Sialo-odontogenic cyst--a case report.

Sialo-odontogenic cyst is an uncommon cyst of odontogenic origin that occurs in the tooth bearing areas of the jaws. These lesions are histopathologically unique, biologically aggressive and may sometimes warrant distinction from central muco-epidermoid carcinoma and botryoid variant of the lateral odontogenic cyst. Sialo-odontogenic cysts tend to recur and various factors are quoted for their recurrence viz., the presence of microcysts, thin connective tissue wall, etc. We are herewith reporting a case of sialo-odontogenic cyst for its relative rarity among the odontogenic cysts.     

Differences in mouse strain influence leukocyte and immunoglobulin phenotype response to Porphyromonas gingivalis

This study examined the nature of the infiltrating cells in Porphyromonas gingivalis-induced lesions and immunoglobulins in the serum samples of BALB/c (H-2^d), C57BL6 (H-2^b), DBA/2J (H-2^d) and CBA/CaH (H-2^k) mice. Mice were immunized intraperitoneally with P. gingivalis outer membrane antigens or sham-immunized with phosphate-buffered saline followed by subcutaneous challenge with live organisms 1 week after the final immunization. The resulting skin abscesses were excised 7 days later, cryostat sections cut and an immunoperoxidase method used to detect the presence of CD4⁺ and CD8⁺ T-cell subsets, CD14⁺ macrophages and CD19⁺ B cells. Peroxidase positive neutrophils and IgG1- and IgG2a-producing plasma cells were also identified. Anti P. gingivalis IgG1 and IgG2a subclass antibodies were determined in serum obtained by cardiac puncture. Very few CD8⁺ T cells and CD19⁺ B cells were found in any of the lesions. The percentages of CD4⁺ cells, CD14⁺ cells and neutrophils were similar in lesions of immunized BALB/c and C57BL6 mice, with a trend towards a higher percentage of CD14⁺ cells in sham-immunized mice. The percentage of CD14⁺ cells was higher than that of CD4⁺ cells in immunized compared with sham-immunized DBA/2J mice. The percentages of CD4⁺ and CD14⁺ cells predominated in immunized CBA/CaH mice and CD4⁺ cells in sham-immunized CBA/CaH mice. The percentage of neutrophils in immunized CBA/CaH mice was significantly lower than that of CD14⁺ cells and CD4⁺ cells in sham-immunized mice. IgG1⁺ plasma cells were more dominant than IgG2a⁺ cells in immunized BALB/c, C57BL6 and DBA/2J mice, whereas IgG2a⁺ plasma cells were more obvious in sham-immunized mice. IgG2a⁺ plasma cells were predominant in immunized and sham-immunized CBA/CaH mice. In the serum, specific anti-P. gingivalis IgG2a antibody levels (Th1 response) were higher than IgG1 levels (Th2 response) in sham-immunized CBA/CaH and DBA/2J mice. In immunized BALB/c mice, IgG2a levels were lower than IgG1 levels, while IgG2a levels were higher in immunized C57BL6 mice. In conclusion, this study has shown differences in the proportion of infiltrating leukocytes and in the subclasses of immunoglobulin produced locally and systemically in response to P. gingivalis in different strains of mice, suggesting a degree of genetic control over the response to P. gingivalis.     

Effect of ProRoot MTA mixed with chlorhexidine on apoptosis and cell cycle of fibroblasts and macrophages in vitro

