Fracture strength of preformed zirconia crown and new custom-made zirconia crown for the restoration of deciduous molars: in vitro study.

PURPOSE: Preformed metal crown (PMC) were considered as the best method of restoring primary molars. In recent years, dentistry has seen the emergence of esthetic full-coverage restorative alternatives that gave better results but their ability to manipulate the size, shape, and fit is very limited. The milled zirconia crown is a new alternative for the restoration of deciduous teeth, but the mechanical properties of these restorations need to be tested. AIM: To assess and compare the force required to fracture on two posterior pedodontics crowns: a prefabricated Zirconia crowns (PZC) (NuSmile Zr Zirconia®) and a new custom-made zirconia crown (also called Zirkid©) on a freshly extracted deciduous molars. METHODS: Thirty freshly extracted deciduous molars were selected and were randomized into two groups: (1) molars prepared to receive the PZC and (2) molars prepared to receive the milled zirconia crowns. All pediatric crowns were cemented with glass ionomer and the samples were placed in the thermocycling machine for thermal aging of 1000 cycles. Mechanical compression forces were applied using the Universal Testing Machine until fracture of the crowns. The force required to fracture were evaluated. Since variable was normally distributed with Kolmogorov-Smirnov test, Student t test was used for statistical comparison. RESULTS: This study showed that the mean fracture force was significantly elevated with zirconia crowns made with Zirkid© (2888.6 ± 1060.2 N) compared to NuSmile Zr crowns (646.5 ± 223.9 N) (p value < 0.001). CONCLUSION: Considering the limitations of the present in vitro study, further in vitro and in vivo studies are required to support the use of Zirkid© in primary molar teeth restorations and to assess others mechanical properties.

Randomized Clinical Trial of a Self-Adhering Flowable Composite for Class I Restorations: 2-Year Results.

Objectives. To compare the clinical performances of a self-adhering resin composite and a conventional flowable composite with a self-etch bonding system on permanent molars. The influence of using rubber dam versus cotton roll isolation was also investigated. Materials and Methods. Patients aged between 6 and 12 years and presenting at least two permanent molars in need of small class I restorations were selected. Thirty-four pairs of restorations were randomly placed by the same operator. Fifteen patients were treated under rubber dam and nineteen using cotton rolls isolation and saliva ejector. They were evaluated according to the modified USPHS criteria at baseline, 6 months, and 1 and 2 years by two independent evaluators. Results. All patients attended the two-year recall. For all measured variables, there was no significant difference between rubber dam and cotton after 2 years of restoration with Premise Flowable or Vertise Flow (p value > 0.05). The percentage of restorations scored alpha decreased significantly over time with Premise Flowable and Vertise Flow for marginal adaptation and surface texture as well as marginal discoloration while it did not vary significantly for color matching. After 2 years, Vertise Flow showed a similar behaviour to the Premise Flowable used with a self-adhesive resin system.

Association between adherence, treatment satisfaction and illness perception in hypertensive patients.

The relationship between adherence to antihypertension medications, treatment satisfaction and illness perception has not been studied so far. The primary objective of this study was to examine the association between adherence to medication, treatment satisfaction and illness perception in Lebanese hypertensive patients. The relation between medication adherence and blood pressure (BP) control was also assessed. In this cross-sectional study, patients were recruited from the physician's practice offices and community pharmacies in Beirut. Patients who had been treated for hypertension for at least 3 months were invited to participate in the study; they completed three questionnaires: the 8-item Morisky Medication Adherence Scale (MMAS-8), the Treatment Satisfaction Questionnaire for Medication (TSQM-4) and the Brief Illness Perception Questionnaire (BIPQ). BP was also measured and recorded. A total of 117 subjects were included, of whom 29.1% had poor adherence to their antihypertension treatment (MMAS-8 scores<6). The odds of having well-controlled hypertension was 3.5 times higher in patients with high adherence compared with patients with poor adherence (P=0.010). Treatment satisfaction was significantly greater in patients with good adherence (P<0.001). Neither socio-demographic, disease- nor drug-related characteristics of the participants were significantly associated with medication adherence. As for illness perception, even though the mean BIPQ score of adherent participants was lower than the mean score of non-adherent participants, this difference did not reach statistical significance. In conclusion, treatment satisfaction was found to be a predictor of adherence. Studies are needed to determine whether interventions to increase satisfaction can improve adherence and BP control.

