Rose D. Sheats

Effect of a resorbable bone graft material on orthodontic tooth movement through surgical defects in the cat mandible

beta-Tricalcium phosphate ceramic, a resorbable synthetic bone material, was implanted into surgically created alveolar defects mesial to the mandibular first premolars of 12 adult male cats. Similar defects on the contralateral side were allowed to heal naturally. Six weeks later, nickel-titanium coiled springs were ligated between the mandibular canine and first premolar on both sides and activated to deliver 100 g of force. The distance between the canine and first premolar was measured with dial calipers at 0, 3, 6, and 9 weeks after appliance placement. Regression analysis of amount of tooth movement between the two teeth showed no significant difference between grafted and control sides. This suggests that placement of a resorbable synthetic bone material may have useful applications in situations where loss of alveolar width following extractions may compromise orthodontic tooth movement.

A novel biomechanical model assessing continuous orthodontic archwire activation

INTRODUCTION The biomechanics of a continuous archwire inserted into multiple orthodontic brackets is poorly understood. The purpose of this research was to apply the birth-death technique to simulate the insertion of an orthodontic wire and the consequent transfer of forces to the dentition in an anatomically accurate model. METHODS A digital model containing the maxillary dentition, periodontal ligament, and surrounding bone was constructed from computerized tomography data. Virtual brackets were placed on 4 teeth (central and lateral incisors, canine, and first premolar), and a steel archwire (0.019 × 0.025 in) with a 0.5-mm step bend to intrude the lateral incisor was virtually inserted into the bracket slots. Forces applied to the dentition and surrounding structures were simulated by using the birth-death technique. RESULTS The goal of simulating a complete bracket-wire system on accurate anatomy including multiple teeth was achieved. Orthodontic forces delivered by the wire-bracket interaction were 19.1 N on the central incisor, 21.9 N on the lateral incisor, and 19.9 N on the canine. Loading the model with equivalent point forces showed a different stress distribution in the periodontal ligament. CONCLUSIONS The birth-death technique proved to be a useful biomechanical simulation method for placement of a continuous archwire in orthodontic brackets. The ability to view the stress distribution with proper anatomy and appliances advances our understanding of orthodontic biomechanics.

Patient response to sleep apnea screening in a dental practice

OBJECTIVE This study investigated patient response to a recommendation for physician evaluation following screening for obstructive sleep apnea (OSA) in a dental practice. METHODS In a community-based dental practice in Raleigh, North Carolina, 119 patients were recruited by nonprobability purposive sampling and administered both a validated subjective (STOP questionnaire) and objective (pulse oximeter) screening instrument for OSA. Patients who screened high-risk for OSA on either instrument were recommended to consult their physician within three months. All patients were contacted via telephone after three months to determine if they had consulted a physician regarding their screening results. Multivariate log-binomial models estimated prevalence ratios (PR) and 95 percent confidence limits (95% CL) for physician consultation according to OSA risk, adjusting for potential confounders. RESULTS Overall, 18.5 percent of patients screened high-risk on the STOP questionnaire alone, 26.1 percent on pulse oximetry alone, and 31.9 percent on both instruments. Follow-up of 111 subjects (93.3%) found that 40 (47.1%) of those high-risk for OSA on one or both instruments sought physician evaluation. Patients who screened high-risk on pulse oximetry were 2.55 times as likely to seek physician evaluation compared with those who screened low-risk on both instruments (PR = 2.55, 95% CL: 1.02, 6.37). Screening high-risk on the STOP questionnaire did not significantly increase the likelihood of physician evaluation. CONCLUSIONS Nearly, half of dental patients who screen high-risk for OSA may be responsive to a recommendation to seek physician evaluation.

Sleep Medicine Education in US and Canadian Dental Schools: A Report of the Inaugural Dental Educators Conference at the University of North Carolina School of Dentistry

The University of North Carolina School of Dentistry hosted the first ever national dental educators conference to gain an understanding of the current status of sleep medicine education in US and Canadian dental schools. “Sleep Disordered Breathing in Dental School Education: Past, Present, and Future” took place in Chapel Hill, NC, on August 24-25, 2013, and was partially supported by the American Academy of Dental Sleep Medicine, the Dean of the University of North Carolina School of Dentistry, and the Dental Foundation of North Carolina. Commercial vendors with an interest in sleep medicine provided support via educational grants or exhibitor fees.