Shaping ability of progressive versus constant taper instruments in curved root canals of extracted teeth

AIM: To compare the shaping ability of progressive versus constant taper shaft instruments in curved root canals of extracted human teeth. METHODOLOGY: A total of 40 root canals of mandibular molars with curvatures ranging between 20 degrees and 40 degrees were divided into two groups of 20 canals each and embedded in a muffle system. The root canals sectioned horizontally at three levels before preparation and then remounted into the mould. All root canals were prepared with ProTaper (progressive taper) or Hero Shaper (constant taper) instruments. Pre- and post-instrumentation radiographs and cross-sectional images were obtained. The parameters evaluated were: working safety (instrument failure, apical blockage and loss of working length) and shaping ability (straightening, cross-sectional area, transportation and centring ability). The data were analysed statistically using Student's t-test. RESULTS: No instrument fractured during preparation. One Hero Shaper instrument permanently deformed. Both instrument systems maintained working length well. The canals prepared with Hero Shaper instruments were straightened to a lesser degree (P < 0.05). ProTaper instruments removed more dentine in the coronal and the middle sections of the canals. Canals prepared with Hero Shaper instruments had less transportation (P < 0.01) and better centring ability (P < 0.05) in the apical section. CONCLUSIONS: Both instrument systems were safe to use and maintained working length well. The canals prepared with Hero Shaper had less transportation and were better centred in the apical region, possibly because their smaller taper reduced instrument stiffness.     

Pharmacologic behavior management of pediatric dental patients diagnosed with attention deficit disorder/attention deficit hyperactivity disorder

PURPOSE: The purpose of this study was to conduct a survey of Texas pediatric dentists to determine: (1) the percentage of patients they treat with attention deficit disorder (ADD)/attention deficit hyperactivity disorder (ADHD); (2) the behavior management techniques that are utilized to treat their patients who suffer from ADD/ADHD; and (3) the relative success rates of these techniques in their practices. METHODS: A 17-question, single-answer, multiple choice survey was mailed to 343 Texas pediatric dentists. The mailing list was obtained from American Academy of Pediatric Dentistry and Texas Academy of Pediatric Dentistry member rosters. One mailing was sent, including a self-addressed stomped envelope, for returned responses. RESULTS: A 54% response rate (186 surveys) revealed that nitrous oxide was the most frequently used pharmacologic behavior management technique; however, demerol/promethazine/nitrous oxide was rated as effective most often for treating ADD/ADHD patients. CONCLUSIONS: Practitioners believe the incidence of attention deficit disorder/attention deficit hyperactivity disorder is increasing, and they are familiar with the medications used to treat the conditions. Texas pediatric dentists are using a variety of sedation techniques and are interested in developing guidelines for sedation of these patients.     

Talon cusps: conservative management

Talons cusp is an uncommon developmental dental anomaly characterized by presence of an accessory cusp like structure projecting from tooth neck towards incisal edge. This anomaly commonly affects permanent dentition than primary dentition. This article describes early diagnosis and management of two patients with talons cusp. Conservative treatment by selective grinding, followed by fluoride varnish application was done. The patients were followed up for one year without any complications. This indicates conservative means of management to be the most desirable way of managing such anomalies.     

No evidence for a role of CRISPLD2 in non-syndromic cleft lip with or without cleft palate in an Italian population

Non-syndromic cleft lip with or without cleft palate (NSCLP) is a malformation with variable phenotypes, resulting from a mixture of genetic and environmental factors. Some studies have supported a role for the 16q24 region and its candidate gene, CRISPLD2, in clefting. A replication study is necessary to confirm these findings. The aim of the present study was to test, by genetic linkage and association analyses, whether the candidate gene, CRISPLD2, represents a risk factor for NSCLP. The analysis of 39 multigenerational families provided formal exclusion of a linkage between NSCLP and the CRISPLD2 locus under different genetic models and non-parametric analyses. The family-based study of 239 unrelated probands and their parents revealed no association between any particular allele or haplotype and NSCLP. Therefore, the present investigation did not support the hypothesis of the involvement of CRISPLD2 in NSCLP malformation, at least with regard to the Italian population.     

Can anti‐erosion dentifrices also provide effective plaque control?

To cite this article:
Int J Dent Hygiene 9 , 2011; 223–228
DOI: 10.1111/j.1601‐5037.2010.00480.x
Bellamy PG, Prendergast M, Strand R, Yu Z, Day TN, Barker ML, Mussett AJ. Can anti‐erosion dentifrices also provide effective plaque control? Abstract: Objective: While gingivitis and caries continue to be prevalent issues, there is growing concern about dental erosion induced by dietary acids. An oral hygiene product that protects against all these conditions would be beneficial. This study investigated the potential of two anti‐erosion dentifrices to inhibit plaque. Methods: This was a randomized, three‐period, two‐treatment, double‐blind, crossover study evaluating a stannous chloride/sodium fluoride dentifrice (SnCl₂/NaF, blend‐a‐med^® Pro Expert) and a popular anti‐erosion dentifrice (NaF, Sensodyne^® ProNamel^?). During Period 3, subjects were randomized to repeat one treatment to evaluate any product carryover effects. Each treatment period was 17 days. Test dentifrices were used with a standard manual toothbrush. Digital plaque image analysis (DPIA) was employed at the end of each period to evaluate plaque levels (i) overnight (am prebrush); (ii) post‐brushing with the test product (am post‐brush); and (iii) mid‐afternoon (pm ). Analysis was conducted via an objective computer algorithm, which calculated total area of visible plaque. Results: Twenty‐seven subjects completed the study. At all time points, subjects had statistically significantly (P ≤ 0.0001) lower plaque levels after using the SnCl₂/NaF dentifrice than the NaF dentifrice. The antiplaque benefit for the SnCl₂/NaF dentifrice versus the NaF dentifrice was: am prebrush = 26.0%; am post‐brushing = 27.9%; pm = 25.7%. Conclusions: The SnCl₂/NaF dentifrice provided significantly greater daytime and overnight plaque inhibition than the NaF toothpaste. When recommending dentifrice to patients susceptible to dental erosion, clinicians can consider one that also inhibits plaque.     

