Changes in salivary output after induction at high-altitude areas and its effects on dental caries among Indian Army troops.

BACKGROUND: This study was aimed to evaluate the changes in salivary output and its effect on dental caries among Indian troops after 6 months of stay at high-altitude area (HAA). METHODS: All troops undergo mandatory dental checkup during acclimatization phase before deployment at HAA. Two thousand troops who fulfilled inclusion and exclusion criteria were selected, and consent for the study was obtained. Stimulated and unstimulated salivary samples were collected, the decayed, missing, and filled teeth (DMFT) index was evaluated, and required dental treatment was completed. The same salivary samples were collected after 6 months (on deinduction) to evaluate the salivary output. The DMFT index was re-evaluated to check the initiation of caries. RESULTS: The mean values of unstimulated and stimulated saliva at the initial visit were 4.105 and 17.03 gm, respectively, whereas the mean values of unstimulated and stimulated saliva after 180 days were 3.034 and 15.831 gm, respectively. Salivary flow was found to be significantly decreased after 6 months both in unstimulated and stimulated saliva. The mean DMFT at the time of induction of the study was 6.18 ± 3.03, and on deinduction, it was 7.22 ± 3.45 with p < 0.001, which was highly statistically significant. CONCLUSION: A decrease in body fluids and changed sympathetic and parasympathetic at HAA lead to decreased salivary secretions. Low water intake, high carbohydrate solid diet, negligible supply of fresh food, difficulty in maintenance of oral hygiene, and overall stress due to loneliness are all contributory factors for an increase in dental caries. It clearly demonstrates that prolonged stay at HAA affects salivary volume outflow, both stimulated and unstimulated, which has a corresponding effect on new caries.

Intrapulpal thermal changes during direct provisionalization using various autopolymerizing resins: Ex-vivo study.

BACKGROUND: Resin materials used in the fabrication of direct provisional restoration exhibit an exothermic reaction and the extent of damage may also depend on the remaining dentine thickness. An ex-vivo study was envisaged to compare the time related temperature changes in the pulp chamber during the fabrication of fixed partial denture provisional restorations using direct technique. The effect of differently prepared teeth (with varying remaining dentine thickness) on the above mentioned temperature changes were also evaluated. METHODS: Thermal changes were calculated in pulp chamber of three differently prepared tooth having different amount of remaining dentinal thickness (45 samples) and control with no tooth media (15 samples), using three different types of autopolymerizing provisional restorative materials using Cr/Al thermocouple connected to digital thermometer. RESULTS: The data for the mean peak temperature rise was subjected to one way ANOVA analysis for relative comparison among subgroups within each main group and across the main groups. The results showed a statistically significant difference across both the subgroups and the main groups (p < 0.001). Then Turkey HSD test was applied to determine the significance of statistical difference between the means, within the groups. The differences in temperature rise were statistically significant for the three resins (p < 0.001). CONCLUSION: Polymethylmethacrylate (DPI) showed the highest temperature rise value followed by polyethyl methacrylate (Tempron) and Bis-acrylate composite (CoolTemp). The maximum temperature rise was found on molar full veneer preparation followed by molar three quarter preparation and premolar three quarter preparation. Data and results from current study may assist clinicians to select an autopolymerizing provisional restorative resin when employing direct technique of fabricating provisional restorations for a specific tooth preparation which would cause minimal thermal trauma to pulpal tissue.

Dimensional accuracy of two rubber base impression materials as a function of spacer design and techniques in custom trays for fixed partial dentures.

BACKGROUND: A prostheses can't be better than the cast over which it has been fabricated. To make accurate casts, accurate impressions are mandatory. To get an accurate and dimensionally stable impression, various techniques and materials have been advocated. This study compares the most commonly used techniques and materials for dimensional accuracy. Two types of spacers were designed to compare the addition silicon and polyether and their techniques. METHODS: A metal die was used to make the impressions. A total of 60 impressions were made using multiple mix and monophasic techniques for addition silicon and polyether in custom trays. A travelling microscope was used to measure the dimensional accuracy of die stone casts retrieved from impressions. RESULTS: The results were compared using paired t test and SPSS software. The study was highly significant (p < 0.001). The polyether was more accurate than the addition silicon and spacer design I (adapted to the edentulous area) was more accurate than the design II (spacer over the abutments, not adapted to edentulous area). The multiple mix technique was more accurate than the monophasic for addition silicon. CONCLUSION: The combination of multiple mix technique with spacer design I for addition silicon gave the best accurate results.

A clinico radiographic study of immediate loading implants in rehabilitation of mandibular ridges.