AIM: To compare the percentage of apoptotic cells and the cell cycle profile of fibroblasts and macrophages exposed to either ProRoot mineral trioxide aggregate (MTA) mixed with chlorhexidine (CHX), or exposed to ProRoot MTA mixed with sterile water. METHODOLOGY: Mouse gingival fibroblasts or mouse macrophages were seeded in six-well plates and allowed to attach overnight. Freshly mixed or set (allowed to dry for 24 h) specimens of tooth-coloured (white) ProRoot MTA were prepared with 0.12% CHX gluconate (MTA/CHX) or with sterile water (MTA/H2O). The cells were exposed for 24 h to the MTA specimens, which were placed over permeable membrane inserts to avoid direct contact with the cells. Untreated cells served as controls. Propidium iodide staining followed by flow cytometry was used to evaluate the effects of ProRoot MTA on cell apoptosis and cell cycle. Statistical analyses were performed by one-way anova followed by post-hoc tests with the use of the SigmaStat 2.0 software, and significance was determined at P < or = 0.05. RESULTS: MTA specimens containing CHX induced apoptosis of macrophages and fibroblasts (P < 0.05). In contrast, no change in the proportion of apoptotic cells was observed when sterile water was used to prepare the specimens (P > 0.05). Cell cycle analysis showed that exposure to MTA/CHX decreased the percentage of fibroblasts and macrophages in S phase (DNA synthesis) as compared with exposure to MTA/H2O (P < 0.05). CONCLUSION: This in vitro study demonstrated that the substitution of CHX for sterile water in MTA increases its cytotoxicity. This suggests that the potentially beneficial antimicrobial effect of CHX may be accompanied by an increase in the cytotoxicity of the resulting MTA-based material.     

Tissue destruction in periodontitis: bacteria or cytokines fault?

The pathogenesis of periodontal disease involves the sequential activation of a great variety of components of the host immune response, primarily acting to defend periodontal tissues against bacterial aggression, but also functioning as mediators of tissue destruction. The expression of the disease results from the interaction of host, microbiological agents, and environmental factors. Leukocytes play a critical role in the pathogenesis of the disease, producing different cytokines, chemokines, and other mediators, thus generating a host defense response, as well as inducing tissue inflammation and bone destruction. The aim of this review is to address the role of some inflammatory mediators in response to bacterial aggression in periodontitis.     

Do traditional techniques produce better conventional complete dentures than simplified techniques?

OBJECTIVES: To compare the quality of conventional complete dentures fabricated with two different techniques. A randomized controlled clinical trial was conducted to compare traditional (T) and simplified (S) methods of making complete conventional dentures on patients' ratings of satisfaction, comfort and function at 3 and 6 months following delivery. The quality of the prostheses was rated by prosthodontists at 6 months. MATERIALS AND METHODS: One hundred twenty-two male and female edentulous individuals, aged 45-75 years, were randomly allocated into groups that received dentures made with either T or S methods. Following delivery, patients' ratings of several denture-related factors were measured using 100mm visual analogue scales, and denture quality was assessed by blinded prosthodontists using ratings on a validated quantitative scale. RESULTS: There were no significant differences between the two groups in patient ratings for overall satisfaction (3 months: mean T = 83 mm, mean S = 83 mm, P = 0.97; 6 months: mean T = 79 mm, mean S = 79 mm, P = 0.96) or in prosthodontists' ratings of denture quality (T = 66, S = 63; P = 0.38). CONCLUSION: These results show that the quality of complete dentures does not suffer when manufacturing techniques are simplified to save time and materials. Dental educators should consider these findings when re-designing prosthodontic training programs.     

Evaluation of endodontic treatments performed by students in a Brazilian Dental School

The aims of this study were to evaluate the clinical outcomes of root canal treatments performed by final-year students in the Dental School of Piracicaba, State University of Campinas, SP, Brazil, during the year 2000 and to evaluate the success rate of these treatments at follow-ups conducted one and three years later (2001-03). All 579 endodontic treatments performed by final-year students were selected for this investigation. Detailed personal and dental history was obtained from the patient's records. Clinical and radiographic follow-up examinations were performed. For 78.8 percent of the cases, dental caries was recorded as the cause for performing endodontic treatment; for 8.8 percent, prosthetic reasons were given; and for 12.4 percent, failure of the endodontic treatment was the reason. The largest percentage (30.7 percent) of recalled patients was examined after one year; the success rate at this follow-up evaluation ranged from 83 percent to 96 percent depending on the pulp status prior to the root canal treatment. After three years, only 8 percent of treated patients returned; assessment for them revealed a 75.5 percent success rate. Dental caries is still the main reason for endodontic treatment. This level of success of the root canal treatment in a Brazilian dental school is similar to other reports in the literature.     

