Electromyographic Evaluation of Superior Orbicularis Oris Muscle Activity in Patients With Complete Cleft Lip and Cleft Palate Before and After Vestibuloplasty Using Carbon Dioxide Laser Therapy.

Introduction: Cleft lip and cleft palate are the most typical congenital craniofacial anomalies. Post-surgical scars in cleft lip patients can cause shallow upper labial sulcus and reduced upper lip length. The aim of the present study was to evaluate the impact of CO2 laser vestibuloplasty on the electromyographical (EMG) activity of patients' superior orbicularis oris muscle, depth of labial sulcus, and upper lip length, and their satisfaction with the procedure and its results. The CO2 laser is an effective vestibuloplasty procedure, is safe and highly acceptable for patients, and has little effect on muscle contraction. Methods: A total of 15 cleft lip and cleft palate patients participated in this study. Vestibuloplasty was performed using carbon dioxide laser therapy in one session in such a way that EMG activity in the upper lip muscle, depth of labial sulcus, and upper lip length were measured two times: before (T0) and twenty days after surgery (T1). Patients' satisfaction surveys were also recorded using a patient questionnaire at T1. Results: The mean values for vestibular depth at T0 and T1 were 2.00±1.71 and 4.52±1.43, respectively. The mean values for upper lip length at T0 and T1 were 6.90±2.32 and 8.00±2.40, respectively, suggesting a significant change in vestibular depth and upper lip length. The vestibular depth and upper lip length significantly increased at T1. The EMG recording of the upper lip muscle experienced a moderate decrease after laser treatment, both at rest and at maximum lip protrusion. Moreover, patients' satisfaction with the surgical procedure was 82% positive. Conclusion: Using the CO2 laser increased the vestibular depth and upper lip length successfully and made small changes in the EMG activity of the superior orbicularis oris.

Evaluation of the effect of tooth type and canal configuration on crown size in mandibular premolars by cone-beam computed tomography.

INTRODUCTION: To achieve success in treatment, one cannot ignore the knowledge of pulp anatomy. Mandibular premolars are considered to be the most difficult teeth for endodontic therapy due to high variability in their canal morphology. It is possible that a relation exists between the crown size and the number of extra canals in these teeth, so this in vitro study aims to investigate the relationship between the crown size and the uncommon morphology of mandibular premolars using Cone-Beam Computed Tomography (CBCT). MATERIALS AND METHODS: Eighty three extracted mandibular human premolars were exposed to radiation using the CBCT device. Root canal configuration was categorized according to the Vertucci's classification. The crown size was measured in three axial, coronal and sagittal sections. Finally, the relation between these two factors was evaluated with variance analysis (two-way ANOVA) and chi-square. RESULTS: The most common canal type in the mandibular first and second premolars are type I (71% and 76%, respectively), followed by type V (29% and 22%, respectively). No significant relationship was found between the crown size and extra canals in mandibular premolars (P>0.05). CONCLUSION: In this in vitro study, the average crown size in two-canalled second premolars was less than that in first premolars with a single canal; although the difference was not statistically significant. The research hypothesis was therefore rejected in both first and second mandibular premolars.