[Status of health and oral health of the elderly population in Lebanon]. / État des lieux sanitaire et bucco-dentaire de la population gériatrique libanaise.

Lebanon is in demographic transition as more people reach increasingly older age; 10% of the population in Lebanon is elderly. The incidence of chronic diseases and oral diseases increases significantly with age. However, 55% of the elderly have no health insurance and 82% have no dental insurance. Both noncommunicable diseases (NCDs) and oral diseases are a major health burden in the country and share the same risk factors. The WHO strategy for prevention and control of noncommunicable diseases should therefore be a new approach for the prevention and control of dental diseases among Lebanese elderly. This paper aims to increase the awareness of the medical community in Lebanon about the interrelationship between general and oral health in the elderly and concludes with the need for the Ministry of Health to develop policies and national action plans against NCDs to reduce not only mortality from NCDs but also morbidity from oral diseases.

Effects of three nickel titanium instrument systems on root canal geometry assessed by micro-computed tomography.

AIM: To compare and evaluate the shaping ability of several nickel titanium instrument systems with different motions: two reciprocating single-file systems (Reciproc and WaveOne) and one continuous rotation/reciprocation full-sequence system [Twisted File (TF) Adaptive] using micro-computed tomography. METHODOLOGY: A total of forty-eight mesial canals of mandibular molars with two separate root canals and severe angles of curvature were selected. Canals were divided randomly to one of three experimental groups: group 1, reciprocating instrumentation with Reciproc R25, group 2, reciprocating with the Primary WaveOne file and group 3 'Adaptive Rotary Motion' with Twisted Files. Each group consisted of 16 root canals. Canals were scanned before and after root canal preparation, with a resolution of 20 µm using a micro-computed tomography system. The following parameters were assessed: changes in dentine volume, percentage of unshaped canal walls, degree of canal transportation and centring ability. Data were analysed using analysis of variance and Tukey's post hoc tests test to explore a significant difference in mean dentine removal, mean percentage of noninstrumented canals, mean degree of canal transportation and centring ratio between groups in the apical third and along the entire root canal. The level of significance was set at α = 0.05. RESULTS: Preoperatively, there were no differences regarding root canal curvature and volume between experimental groups (P > 0.05). Overall instrumentation led to enlarged canal shapes with no evidence of preparation errors. None of the three groups was able to shape completely the root canal system. Mean dentine removal along the entire canal and in the apical third was significantly higher with Reciproc when compared with TF Adaptive and WaveOne (P = 0.013). Mean degree of canal transportation was significantly lower with TF Adaptive (P < 0.0001) followed by WaveOne and highest with Reciproc in the apical third and along the entire root canal. CONCLUSIONS: None of the NiTi systems was able to instrument completely the entire root canal. Reciprocation and Adaptive Motions were found to cut dentine efficiently to full working length, with no procedural errors. The TF Adaptive system maintained the original canal anatomy with less canal transportation and better centring ability.

Cyclic fatigue analysis of twisted file rotary NiTi instruments used in reciprocating motion.

AIM: To evaluate the cyclic fatigue fracture resistance of engine-driven twisted file (TF) instruments under reciprocating movement. METHODOLOGY: A sample of 30 size 25, 0.08 taper NiTi TF instruments was tested in a simulated canal with 60˚ angle of curvature and a 3 mm radius. During mechanical testing, different movement kinematics were used at a constant speed, which resulted in three experimental groups (each group n = 10). The instruments from the first group (G1) were rotated until fracture occurred. The instruments in the second (G2) and third group (G3) were driven under reciprocating movement with different angles of reciprocation. The time of fracture for each instrument was measured, and statistical analysis was performed using one-way analysis of variance followed by Tukey's Honestly Significant Different test. RESULTS: Reciprocating movement resulted in a significantly longer cyclic fatigue life (P < 0.0001) when compared with continuous rotation. No difference was found between reciprocation 150° clockwise/30° counterclockwise (CW/CCW) and 30° CW/150° CCW. CONCLUSIONS: The reciprocating movement was associated with an extended cyclic fatigue life of the TF size 0.25, 0.08 taper instruments in comparison with conventional rotation.