Journal of Dental Materials and Techniques
Volume:3 Issue: 4, Autumn 2014

A resilient soft liner (RSL) has been used in processed complete dentures but controlling its thickness has always been a challenge because of uneven reduction of the denture’s intaglio surface. Use of a thermoplastic vacuum-formed template and an endodontic K-file, as guides, for the reduction of a processed mandibular complete denture to receive RSL is described in the present report. A processed mandibular complete denture is prepared by reducing its borders and drilling holes in its surface. A thermoplastic sheet adapted to the intaglio surface and an endodontic K-file with rubber stop adjusted to the desired dimension are used as guides to the reduction procedure and allows intermittent measuring of the reduced areas. This technique helps in reducing the processed denture’s intaglio surface in a controlled manner thus maintaining the strength of the denture base and effectiveness of soft liner. It also makes the application of resilient soft liner a cost and time effective maneuver

The purpose of this study was to investigate the effect of flask investment materials on the color changes of different brands of resin denture teeth. Resin denture teeth (560) were divided into 2 groups according to the materials used for flask investment (silicone or gypsum). All the specimens were thermocycled between 4°C and 60°C with 60-s dwell times for 1,000 cycles. Subsequently, the specimens of each group were divided into 4 subgroups based on the immersion media: coffee, tea, cola, and distilled water. Digital images of the teeth were taken before immersion and 30 days after immersion. The color samples were measured using the CIE L*a*b* system, and color differences (∆E) were calculated. The data were evaluated by three ways ANOVA and the Tukey HSD test. There was not a significant difference in ∆E using three-way ANOVA, while the results showed considerable statistical differences with two factor ANOVA interaction. The ∆E values in the silicone group were significantly more than those in the gypsum group (P<0.001). Among the solutions in which specimens were kept, maximum discoloration was seen with coffee followed by cola, tea, and distilled water. The Ivoclar Vivadent denture teeth in the silicone group, as well as the Apple teeth in the gypsum group exhibited the highest level of color stability. All test groups exhibited visually perceptible color changes; the denture teeth and flask investment materials, as well as the nutritional habits, significantly affected the color stability of the resin denture teeth.

Temporomandibular joint disorders (TMD) are the most common disorders of the jaw, and despite their clinical importance, they are not completely understood. This study was aimed to evaluate the changes of temporomandibular joint (TMJ) on cone beam computed tomography (CBCT) images in disc displacement vs. osteoarthritis of the TMJ. In this study, 45 patients, including 37 women and 8 men (13-89 years of age), were examined. The patients were selected based on RDC/TMD criteria and group I disorders were excluded from the study. Accordingly, group II consisted of 43 joints with jaw clicking or displaced discs, and group III comprised 46 joints with crepitus. CBCT images in sagittal, coronal, and axial sections were examined to assess osseous changes in terms of flattening, sclerosis, erosion, resorption, and osteophyte formation. Data were analyzed using statistical tests including the chi-square, Mann-Whitney, and Kolmogorov-Smirnov tests with the confidence interval of 95%. Mann-Whitney test for the comparison of mean age between groups II and III was not statistically significant (p value=0.06). A significant differences was found between two (RDC/TMD) groups according to the prevalence of condylar erosion, resorption, and osteophyte (p<0.05). Similar findings were present between articular eminence flattening, erosion, resorption and (RDC/TMD) groups (P-value<0.05). The pattern of bony changes was different in osteoarthritis when compared with in disc displacement. Most of the changes were concentrated in various parts of the condyle and the articular eminence with no particular changes in the mandibular fossa

Although composite resins have improved greatly since their introduction, microleakage is one of the most frequently encountered problems. This study compared the effects of different monomer systems and layering techniques on the bacterial leakage of Cl I composite resin restorations. Eighty-two sound human third molars were used. The teeth were randomly divided into six groups of 12 teeth each and two positive and negative control groups of five teeth. Class I cavities, measuring 4×4×2 mm, were prepared. The first three groups were filled with a silorane-based composite (Filtek P90) using three different methods of filling (bulk, incremental and snowplow) and the remaining three groups were filled with a methacrylate-based composite (Clearfil AP-X) using the same techniques. The specimens were stored for 24 hours at 37°C and then thermocycled up to 1000 cycles. The bacterial leakage of the specimens was assessed in a microbiological laboratory and statistical analyses of data were performed by Fisher’s exact and chi-squared tests (P<0.05). There were no significant differences between Filtek P90 and Clearfil AP-X (P=1) in terms of microleakage. The difference between the outputs related to three filling techniques was not significant, either (P>0.05). Leakage occurred similarly in both silorane- and methacrylate-based composite resins and three filling techniques.

