Comparison of vertical forces during root canal filling with three different obturation techniques.

The aim of this study was to examine and compare vertical forces exerted during root canal obturation with the cold lateral condensation technique, Thermafil technique and ProTaper guttapercha. Fourty-five single-rooted permanent teeth were used in the study. All specimens were instrumented using the ProTaper rotating technique and were randomly divided into three experimental groups (n = 15 per group). In the first group, root canals were obturated using the cold lateral condensation technique. In the second group, the Thermafil technique was used to obturate root canals. In the last group, a ProTaper gutta-percha of the same taper as the instrumented root canals was used for root canal obturation. Vertical forces were measured using the device developed for simulation of endodontic treatment. The results showed a statistically significant difference (p = 0.0001) for vertical forces when cold lateral condensation obturation technique was used in comparison to other techniques. No statistically significant difference was found for vertical forces during obturation with Thermafil and ProTaper gutta-percha (p = 0.16). The cold lateral condensation technique exerted higher vertical forces in comparison to the Thermafil and ProTaper obturation techniques.

The effect of frequent removable partial denture wearing on alveolar bone resorption.

AIM: To determine the influence of frequent removable partial denture (RPD) wearing on the alveolar bone density changes around the abutment teeth. METHODS: Fifty examinees of both genders, wearing partial dentures, were included in the study. Thirty one of the examinees (62%) were wearing the dentures 24 hours a day, while nineteen (34%) of them were wearing them only during the day. The changes in the bone density around the abutment teeth were determined by the intraoral microdensitometry method. Standard retroalveolar radiographs were performed twice. The first one before the removable partial denture delivery and the second one after a period of three-month denture wearing. A copper step wedge consisting of five steps (0.1-0.5 mm) was attached to the radiograph in order to calibrate it. Seven points, regions of interest (ROI) close to the root of the abutment tooth, all ten pixels in size, were selected on each radiograph. Grey areas in the regions of interest were measured and converted into the copper step wedge thickness equivalents in order to estimate the change in the alveolar bone density and measure the difference in alveolar bone density between two radiographs. RESULTS: The results indicated that there is not any statistically relevant change (t-value less than 2,011; t(49,0.05) / F less than 4,0426; F0.05(1,48)) in the alveolar bone density depending on the frequency of removable partial denture wearing. CONCLUSION: The frequency of removable partial denture wearing does not cause any changes in the alveolar bone density around the abutment teeth in the period of three-month denture wearing.

Factors influencing a patient's decision to choose the type of treatment to improve dental esthetics.

BACKGROUND/AIM: Interest in dental esthetics has increased rapidly during the last few decades among both patients and dentists, and the creation of a natural dental appearance has become an important task in all fields of dentistry, especially in prosthodontics and restorative dentistry. The aim of this research was to investigate factors influencing a patient's decision to choose the type of treatment to improve dental esthetics. METHODS: A total of 700 Caucasian subjects participated in the cross-sectional study (261 men, 439 women, aged 18-86 years, mean age 46.2 +/- 18.6). The study included clinical examination and a self-administrated questionnaire based on self-perceived esthetics, satisfaction with the appearance of their maxillary anterior teeth and previous dental experience. Multiple logistic regression was used in statistical analysis. RESULTS: Hiding teeth during smile was the most important predictor for choosing fixed prosthetic restorations (OR 9.1), followed by self-perceived bad fixed prosthesis, malpositioned teeth and female gender (OR 2.9, 2.4, and 1.5, respectively). The increase in satisfaction with dental appearance and previous orthodontic therapy reduced chances for seeking prosthetic therapy (each OR 0.4). The significant predictors for bleaching choosing were hiding teeth during smiling, already done bleaching, female gender, lower levels of satisfaction with dental appearance and the absence of the previous orthodontic therapy (OR 5.8, 2.4, 1.8, 0.5 and 0.4, respecitively). Hiding teeth during smile, self-perceived malposition and crowding, and lower levels of satisfaction, were significant predictors for choosing orthodontic treatment (OR 3.1, 2.4, 2.2 and 0.6, respectively). None of current dental statuses was statistically significant predictor for choosing prosthodontic, bleeching nor orthodontic therapy. CONCLUSION: The psychological elements and female gender are the main predictors of seeking dental therapy. Understanding the prevalence of dissatisfaction with the present esthetics and desired treatments to improve esthetics can be a guide for strategies for intervention to improve esthetics.

Vertical force and torque analysis during mechanical preparation of extracted teeth using hand ProTaper instruments.

The purpose was to measure and analyse the vertical force and torque developed in the wider and narrower root canals during hand ProTaper instrumentation. Twenty human incisors were divided in two groups. Upper incisors were experimental model for the wide, while the lower incisors for the narrow root canals. Measurements of the force and torque were done by a device constructed for this purpose. Differences between the groups were statistically analysed by Mann-Whitney U-test with the significance level set to P<0.05. Vertical force in the upper incisors ranged 0.25-2.58 N, while in the lower incisors 0.38-6.94 N. Measured torque in the upper incisors ranged 0.53-12.03 Nmm, while in the lower incisor ranged 0.94-10.0 Nmm. Vertical force and torque were higher in the root canals of smaller diameter. The increase in the contact surface results in increase of the vertical force and torque as well in both narrower and wider root canals.

Electronic root canal length measurement before and after experimentally induced pulpitis and apical periodontitis in dogs.

The aim of the study was to examine the influence of the state of the pulp and apical periodontium on the results of electronic root canal length measurement (ERCLM) with a resistance measuring device in dogs. Pulpitis and apical periodontitis were induced by pulp exposure and contamination by the oral flora in the premolar teeth of six mongrel dogs, comprising four experimental groups (36 root canals). In a control group, measured lengths of teeth with uninfected pulps were performed on the first experimental day (44 root canals). In all animals the ERCLMs were performed on teeth with healthy pulps, and at the end of the experimental period (20, 35, 50 and 65 days) following pulp exposure. The point of measuring canal lengths was the anatomical obstacle above the apical delta. Electronically measured lengths (EML) were compared between each other and with the root canal length established by tactile-sense measurement verified radiographically. The EMLs were less accurate in teeth with healthy pulps and teeth with pulpitis in the third experimental group (dif=2.27 x 2.65 mm(2); t test, p<0.05), while they were most precise after 65 days in teeth with completely necrotic pulp and established chronic apical periodontitis (dif=0.54 x 1.36 mm(2); t test, p>0.05). These results suggest that the state of the pulp and periapical tissue may have an influence on the ERCLM.