BACKGROUND: Numerous studies regarding the immediate loading of splinted implants retaining/supporting mandibular dentures have reported promising results, but studies comparing splinted and unsplinted attachments for supporting overdentures with immediate loading are limited. Scientific literature is sparse comparing various attachment systems and patient satisfaction in response to immediately loaded implant supported overdentures. METHODS: A total of 30 completely edentulous patients male or female, in the age group of 54-78 years (mean age 65 years), wearing conventional complete dentures were selected and randomly divided in to two groups. A total of 60 implants were placed in the interforaminal area of the mental symphysis (two implants per patients) in 30 patients. Two types of attachment systems namely Ball for group-A and Bar for group-B were used and immediate loading done. Implants were evaluated clinically and radiographically at baseline, 1 month, 3 months, 6 months and 9 months. All clinical and radiographic parameters were subjected to statistical analysis. RESULT: The implant survival rate for group-A (ball attachment) was 93.3% and implant survival rate for group-B (bar attachment) was 93.3%. The overall implant survival rate was not dependent on the attachment system. There was no significant difference in the crestal bone loss in mesial, and distal side in implants with respect to ball and bar attachment for different period of observation (F = 0.25; P = 0.910; F = 0.07; P = 0.992 respectively). CONCLUSION: Overdenture supported by two implants should be the minimum gold standard in the rehabilitation of completely edentulous patients.

Evaluation of flexural strength of resin interim restorations impregnated with various types of silane treated and untreated glass fibres.

BACKGROUND: Flexural strength is an important mechanical property that determines the long-term prognosis of interim restorations. Studies are lacking regarding the effect of silanation of the various types of glass fibre impregnation on the flexural strength of resin interim restorations. METHODS: A customized metal die was milled to simulate the prepared abutments of a three-unit fixed dental prosthesis. A total of seventy five samples of interim fixed dental prostheses were prepared using autopolymerizing tooth colour acrylic resin. Unidirectional and woven forms of glass fibres (Stick and Stick Net), which were silane treated and untreated were used to reinforce the resin matrix. Fifteen samples were prepared for each group along with unreinforced group serving as control. The flexural strength was evaluated with universal testing machine. RESULTS: The means and standard deviations of flexural strength for different groups were 13.90 ± 2.96 (control), 61.58 ± 5.26 (unidirectional fibres), 30.89 ± 3.60 (woven fibres), 112.05 ± 5.51 (silane treated unidirectional fibres) and 73.85 ± 4.10 (silane treated woven fibres) respectively. The mean flexural strength of silane treated unidirectional fibres (112.05 MPa) was highest and statistically highly significant (P < 0.0001) compared to all other groups. CONCLUSIONS: Within the limitations of the current study, flexural strength of the reinforced PMMA interim fixed dental prosthesis was significantly higher (P < 0.0001) when compared to the unreinforced PMMA interim fixed dental prosthesis. The use of silane treated unidirectional glass fibres is an effective method of reinforcing interim fixed restorations made of PMMA resins.

Clinical evaluation of immediate implants using different types of bone augmentation materials.

BACKGROUND: The immediate placement of implants into fresh extraction socket has proven to be a safe and predictable procedure. However, there is lack of scientific evidence regarding the healing pattern and osseointegration associated with immediate implants especially with different grafting materials. METHODS: A total of 30 patients male or female, with a mean age of 23.1 years ± 6.0 in the age group of 18-38 years, each having at least one tooth indicated for extraction (either maxillary or mandibular anterior teeth) were selected and randomly divided in to two groups. 30 Implants (Xive(®) friadent, Germany) were placed into fresh extraction sockets during this study. Two types of graft materials namely Dembone(®) (freeze-dried bone allograft) for group A and G-Bone(®) (modified hydroxyapatite) for group B were used. After implant placement all implants were evaluated clinically and radiographically at baseline, 3 months, 6 months, 9 months and 12 months. All clinical and radiographic parameters were subjected to statistical analysis. Intragroup comparisons were made with paired 't' test and intergroup comparisons with unpaired 't' test (P > 0.05 NS, ≤0.05 S, ≤0.01 HS). RESULT: During the 1-year interval, no implant was lost and the mean bone level at the implants was maintained or even improved. CONCLUSION: Immediate restoration of single tooth implants placed in fresh extraction sockets could be considered a valuable option to replace a missing tooth. The graft materials used in both groups have been found to be equally effective.

Prediction of sustained virological response to combination therapy with pegylated interferon alfa and ribavirin in patients with genotype 3 chronic hepatitis C.

