Increasing the number of inter-arch contacts improves mastication in adults with Down syndrome: a prospective controlled trial.

Feeding difficulties due to their condition have been widely described for babies, children and adults with Down syndrome (DS). A previous study demonstrated that, compared with wearing a placebo appliance, wearing an occlusal appliance increased inter-arch dental contacts, improved the oral health status of adults with DS and normalised their mandibular rest position. This longitudinal prospective controlled trial aimed to evaluate whether increasing inter-arch contacts in adults with DS would lead to improved masticatory efficiency. Fourteen subjects with DS (mean age±SD: 28.5±9.3years) and twelve controls without DS (24.6±1.0years) were video recorded while chewing samples of carrot and peanuts with and without an oral appliance that was designed to equalise the number of posterior functional units (PFUs) in both groups. Three parameters were collected during mastication for 15cycles and until swallowing: food refusals, food bolus granulometry (D50) and kinematic parameters of the chewing process (number of cycles, chewing duration and cycle frequency within the chewing sequence). In the DS group, increasing the number of PFUs led to a decrease in bolus particle size, to fewer masticatory cycles needed to produce a bolus ready for swallowing and to a decrease in the occurrence of food refusal, while mean chewing frequency did not vary. In the control group, bolus granulometry and chewing time increased with appliance wear while mean chewing frequency decreased. These changes clearly indicate a functional improvement in subjects with DS. This study also demonstrated a causal relationship between the number of functional pairs of posterior teeth and improved mastication. Any evaluation of feeding behaviour in persons with DS should consider inter-arch dental contacts as an explicative variable for feeding problems and their nutritional and respiratory consequences.

Effect of occlusal appliance wear on chewing in persons with Down syndrome.

The effects of Down syndrome (DS) include orofacial dysmorphology with neuro-motor difficulties and inter-maxillary discrepancy. It is unclear whether improving the inter-arch relationship would suffice to overcome feeding difficulties in persons with DS. This randomized, double-blind, placebo-controlled crossover study is a first step in evaluating the impact of wearing an orthetic intra-oral appliance on chewing variables in 8 subjects with DS (4 males and 4 females; mean age: 27.6+/-6.1 years). The primary chewing variables were measured through video and electromyographic (EMG) recordings. Secondary variables were (i) modifications in oral health status using the oral assessment for Down syndrome (OADS) questionnaire, (ii) number of inter-arch contacting units (ICUs), (iii) subjects' compliance in wearing the appliance and (iv) subjects' preference between placebo and occlusal appliances. The simultaneous use of EMG and video recordings revealed the presence of lower jaw movements not corresponding to EMG activities in the masticatory muscles. Compared with the pre-treatment situation, wearing an occlusal appliance decreased chewing frequency and increased masticatory time. It is not known whether these changes were indicative of an improvement or a worsening of masticatory function. Persons with DS did not fully adapt to changes in food hardness. A large inter-subject variability was noted, but pre-treatment individual values were not predictive of appliance effect. The maintenance of the number of ICUs obtained at the first installation of appliance and the responses to OADS and satisfaction questionnaires suggested that patients felt more comfortable and that jaw and tongue protrusion were reduced with the appliance.

Modification of behavior with 50% nitrous oxide/oxygen conscious sedation over repeated visits for dental treatment a 3-year prospective study.

In various medical domains, inhalation of nitrous oxide (N2O) in oxygen (O2) is indicated to alleviate pain and anxiety during routine treatment. Repeat treatment may often be indicated. Little data are available, however, to evaluate the long-term efficacy and side effects of reiterated N2O/O2 sedation. The aim of this study was to compare behavior during dental treatment under a premix of 50% N2O/O2 between first experience and repeat experiences of sedation in a cohort of uncooperative patients. Five hundred forty-three patients (age range, 1-94 years; mean, 17 +/- 16 years) experiencing conscious sedation for dental treatment for the first time were recruited at a special care unit during 3 years. A modified Venham scale was used to evaluate patient behavior at 5 steps during each session. Completion of planned treatment and occurrence of adverse side effects of sedation were additional criteria. Patients experienced sedation for the first time for 378 sessions, and the session was a repeat experience in 843 cases (number of visits: range, 1-6). Patient cooperation significantly improved during visits at first contact with the dentist and when applying the mask (P < 0.0001, between sessions 1 and 2). Between the first and the third sessions, the percentage of very uncooperative patients decreased from 23% to 3.7% at first contact with the dentist and from 22.3% to 8.5% on application of the mask. Experience of reiterated dental treatment under sedation with 50% N2O/O2 premix helps uncooperative patients to cope with dental treatment in the long term.