the giomer was significantly greater than the other materials at day seven, it became significantly lower at day 28.     

Expression of endothelial adhesion molecules in the alveolar ridge mucosa,gingiva and periimplant mucosa

OBJECTIVES: The purpose of this study was to analyze the expression of adhesion molecules on endothelial cells in the alveolar ridge mucosa, the gingiva and the periimplant mucosa in humans. MATERIAL AND METHODS: Twelve partially edentulous subjects were included in the study. In each subject, one soft tissue biopsy was harvested from the edentulous alveolar ridge mucosa, one from a tooth site and one from an implant site. After 3 weeks of undisturbed plaque accumulation, an additional biopsy was obtained from one tooth and one implant site in each subject. The tissue samples were snap frozen and prepared for immunohistochemical analysis. RESULTS: In the alveolar ridge mucosa, smaller proportions of endothelial cells expressing ICAM-1, ELAM-1 and VCAM-1 were observed than in the gingiva. ELAM-1-positive cells occurred in lower numbers than in periimplant mucosa. After 21 days of plaque accumulation, ELAM-1 was increased in tooth sites, but decreased in periimplant mucosa. CONCLUSION: The results of the present study indicated that the proportions of activated endothelial cells and the extravasation of leukocytes is larger in gingiva and periimplant mucosa than in alveolar ridge mucosa. This might be due to the less permeable keratinized epithelial layer in the edentulous ridge mucosa, which offers proper protection against microbial pathogens. The greater expression of endothelial cell adhesion molecules during experimental gingivitis, compared to periimplant mucositis, may reflect its longer history of repeated antigenic assaults.