BACKGROUND: Sustained virological response (SVR) rates in patients with hepatitis C are heterogeneous and are influenced by a wide range of host and viral factors. AIM: To evaluate the efficacy of combination therapy with pegylated interferon alfa (PEG-IFN-α) and ribavirin (RBV), and document the SVR rates taking into consideration various predictive factors in patients with chronic hepatitis C (CHC) genotype 3. METHODS: Ninety-seven treatment-naive patients with CHC genotype 3 (mean age 41.46±11.51 years, M:F ratio 79:18), who received a combination of PEG-IFN (α-2a or α-2b) and RBV were retrospectively analyzed (2006-2008) for the early virological response (EVR) at 12 weeks, end of treatment response (ETR), and SVR at 6 months. RESULTS: Eighty-four (86.6%) patients achieved EVR and 81 (83.5%) achieved ETR, while SVR was achieved in 65 (67.0%) patients. Of the 84 patients who achieved EVR, 77 (91.7%) achieved ETR and 61 (72.6%) achieved SVR at 6 months. Age and body mass index (BMI) were found to be important predictors (*P<0.05) of SVR. CHC patients with a history of alcohol intake showed decreased SVR (52%) (*P=0.035) as compared to nonalcoholics (80%). Cirrhotic versus noncirrhotic patients showed no difference in SVR (54.5% vs. 70.7%) (P=0.157). Serum alanine aminotransferase (ALT) (P=0.169) and hepatitis C virus (HCV) RNA levels (P=0.42) also did not have an influence on the SVR. CONCLUSION: Combination therapy with PEG-IFN-α and RBV demonstrated good tolerability in CHC genotype 3 infection. Age, BMI, and alcohol consumption play an important role in determining treatment outcome.

Midline Fractures in Single Maxillary Complete Acrylic vs Flexible Dentures.

BACKGROUND: Patients using single maxillary denture against their natural mandibular teeth face the problem of midline fracture in their routine acrylic dentures. Various techniques have failed over the years to address the problem. In this study, flexible denture material (Lucitone) with injection moulding system has been used and evaluated for midline fracture in these patients. METHODS: A total of 58 patients in the age group of 38 to 80 years, who had experienced midline fracture in their acrylic maxillary dentures were selected. They were provided with new dentures using flexible denture material. Various parameters, namely, mastication, phonetics, esthetics and comfort level were evaluated. RESULT: Only two cases reported slight crack in the palatal region of the-maxillary dentures after 18 months of use. Mastication and phonetics were found to be improved with flexible dentures. CONCLUSION: The flexible denture is a promising material for preventing midline fractures in a single maxillary denture. It is well tolerated by the patients as compared to the methyl meth-acrylate dentures.

Secondary and Delayed Bone Grafting in Alveolar and Anterior Palatal Clefts.

BACKGROUND: Surgical repair with suitable bone graft / substitutes plays an important role in rehabilitation of individuals with residual anterior palatal or alveolar defects associated with an oronasal fistula. METHODS: 52 cases were treated by secondary or delayed bone grafting of the alveolar defects in isolation or associated with defects of the anterior palate from July 2002 - Nov 2004. Dimension and the extent of the defects were assessed with the help of radiographs & maxillofacial CT. Cephalometric analysis, presurgical orthodontics and dentofacial orthopedics preceded surgical repair with cancellous graft from the iliac crest, followed by post surgical orthodontics and prosthetic rehabilitation. RESULT: Satisfactory results were achieved in 49 cases with three cases showing failure of graft acceptance. Postoperative clinical and radiological evaluation for all the patients was done at an interval of one, three and six months. Bone density and trabeculation was comparable to the adjacent bone within six months. CONCLUSION: Recreating the bony continuity of the maxillary arch followed by orthodontic correction of dental discrepancies achieves a comprehensive orthosurgical correction.

Flexible denture base material: A viable alternative to conventional acrylic denture base material.

Although clinician's skills and experience play a major role in designing and fabrication of the optimum prosthodontic restorations, the selection of denture resins is equally important, especially when the patient has been using the prostheses since long. Eighteen cases who were not satisfied with their conventional acrylic dentures were selected. They were provided flexible dentures along with a questionnaire to precisely evaluate the advantages of new material. Prosthodontic planning & observations regarding this material are discussed on various parameters.

Portal hemodynamics after large-volume paracentesis in patients with liver cirrhosis and tense ascites.

Large-volume paracentesis with a plasma expander has been extensively evaluated and shown to be an effective and safe therapy. While hepatic and systemic hemodynamics have been studied extensively, there is little information on portal hemodynamics by duplex Doppler. Portal vein diameter, portal flow velocity, and portal blood flow were measured with duplex Doppler in 11 cirrhotic patients before and 24 hr after large volume paracentesis. There were no significant changes in the portal vein diameter (9.88+/-2.62 mm vs 10.09+/-2.73 mm), portal flow velocity (10.65+/-2.60 vs 10.01+/-2.58 cm/sec), and portal blood flow (488+/-288.9 vs 502+/-73.38 ml/min), before and 24 hr after large-volume paracentesis. Thus, significant changes in portal hemodynamics do not occur after large-volume paracentesis.