The influence of simulated masticatory loading regimes on the bi-axial flexure strength and reliability of a Y-TZP dental ceramic

OBJECTIVES: The purpose of the current study was to examine the influence of simulated masticatory loading regimes, to which all-ceramic crown or bridge restorations will routinely be subjected during their service-life, on the performance of a yttria-stabilised tetragonal zirconia polycrystalline (Y-TZP) dental ceramic. METHODS: Ten sets of 30 Y-TZP ceramic discs (13 mm diameter, 1.48-1.54 mm thickness) supplied by the manufacturer were randomly selected. Six groups were loaded for 2000 cycles at 500 N (383-420 MPa), 700N (536-588 MPa) and 800 N (613-672 MPa) with three groups maintained dry and the remaining three groups loaded while immersed in water at 37+/-1 degrees C. A further two groups underwent extended simulated masticatory loading regimes at 80 N (61-67 MPa) for 10(4) and 10(5)cycles under dry conditions. The mean bi-axial flexure strengths, standard deviations and associated Weibull moduli (m) were determined. The surface hardness was also determined using the Vickers hardness indentation technique. RESULTS: No significant difference (P>0.05) was identified in the bi-axial flexure strength of the simulated masticatory loading regimes and the control specimens loaded dry or wet. A significant increase in m was identified for the Y-TZP specimens following loading while immersed in water (8.6+/-1.6, 8.5+/-1.6 and 10.3+/-1.9) compared with the control (7.1+/-1.3). However, the extended loading regime to 10(5)cycles resulted in a significant reduction in the m of the Y-TZP specimens (5.3+/-1.0) compared with the control. Localised areas of increased surface hardness were identified to occur directly beneath the spherical indenter. CONCLUSIONS: The occurrence of localised areas of increased surface hardness could be the result of either a transformation toughening mechanism or crushing and densification of the material beneath the indentor manifested as the formation of a surface layer of compressive stresses that counteracted the tensile field generated at the tip of a propagating crack which increased the Weibull modulus of the Y-TZP specimens. The reduced reliability of the Y-TZP specimens loaded to 80 N for 10(5)cycles was associated with the accumulation of subcritical damage as a result of the extended nature of loading.     

Microcomputed tomography used in the analysis of the morphology of root canals in extracted wisdom teeth

Microcomputed tomography is a new technique for the non-destructive study of porous biological materials. We examined 11 wisdom teeth that had been removed prophylactically by microcomputed tomography operating in the cone beam mode. The two-dimensional sections of the teeth were reconstructed with surface rendering software to provide three-dimensional models that were observed and handled in virtual reality. The tooth itself, or the pulp chamber and canals, can be reconstructed and observed separately or simultaneously. Many teeth looked dystrophic with abnormal distributions of roots and canals. Microcomputed tomography seems to be a promising way of studying dental anatomy.     

Compressive shear bond strength of core buildup materials

New tooth-colored restorative materials have been developed with the goal of replacing amalgam. These restoratives are marketed as packable composite and ormocer. The purpose of the present study was to compare the compressive shear bond strengths of these new materials with that of hybrid composite and amalgam as core materials. Standardized core buildups were made on four groups of extracted molars, with 10 teeth per group. Three tooth-colored restorative materials (Filtek Z 250, Filtek P 60, and Definite) and an amalgam (SDI Permite) were used. Specimens were placed in a special jig at a 45-degree angle. The compressive shear bond strength was obtained using a universal testing machine. The Kruskal-Wallis test was used to compare the groups, and pairwise comparisons were made by Mann-Whitney U test (P < .05). Filtek P 60, a packable composite resin, had the greatest compressive shear bond strength values in all instances, and the ormocer (Definite) had the lowest. The strengths of packable composite, hybrid composite, and amalgam as core materials were not significantly different (P > .05).     

General dentists' evaluation of anesthesia sedation education in U.S. dental schools

To assess the quality and quantity of sedation education in U.S. dental schools, a prospective, questionnaire-based survey was administered to general dental practitioners who graduated in 2003. Questionnaires were sent via facsimile to recent dental graduates using a list obtained through the American Dental Association. The response rate was 54 percent; 718 of the 1,328 nine-question surveys were returned. The response to the questionnaires indicates a perceived need for sedation care by the majority of recent graduates and low overall satisfaction with the quality of sedation education in U.S. dental schools. The general consensus of most 2003 dental school graduates is that they have gained little or no hands-on experience in sedation techniques and would have supported an increase in tuition and fees if an institution were to offer more efficient sedation training. With increased popularity and high patient demand for sedation techniques, the new dentist feels a need for sedation education before graduation.