The influence of facial types on the morphology and location of the greater palatine foramen: a CBCT study.

OBJECTIVE: This study aimed to assess the morphology and location of the great palatine foramen (GPF) of different facial types using cone beam computed tomography (CBCT) scans. METHODS: Sixty CBCT scans were divided into: brachyfacial (n = 20), dolichofacial (n = 20) and mesofacial (n = 20) using Ricketts' VERT index for the determination of cephalometric facial type and imported into ImageJ software. GPF shape was characterized as: round, elongated in the anteroposterior direction (EAP), or elongated in the latero-medial direction (ELM). The distances between the GPF and the palatine suture (PS), the center of the GPF and the center incisive foramen (IF), the GPF and the palatine alveolar ridge (PAR), right side GPF (GPFr) and left side (GPFl) GPFs; and the angles formed from the intersection of the GPF, IF and PS were assessed. The position of the GPF was evaluated in relation to the molars. RESULTS: GPFr and GPFl mean distances from PAR presented higher values for dolichofacial patients (p < 0.05). GPFr and GPFl location distally to the third molar (3 M) was higher for brachyfacial type, while their location distally to the second molar was higher for mesofacial and between the mesial and distal surfaces of the 3 M for dolichofacial (p < 0.05). CONCLUSIONS: The GPF was more distant from the PAR in the dolichofacial-type group. The location of the GPF in relation to the molars varied according to the facial type. However, the morphology of the GPF was similar in the three facial types, and the elongated in the anteroposterior direction morphology was more frequent.

Adaptation of gutta percha to oval canals: a cone beam computed tomographic analysis.

This study evaluated the influence of different instrumentation techniques on the adaptation of gutta percha cones in oval-shaped root canals. A total of 90 human single-rooted teeth were divided into groups according to the instrumentation technique that was used: group M, manual; group OM, hybrid: oscillatory plus manual; group PT, rotary (ProTaper Universal); group OPT, hybrid: oscillatory plus rotary (ProTaper Universal); group MT, rotary (Mtwo); and group OMT, hybrid: oscillatory plus rotary (Mtwo). After a single gutta percha cone was adapted to the canal, cone beam computed tomography was utilized to perform assessments at areas of greater contact of gutta percha to root canal walls. The adaptation was rated as ideal, satisfactory, minimally acceptable, or unsatisfactory. The frequency of ideal adaptation of the cone to the 4 canal walls varied from 26.67% (groups OMT and PT) to 73.33% (group MT); the differences between group MT and groups PT and OMT were statistically significant (P < 0.05). The mean area of the canal preparation without adaptation (contact) of the cone varied from 0.06 mm² (group MT) to 0.41 mm² (group OMT). The results showed that an instrumentation technique using the Mtwo system provided the best adaptation of the .04 gutta percha cones to anatomically oval root canals.

Prevalence of bifid mandibular canals by cone beam computed tomography.

PURPOSE: The aim of this study was to evaluate the prevalence of bifid mandibular canals (BMC) by cone beam computed tomography (CBCT). MATERIALS AND METHODS: We examined CT scans from 300 patients both male and female, aged 25 to 87 years. The subjects were divided into groups according to gender, male group (MG) and female group (FG) as well as subgroups according to the side, right (R) and left (L). Tomographic acquisitions were performed on the device I-Cat ® Classic. Image analysis was performed on the XoranCat ® software of the equipment itself, aided by image filters associated with transverse, oblique, and panoramic reconstruction cuts for analysis of the BMC. The results were displayed as descriptive analysis of the values and comparisons between factors were performed using ANOVA at a significance level of 95 %. RESULTS: BMC was observed in 80 cases (26.67 %), of which, 39 (48.75 %) were in males and 41 (51.25 %) in females; no difference was seen between genders, neither by affected side, although the right side was more frequently affected (66.67 %) when both genders were combined. CONCLUSION: The prevalence of BMC is significant and should not be overlooked.

Low dose propranolol decreases orthodontic movement.

OBJECTIVE: Low dose propranolol has previously been demonstrated to suppress bone remodelling. Therefore, its effect on orthodontic movement was tested. DESIGN: Rats were assigned as follows (n=5): animals with no orthodontic appliance (G1); the remaining groups were fitted with a Ni-Ti closed-coil spring ligated to the upper left first molar and connected to the incisors using metal and resin and received vehicle only (G2), 0.1mg/kg (G3) or 20mg/kg (G4) of propranolol orally. Cone Beam Computed Tomography was performed using high resolution for image capture. The distance between the first and second upper molars, both with and without the orthodontic appliance, was measured in millimetres. Gingival tissue was harvested and assessed for IL-1ß and IL-6 using ELISA and for ICAM-1 and RANKL by Western blotting. RESULTS: The orthodontic appliance induced a significant tooth movement in G2 when compared to the animals without an orthodontic appliance (G1) (p<0.05). The animals from G3 showed a significantly reduction in tooth movement (p<0.05) when compared with rats from G2. Animals treated with 20mg/kg of propranolol (G4) showed tooth movement similar to that of G2. The reduced tooth movement observed in the animals treated with 0.1mg/kg of propranolol (G3) occurred due to decreased amounts of IL-1ß and IL-6, in addition to lower ICAM-1 and RANKL expression. CONCLUSIONS: Low dose propranolol inhibits bone remodelling and orthodontic movement.

Study of the bismuth oxide concentration required to provide Portland cement with adequate radiopacity for endodontic use.

OBJECTIVE: The purpose of this study was to determine the ideal concentration of bismuth oxide in white Portland cement to provide it with sufficient radiopacity for use as an endodontic material (ADA specification #57). STUDY DESIGN: 2-mm thick standardized test specimens of white MTA and of white Portland cement, as controls, and of white Portland cement with the experimental addition of 5%, 10%, 15%, 20%, 25% or 30% of bismuth oxide were radiographed and compared with various thicknesses of pure aluminum, using optic density to determine the observed grayscale levels of radiopacity in a scale ranging from 0 to 255. The data was submitted to ANOVA (p<0.05) and the Ryan-Einot-Gabriel-Welch and Quiot test (REGWQ) for multiple comparison of the means. RESULTS: White Portland cement with 0%, 5%, 10%, 15%, 20%, 25% and 30% of bismuth oxide presented mean readings of 63.3, 95.7, 110.7, 142.7, 151.3, 161.0 and 180.0 respectively. MTA presented a mean reading of 157.3. The readings of MTA and white Portland cement with 15% bismuth oxide did not differ significantly from the reading observed for a thickness of 4 mm of aluminum (145.3), which is considered ideal for a test specimen by ADA specification #57 (2 mm above the thickness of the test specimen). CONCLUSION: White MTA and white Portland cement with 15% bismuth oxide presented the radiopacity required for an endodontic cement.