Groove associated periodontitis: classification proposal and clinical. Case report

The presence of a palatoradicular groove (PRG), more frequently observed at the level of the upper lateral incisors, may compromise both the radicular pulp and the periodontium leading to endodontic-periodontal lesions. Frequently, the prognosis of these elements is compromised because of the missed diagnosis or because of the complex therapeutic approach that is necessary to cure the associated pathologies. A histopathological and clinical classification is proposed showing according to the degree of the affected tooth involvement. Preventive measures are also discussed and a clinical case is reported. A 49-year-old woman presented with a PRG at the superior left lateral incisor, endodontically treated years before, associated with probing pocket depths of 10 mm and 7 mm, clinical attachment loss of 11 mm and first degree mobility. The tooth was treated with splinting, periodontal surgery with radiculoplasty, root surface conditioning, guided tissue regeneration and with a prosthetic crown for esthetic rehabilitation. Six years later, the operated site showed probing pocket depths of 3 mm, gains in clinical attachment level of 4 mm and 7 mm and reduction of tooth mobility. The ceramic crown re-established an acceptable esthetics for the patient. Even in the presence of a 3(rd) degree PRG, according to the classification presented, the prognosis of the tooth may be positive through the association of root canal treatment, periodontal and prosthetic therapy. The classification presented shows the clinician the best therapeutic approach.     

Impedance of metastable pitting corrosion

A metastable pitting corrosion impedance investigation has been performed. The shape of the dc current is connected with the shape of the impedance diagram. The corrosion rate inside an active pit is charge transfer controlled. The active surface area expansion is proportional to the double layer capacity changes. Changes of the electrolyte resistance inside the pit have been detected.     

Marginal adaptation of mineral trioxide aggregate (MTA) compared with amalgam as a root-end filling material: a low-vacuum (LV) versus high-vacuum (HV) SEM study

AIM: To compare the marginal adaptation of mineral trioxide aggregate (MTA) or amalgam root-end fillings in extracted teeth under low-vacuum (LV) versus high-vacuum (HV) scanning electron microscope (SEM) viewing conditions. METHODOLOGY: Root-end fillings were placed in 20 extracted single-rooted maxillary teeth. Ten root ends were filled with MTA and the other 10 root ends were filled with amalgam. Two 1 mm thick transverse sections of each root-end filling were cut 0.50 mm (top) and 1.50 mm (bottom) from the apex. Gap size was recorded at eight fixed points along the dentine-filling material interface on each section when uncoated wet (LV wet (LVW)) and dry under LV (0.3 Torr) in a JEOL JSM-5800 SEM and backscatter emission (LV dry uncoated (LVDU)). The sections were then air-dried, gold-coated and gap size was recorded once again at the fixed points under HV (10(-6) Torr; HV dry coated (HVDC)). Specimen cracking, and the size and extent of the crack were noted. RESULTS: Gap sizes at fixed points were smallest under LVW and largest under HVDC SEM conditions. Gaps were smallest in MTA root-end fillings. A General Linear Models Analysis, with gap size as the dependent variable, showed significant effects for extent of crack in dentine, material and viewing condition (P = 0.0001). CONCLUSIONS: This study showed that MTA produced a superior marginal adaptation to amalgam, and that LVW conditions showed the lowest gap size. Gap size was influenced by the method of SEM viewing. If only HV SEM viewing conditions are used for MTA and amalgam root-end fillings, a correction factor of 3.5 and 2.2, respectively, may be used to enable relative comparisons of gap size to LVW conditions.