Sis Darendeliler Yaman

Analysis of stress distribution in a maxillary central incisor subjected to various post and core applications

In this study, stress distribution in a maxillary central incisor that was subjected to endodontic treatment and various post and core applications was determined by using a three-dimensional finite-element method. Cast gold post and gold core and different combinations of prefabricated stainless steel post, or a prefabricated titanium post with amalgam or composite cores were considered. In all cases, the tooth was assumed to have a porcelain crown. The primary purpose of the study was to evaluate the stress distribution due to simulated biting forces and thus investigate the reliability of different post and core applications. It was found that, within the limitations of the study, the cast gold post and gold core application yielded the best result. The second purpose of the study was to highlight the importance of using a unique stress value, which contains the effects of all the possible stress components existing upon loading in the determination of a possible failure. A resultant stress value and all the constituent components were shown in detail, and it was proved that an estimation independently based on an individual component might lead to erroneous results.

Analysis of stress distribution in a vertically condensed maxillary central incisor root canal

In this study, the stress distribution in a maxillary central incisor subjected to an endodontic treatment was determined by using a three-dimensional finite-element method. The tooth had a variable root canal cross-sectional area, and the canal was assumed to be filled with vertical condensation. The Clinical practice was simulated by considering the obturation in successive stages. The main aim of the study was to investigate the possibility of fracture due to the obturation process. It was found that, within the limits of the study, the likelihood of a root fracture in such a process is a remote possibility.

Sealing ability of retrofilling materials following various root-end cavity preparation techniques

The aim of this study is to compare the sealing efficacy of the retrograde cavity preparations prepared and filled with different equipment and materials. In the study, low speed burs, ultrasonic or Er, Cr:YSGG laser devices were used for cavity preparations and ProRoot MTA and MTA-Angelus as filling materials. Seventy-eight single-rooted teeth were instrumented, root filled, and grouped. Root-end cavities were prepared and filled by using the following: Group 1: Low-speed carbide bur + ProRoot MTA; Group 2: Low-speed bur + MTA-Angelus; Group 3: Ultrasonic retrotips + ProRoot MTA; Group 4: Ultrasonic retrotips + MTA-Angelus; Group 5: Er, Cr:YSGG laser tips + ProRoot MTA; Group 6: Er, Cr:YSGG laser tips + MTA-Angelus. Microleakage was measured using a fluid filtration technique. Differences in the fluid movement among groups were analyzed with a two-way analysis of variance (ANOVA) and LSD test. The results showed a significant difference between the groups prepared with laser and carbide bur (p < 0.05). No difference was found between root-end filling materials (p > 0.05). According to the results of the study, the cavities prepared with Er, Cr:YSGG laser demonstrated significantly lower microleakage in all the filling materials considered.

Sealing ability of lateral compaction and tapered single cone gutta-percha techniques in root canals prepared with stainless steel and rotary nickel titanium instruments

Objectives: The aim of this study was to evaluate the sealing ability of lateral compaction and tapered single cone gutta-percha techniques in root canals prepared with stainless steel and rotary nickel titanium root canal instruments by fluid filtration method. Study design: The root canals were prepared with stainless steel (SS) and nickel titanium (NiTi) instruments. The canals prepared with SS were obturated with lateral compaction technique using .02 tapered cones and the canals prepared with NiTi instruments were obturated with lateral compaction technique using .02 tapered cones or 06 tapered single cones. The amount of leakage was evaluated by fluid filtration model. The results were statistically analyzed with one-way ANOVA. Results: The group prepared with NiTi instruments and filled with lateral compaction technique showed significantly less coronal leakage than the group prepared with SS instruments and filled with lateral compaction technique (p<0.05). There was no statistically difference between apical leakages of groups (p>0.05). Conclusions: Obturation with lateral compaction of gutta-percha provides a superior coronal seal whilst canal instrumentation with engine-driven NiTi files reduces the extent of microleakage in root canals when compared with stainless steel hand instruments. Tapered single cone technique was comparable with lateral compaction technique because of easier application. Key words:Apical leakage, coronal leakage, lateral compaction technique, single cone technique.

Temporomandibular joint findings in patients with rheumatoid arthritis, ankylosing spondylitis, and primary Sjögren's syndrome

AIM The aim of the present study was to investigate the prevalence of temporomandibular joint (TMJ) symptoms in rheumatoid arthritis (RA), primary Sjögrens syndrome (pSS), and ankylosing spondylitis (AS) patients. METHODS The present study consisted of 79 individuals with various rheumatic disease (study group: 39 with RA, 17 with AS, 23 with pSS) and 79 age- and sex-matched healthy controls (control group). Subjective symptoms of the TMJ were recorded by means of a questionnaire. And stomatognathic examination was then performed. RESULTS The prevalence of subjective symptoms in patients with rheumatic disease (73.4%) were significantly higher than that of the controls (22.8%; P<.05). The most common objective symptoms were pain during lateral TMJ palpation (29.1% of patients overall, 8.9% of controls) and mandibular movements (19% of patients overall, 2.5% of controls), and muscle pain during palpation (38% of patients overall, 3.8% of controls). They were significantly higher in all of the rheumatic patients than the controls (P<.05). There was not a statistically-significant difference in the values for mandibular movements between the study and control groups (P>.05, Mann-Whitney U test). CONCLUSIONS TMJ symptoms were observed to be higher in the patients with RA, AS and pSS than the control group. Dentists and rheumatologists should be aware of TMJ symptoms in patients with rheumatic diseases.

Analgesic Efficacy of Prophylactic Gabapentin and Lornoxicam in Preventing Postendodontic Pain

OBJECTIVE In dental applications, as in all other medical applications, pain needs to be prevented or at least controlled. The use of the tooth as a model for studying pain mechanisms is well established. In the current study, we aimed to evaluate and compare the analgesic effects of gabapentin and lornoxicam, respectively, vs a placebo for postendodontic treatment pain. DESIGN AND METHODS Clinical research was planned as prospective, randomized, and placebo controlled. Each subject was given 600 mg gabapentin (group G: N = 30), 8 mg lornoxicam (group L: N = 30), or a placebo (group C: N = 30) 30 min prior to endodontic treatment. OUTCOME MEASURES At 4 (T(3)), 8 (T(4)), 12 (T(5)), and 24 (T(6)) h after preoperative (T(0)) time points, the analgesic efficacies of the agents were evaluated by using the visual analog scale (VAS). RESULTS In group G, VAS values were significantly greater at T(0) time point than at T(5) or T(6). T(0) time point VAS value in group L was lower than at T4 time point and greater than at T(6). In group C, T(0) time point VAS values were significantly lower at T(3) and T(5) time points and greater than at T(6) time point. VAS values in group G at T(5) time point were significantly lower than in group C or group L (P < 0.05). CONCLUSIONS Based on the obtained data, prophylactic lornoxicam controlled postendodontic treatment pain more effectively than did the placebo drugs, and gabapentin was more effective in controlling the pain than either lornoxicam or the placebo.