Beta calcium sulfate hemihydrate (BCSH), which is commonly known as “Gypsum plaster” has long been used as bone graft material because of its excellent biocompatibility and the ability for bone regeneration. Several methods have been used for the preparation of BCSH, including heat treatment of calcium sulfate dihydrate with water, application of inorganic acids or condensed inorganic salt solutions under high or atmospheric pressure. As a bone graft, it is preferred that the BCSH powder has a granular form for the purpose of manipulation, bio-mechanical properties and ease of injection. For this study granules of BCSH in the size of 500 to 700 micrometers were manufactured and sterilized using gamma ray. For assessing the regeneration of thismaterial, six rabbits were selected and granules were injected in the bone defects that were made using diamond bur in their skull under general anesthesia. Biopsies for histological evaluations were done 3, 6, 9, 12, 14 and 16 months following surgery. At the third month time-point, remodeling of the BCSH was evident, and complete newly formed bone was seen in the region of the defect. The results of this study demonstrated that BCSH had a good biocompatibility without inducing an inflammatory response and promoted bone healing.

Alveolar osteitis (AO) is one of the most common postoperative complications after third molar surgery. Various techniques have been used to reduce the risk of AO. The aim of the current study was to evaluate the effect of Chlorhexidine (CHX) bioadhesive gel in preventing the development of AO. Patients with bilateral impacted mandibular third molars underwent surgical extraction of both teeth. One socket was randomly received CHX gel and the contralateral socket served as the control. The outcome variable was development of AO and the CHX gel application was the predictor variable. Data were analyzed using chi-square test with the confidence interval of 95%. 41 patients (27 females and 14 males) with mean age of 24.15 ± 5.02 years underwent 82 surgeries. Total of 11 sockets (13.41%) developed AO. The frequency of AO in CHX gel (2 cases, 4.87%) side was significantly lower than control (9 cases, 21.95%) side (P-value < 0.05). No side effects observed following CHX gel application. Application of CHX gel could be an effective approach to reduce the risk of developing AO following mandibular third molar surgery.

This study aims to evaluate the dentomaxillofacial radiographic changes in end stage renal disease (ESRD) patients who were on hemodialysis. Parathyroid hormone (PTH), calcium, phosphorus and alkaline phosphatase (ALP) measurements, as well as Panoramic and periapical radiographs were obtained from seventy four patients with a history of end stage renal disease (ESRD). 74 patients examined with age range of 15 to 68 years, and a mean age of 41.4±14.6 years. The duration of dialysis ranged between 3 to 156 months with a mean duration of 40.4 months. Thinning or loss of lamina dura was observed in 16 patients (51.4%) and calcification of the pulp in 28 patients (40%). Changes in trabecular pattern was observed in 30 patients (40.6%), alterations in jaw bone density in 29 patients (39.2%) and bilateral calcification of stylohyoid ligaments in 13 patients (17.6%). We did not notice any non periapical origin radiolucent lesion. There was a significant relationship between bone trabecular pattern with P level, age and duration of dialysis. Changes in bone density showed significant relationship with frequency and hours of dialysis per week. No correlation was found between the radiographic changes and Ca level. Although changes in trabecular pattern and density were observed mostly in those who were on hemodialysis for a relatively long time, but we could not establish a definitive relation of radiographic manifestations in ESRD patients with the duration and frequency of dialysis.

Direct restoration of severely damaged endodontically treated teeth (ETT) using available and conventional and current matrix systems is sometimes impractical and in some clinical cases is impossible. The aim of this paper is to introduce and describe a new matrix system based on Rigid Tray Technique (RTT) for dealing with such difficult clinical cases.