Radiographic measurement of residual root thickness in premolars with post preparation

A minimum thickness of 1 mm has been suggested for the residual root wall in post preparation. The objective of this paper is to evaluate the reliability of radiography when used to measure root thickness. In 106 upper first premolars with one and two root canals, post preparations were made with Peeso reamers to a depth in the root equal to the crown length. Bucco-palatal radiographs were taken of each tooth. The films were processed and projected with a magnification of x20. The smallest thickness of the mesial and distal walls of each root at the apical end of the preparation was measured and recorded. The teeth were then cut at the level of the measurement, and the smallest thickness of the proximal walls was measured using a microscope with a micrometric eyepiece. Fourteen percent of the teeth with one root canal and 27% of the teeth with two root canals could not be measured due to blurred radiographic contours. Variance analysis showed a highly significant difference (p < 0.001) when radiographic and anatomical measurements were compared. The radiograph showed greater thicknesses than were actually present and should not therefore be considered to be a reliable method for measuring residual thickness of tooth walls after post preparation.     

ANTIMICROBIAL ACTIVITY OF SODIUM HYPOCHLORITE ASSOCIATED WITH INTRACANAL MEDICATION FOR Candida albicans AND Enterococcus faecalis INOCULATED IN ROOT CANALS

Objective:

The purpose of this study was to evaluate the action of sodium hypochlorite (NaOCl) associated with an intracanal medication against Candida albicans and Enterococcus faecalis inoculated in root canals.

Material and Methods:

Thirty-six human single-rooted teeth with single root canals were used. The canals were contaminated with C. albicans and E. faecalis for 21 days and were then instrumented with 1% NaOCl. The roots were divided into 3 groups (n=12) according to the intracanal medication applied: calcium hydroxide paste, 2% chlorhexidine (CHX) gel, and 2% CHX gel associated with calcium hydroxide. The following collections were made from the root canals: a) initial sample (IS): 21 days after contamination (control), b) S1: after instrumentation, c) S2: 14 days after intracanal medication placement; S3: 7 days after intracanal medication removal. The results were analyzed statistically by the Kruskal-Wallis test at 5% significance level.

Results and Conclusions:

Both 1% NaOCl irrigation and the intracanal medications were effective in eliminating E. faecalis and C. albicans inoculated in root canals.     

Onset and duration periods of articaine and lidocaine on maxillary infiltration.

OBJECTIVES: The aim of this study was to compare the onset and duration of pulpal anesthesia by maxillary infiltration using 2% lidocaine with 1:100,000 epinephrine, 4% articaine with 1:200,000 epinephrine, and 4% articaine with 1:100,000 epinephrine. METHOD AND MATERIALS: Twenty healthy patients randomly received 1.8 mL of one of the three local anesthetics during operative dentistry procedures of low complexity on three maxillary posterior teeth. Onset and duration were determined using an electric pulp tester. RESULTS: The mean values for pulpal onset were 2.8, 1.6, and 1.4 minutes and for pulpal duration were 39.2, 56.7, and 66.3 minutes, respectively, for 2% lidocaine with 1:100,000 epinephrine, 4% articaine with 1:200,000 epinephrine, and 4% articaine with 1:100,000 epinephrine. Statistical analysis by the Kruskal-Wallis nonparametric test showed significant differences with better results (shorter onset and longer duration periods) for both articaine solutions compared with the lidocaine solution. Although 4% articaine with 1:100,000 epinephrine clinically presented the shortest onset and the longest duration periods, there was no statistically significant difference between the articaine solutions. CONCLUSION: Both articaine solutions produced shorter onset and longer duration of pulpal anesthesia by maxillary infiltration than the lidocaine solution did. Statistical analysis did not confirm better clinical results of 4% articaine with 1:100,000 epinephrine than with 4% articaine with 1:200,000 epinephrine.     

Stability of skeletal Class III malocclusion after combined maxillary and mandibular procedures

The aim of this study was to evaluate the skeletal stability and time course of postoperative changes after surgical correction of skeletal Class III malocclusion. Combined maxillary and mandibular procedures were performed in 40 consecutive patients. Bilateral sagittal split osteotomy stabilized with wire osteosynthesis for mandibular setback and low-level Le Fort I osteotomy stabilized with plates and screws for maxillary advancement were performed. Maxillomandibular fixation (MMF) was in place for 6 weeks. Lateral cephalograms were taken before surgery, immediately postoperatively, 8 weeks after surgery, and 1 year postoperatively. Patients were divided into 2 groups according to vertical maxillary movement at surgery: a maxilla-up group with upward movement of the posterior nasal spine of 2 mm or more (group 1, n = 22), and a minimal vertical change group with less than 2 mm of vertical repositioning (group 2, n = 18). The results indicate that surgical correction of Class III malocclusion with combined maxillary and mandibular osteotomies appears to be fairly stable. One year postsurgery, maxillary stability was excellent, with a mean horizontal relapse at point A that represented 10.7% of maxillary advancement in group 1 and 13.4% in group 2. In the vertical plane, maxillary stability was also excellent, with a mean of 0.18 mm of superior repositioning at point A for group 1 and 1.19 mm for group 2. The mandible relapsed a mean of 2.97 mm horizontally at pogonion in group 1 (62% of mandibular setback) and 3.41 mm (49.7% of setback) in group 2. Bilateral sagittal split osteotomy with wire osteosynthesis and MMF was not as stable as maxillary advancement and accounted for most of the total horizontal relapse (almost 85%) observed. A trend to relapse was observed for maxillary advancement greater than 6 mm, while the single variable accounting for mandibular relapse in group 1 was the amount of surgical setback. Clockwise rotation of the ascending ramus at surgery was not correlated with mandibular relapse in relation to the type of fixation performed and therefore does not seem to be responsible for relapse.     

