Primosch Re

Influence of Operatory Size and Nitrous Oxide Concentration Upon Scavenger Effectiveness

Concern regarding environmental health hazards for dental personnel chronically exposed to waste nitrous oxide (N2O) prompted this investigation. The influence on ambient N 2O levels of scavenging, operatory size, and N2O concentration delivered to the patient was evaluated during treatment of 36 pediatric dental patients. The results showed that scavenging significantly reduced ambient N2O levels measured at 50-56 cm from the patients nose. Scavenged ambient N2O levels were also observed to decrease when N2O concentrations administered to the patient were reduced from 50 to 30%. This concentration effect was not observed in the non-scavenged groups. ANOVA showed that operatory size exerted a non-significant influence on ambient N2O. The data collected during routine treatment of pediatric dental patients demonstrated that the scavenging system tested significantly reduced waste N20 in the operators breathing zone, nearly approximating the 25-ppm recommendation established by the National Institute for Occupational Safety and Health (NIOSH).

Oral Arginine Metabolism May Decrease the Risk for Dental Caries in Children

Arginine metabolism by oral bacteria via the arginine deiminase system (ADS) increases the local pH, which can neutralize the effects of acidification from sugar metabolism and reduce the cariogenicity of oral biofilms. To explore the relationship between oral arginine metabolism and dental caries experience in children, we measured ADS activity in oral samples from 100 children and correlated it with their caries status and type of dentition. Supragingival dental plaque was collected from tooth surfaces that were caries-lesion-free (PF) and from dentinal (PD) and enamel (PE) caries lesions. Regardless of children’s caries status or type of dentition, PF (378.6) had significantly higher ADS activity compared with PD (208.4; p < .001) and PE (194.8; p = .005). There was no significant difference in the salivary arginolytic activity among children with different caries status. Mixed-model analysis showed that plaque caries status is significantly associated with ADS activity despite children’s age, caries status, and dentition (p < .001), with healthy plaque predicting higher ADS activity compared with diseased plaque. Plaque arginine metabolism varies greatly among children and tooth sites, which may affect their susceptibility to caries.

Oral characteristics of children with attention-deficit hyperactivity disorder.

The purpose of this study was to compare the oral and demographic characteristics of children with attention-deficit hyperactivity disorder (ADHD) to those of a control group of children. A sample of 25 dental records of children medicated for ADHD was compared to 127 records of healthy children not receiving any medication. The children with ADHD had a statistically higher prevalence of toothache, bruxism, bleeding gums, and oral trauma histories than the control group (chi square, p < 0.05). The differences in other recorded oral characteristics and habits, such as plaque accumulation, gingival inflammation, calculus, oral hygiene compliance, dental caries experience, and unmet dental needs, were not statistically significant. The demographic characteristics such as age, gender, residence, ethnicity, income, and payment method were also not significantly different between the two groups. There is a need to develop and implement specific strategies for the early prevention and treatment of oral diseases in children with ADHD.

Distribution and Retention of Salivary Fluoride from a Sodium Fluoride Tablet Following Various Intra-oral Dissolution Methods

The distribution and retention of salivary fluoride were investigated according to the following intra-oral dissolution methods of a sodium fluoride tablet: active chewing/swishing, active sucking/swishing, and passive dissolution in the maxillary and mandibular labial vestibule. The results suggested that the oral cavity was somewhat compartmentalized, in that homogeneous distribution of a dissolved fluoride tablet did not occur throughout the mouth, but rather each site sampled was influenced by various rates of clearance and retention. Tablet chewing may have an advantage over tablet sucking in terms of salivary fluoride retention, and there was a tendency for fluoride to be preferentially retained in the maxillary labial vestibule following swishing. The passive tablet dissolution methods resulted in a less homogeneous distribution of fluoride. Although the fluoride retention values for passive dissolution were impressively superior to either active dissolution method, the alarmingly high salivary fluoride concentrations (4000 ppm F) recorded at the passive dissolution sites should discourage its use until the potential cytotoxicity of this approach is thoroughly investigated.

Operatory Ventilation and Scavenger Evacuation Rate Influence on Ambient Nitrous Oxide Levels

Investigations have shown that greater than Federally-recommended levels of ambient nitrous oxide often exist in the dental workplace. The purposes of this investigation were to examine the influences of (1) operatory ventilation rate and (2) scavenger evacuation rate on ambient nitrous oxide concentrations within a closed dental operatory. This laboratory investigation utilized a scavenging nasal mask assembly (Porter/Brown) to deliver 40% nitrous oxide in oxygen, at a total flow rate of 5 L/min, to a mannequin positioned supinely in a dental chair. Eight experimental groups were assigned based on combinations of operatory air exchange rates (0, 5, 10, or 15 room air changes per hour) and scavenger evacuation rates (18.8 L/min and 21.4 L/min). Ambient nitrous oxide levels were monitored at four locations (0, 15.3, 30.7, and 61.4 cm) from the nasal mask by means of an infrared spectrophotometer (Miran 1B). The operatory air exchange rate was measured with a flow hood (Short Ridge) and manipulated to one of the desired ventilation rates. Time-weighted average (TWA) concentrations of ambient nitrous oxide (ppm) were continuously recorded at 15-second intervals with a microprocessor (DL332F Datalogger) connected directly to a microcomputer. The results demonstrated that significantly reduced (p < 0.05) ambient nitrous oxide levels were achieved with increasing room air exchange rates and the high scavenger evacuation rate. It was concluded that operatory ventilation and scavenger evacuation rates were significant control measures available for reduction of ambient nitrous oxide to Federally recommended levels.