Hydrophobicity of graphene as a driving force for inhibiting biofilm formation of pathogenic bacteria and fungi

Objective

To evaluate the surface and wettability characteristics and the microbial biofilm interaction of graphene coating on titanium.

An electromyographic study of masseter and anterior temporalis muscles in extra-articular myogenous TMJ pain patients compared to an asymptomatic and normal population

The purpose of this study was to evaluate the effectiveness of the therapy with a centric relation stabilization appliance (CRSA) in patients with temporomandibular disorders of myogenous origin by electromyography and compare the results with two asymptomatic control groups. Three groups of 20 patients each were selected for the study. Electromyography (EMG) of masseter and anterior temporalis muscles was performed during mandibular rest position. In the treated group, the occlusal appliance reduced the electrical activity of the analyzed muscles at right and left sides (p<0.0001), and equilibrated muscular activity between right and left sides (p<0.0001), reaching values close to the control groups. Although there was not a statistically significant difference, the normal control group presented lower EMG values than control group II and presented the lowest asymmetry index of all subjects. More than 85% of all subjects, including the controls, demonstrated a statistically significant temporal anterior activity prevalence (p<0.0001). Treatment with the CRSA reduced the activity index, although the prevalence of the temporal muscle over the masseter was maintained. The significant laterodeviating (torque) effect found in the temporomandibular disorder patients was reduced after treatment. No side prevalence was found in the control groups.     

Dental caries and microbial acid production in twins

OBJECTIVE: To determine the relative contribution of genetic and environmental stimuli on dental caries traits and microbial acid production in a twin model. METHODS: Dental caries examinations and microbial acid production assays were performed on 388 pairs of twins 1.5-8 years old from the city of Montes Claros, Brazil. Genotyping 8 polymorphic DNA markers determined zygosity. Caries exams followed NIDCR criteria modified to distinguish white spot lesions from cavitated lesions. Surface-based caries prevalence rates (SBCPR) were computed and lesion severity was determined by a weighted index (LSI). Biofilm samples were collected from the tongue using a lactic acid indicator swab. Assay scores were categorized based on acid formation as 1 = low, 2 = medium, and 3 = high. Heritability analyses were performed using the SOLAR software package. RESULTS: Heritability estimates for SBCPRs, LSI and for microbial acid production were H = 76.3 (p < 0.001), H = 70.6 (p < 0.001), H = 16.2 (p = 0.0078), respectively. Treating microbial acid production as a covariate in the SBCPR and LSI models did not significantly alter the heritability estimates, i.e. H = 76.5 (p < 0.001) and H = 70.8 (p < 0.001), respectively. CONCLUSIONS: These results suggest that variation in dental caries surface traits has a significant genetic contribution and that microbial acid production is modulated by the environment.     

Maternal periodontitis as a potential risk variable for preeclampsia: a case-control study

BACKGROUND: Association studies between maternal periodontitis and an elevated risk for preeclampsia have shown conflicting results. The aims of the present case-control study were: 1) to evaluate the association between maternal periodontitis and preeclampsia before and after matching, assessing confounding and interaction; and 2) to evaluate the influence of the extent and severity of periodontal parameters, bleeding on probing (BOP), probing depth (PD), and clinical attachment loss (CAL), in association with preeclampsia. METHODS: Initially, 1,206 Brazilian women were included and divided into a control group (1,042 non-preeclamptic women who gave birth to infants with adequate gestational age and birth weight) and a case group (164 preeclamptic women). Further, 125 preeclamptic women were matched according to age, chronic hypertension, and primiparity to 375 non-preeclamptic women randomly selected from the control group. Maternal periodontitis was defined as PD > or =4 mm and CAL > or =3 mm at the same site in at least four teeth. The effect of variables of interest and confounding were assessed by univariate and multivariate analysis. RESULTS: After controlling for confounders, maternal periodontitis was included in the multivariate final model (odds ratio [OR] = 1.94; 95% confidence interval [CI]: 1.37 to 2.77; P <0.001) and remained associated with preeclampsia after matching (OR = 1.52; 95% CI: 1.01 to 2.29; P = 0.045). The odds of preeclampsia were associated with an increase in the number of sites with BOP and PD and CAL > or =4 mm. CONCLUSION: Maternal periodontitis is a risk factor associated with preeclampsia, emphasizing the importance of periodontal care in prenatal programs.     

Ultrasound bone cutting for surgically assisted rapid maxillary expansion under local anesthesia. Preliminary results

Surgically assisted rapid maxillary expansion (SARME) is a well-established therapy for correction of maxillary transverse deficiency in adults, when consolidation of sutures has just been completed. It can be performed either under general or under local anesthesia and it can be accomplished with many surgical techniques. One of the most critical steps of SARME is the detachment of the pterygo-maxillary junction, due to the risks connected to such procedure. When required to obtain specific expansion patterns, the pterygo-maxillary separation has been suggested until now only for interventions under general anesthesia, due to the dangerousness and the rawness of this surgical step in awake patients. The authors introduce the use of an ultrasonic bone-cutting device to perform all osteotomic steps of SARME under local anesthesia on an outpatient basis, including pterygo-maxillary detachment. This ultrasonic device is unique in that the osteotomic action occurs only when the tool is employed on mineralized tissues, while it stops on soft tissues. It works in a linear pattern of vibration and it allows precise osteotomies without producing any heat damage to osteotomic surfaces and without any dangerous hammer-related stroke. Due to its precision and safety, this device named Piezosurgery, allows patients to undergo all the steps of SARME under local anesthesia, also without hospitalization.