Praphasri Rirattanapong

Effect of the topical application of 50% lignocaine hydrochloride on the sensitivity of dentine in man

OBJECTIVE To determine the effect of topical applications of 50% (w/v) lignocaine HCl on the sensitivity of human dentine. DESIGN The experiments were carried out on 12 premolars scheduled for extraction as part of orthodontic treatment in nine subjects (ages: 16-29 years). Dentine was exposed by cutting a cavity at the tip of the buccal cusp of each tooth, and etched with 35% phosphoric acid. The sensitivity of the exposed dentine to probing and air-blast stimuli was assessed before and after applying either 50% (w/v) lignocaine HCl solution or distilled water to the exposed dentine for 10min. Changes in the sensitivity of the dentine were monitored for up to 160min. The subject indicated the intensity of any pain produced by marking a 100mm visual analogue scale (VAS). RESULTS Before treatment, both forms of stimulus evoked pain in all the teeth. The median VAS score with probing was 40mm and, with air-blast stimulation, 30mm. 50% lignocaine HCl produced a progressive fall in these scores and after 30min there was no response to either probing or air-blast stimulation. The responses started to return 30-160min after the lignocaine had been washed off. Water had no effect. CONCLUSIONS Lignocaine will diffuse into exposed dentine and block the pain evoked by probing and air-blast stimuli provided that a sufficiently steep diffusion gradient is created. A topical application of a 50% (w/v) solution of lignocaine HCl for 10min will anaesthetise dentine within 30min.

Effects of the iontophoresis of lignocaine with epinephrine into exposed dentine on the sensitivity of the dentine in man

OBJECTIVE To determine the effects of the iontophoretic application of lignocaine and epinephrine to exposed dentine on the sensitivity of the dentine in human subjects. DESIGN The experiments were carried out on 13 healthy premolars (13 subjects) that were scheduled for extraction. Dentine was exposed at the tip of the buccal cusp by cutting a cavity which was etched with 35% phosphoric acid. The sensitivity of the dentine was tested with probing and air blast stimuli. The subject indicated the intensity of any pain produced with a score of 0-100. In 7 teeth, the cavity was filled with a solution containing 20% (w/v) lignocaine HCl and 0.1% (w/v) epinephrine HCl, and an iontophoretic current of 120 μA was passed for 90s. The sensitivity of the dentine was tested before and immediately after the treatment and then at 10 min. intervals for 40 min. Pulpal blood flow was recorded at each stage. Control experiments were carried out on 6 teeth using a solution containing only the epinephrine. RESULTS The lignocaine plus epinephrine solution completely blocked the pain produced by both forms of stimulus immediately, and this continued for at least 40 min. It also produced an immediate fall in pulpal blood flow that also lasted for at least 40 min. The epinephrine solution had the same effect on pulpal blood flow but no effect on dentine sensitivity. CONCLUSIONS The topical application of 20% lignocaine and 0.1% epinephrine, with an iontophoretic current of 120μA for 90s, will anaesthetize exposed, normal, dentine.

The iontophoresis of lignocaine with epinephrine into carious dentine for pain control during cavity preparation in human molars.

OBJECTIVE To determine the effectiveness of the iontophoretic delivery of lignocaine with epinephrine through carious dentine for pain control during cavity preparation. DESIGN The experiments were carried out on 56 carious molars that required class I restorations in 42 subjects (aged 15-20 years). The overhanging enamel and soft caries were removed then the sensitivity of the exposed dentine was tested with drilling, probing and air blast stimuli. The subject indicated the intensity of any pain produced by marking a visual analogue scale (VAS). The cavity was then filled with 20% w/v lidocaine with 0.1% w/v epinephrine and a 200 μA iontophoretic current applied for 2 min after which the sensitivity of the dentine was re-tested. If the dentine was not anaesthetized, the treatment and testing were repeated up to 6 times. RESULTS The total duration (min) of iontophoresis required to anaesthetize the dentine was: 2 in 7 teeth, 4 in 17 teeth, 6 in 14 teeth, 8 in 4 teeth, and 10 in 7 teeth. The remaining 7 teeth were not anaesthetized even after 14 min of iontophoresis. CONCLUSIONS The iontophoretic delivery of lignocaine with epinephrine anaesthetized dentine for cavity preparation in 49 of 56 (87.5%) of carious molars.

Preschool children's caregivers' attitudes and behavior regarding bottle feeding in Bangpakong, Chachoengsao.

Objectives: To study a group of preschool childrens caregivers’ attitudes and behavior regarding bottle feeding in Bangpakong, Chachoengsao. Materials and Methods: The study sample comprised 320 caregivers of preschool children aged 3–6 years, who were attending the public preschools in Bangpakong, Chachoengsao, and they completed self-administered questionnaires. The questionnaires had information about demographic data, weaning status, the feeding practices for children who were still on a bottle, and the caregivers’ attitudes on bottle feeding according to weaning status. Results: Of these children, 38.4% were still on a bottle while 61.6% had been weaned. Mean age at the weaning time was 3.1 ± 0.6 years. The most common reason that led caregivers of bottle feeding group to allow continuation of the habit was the child refused to wean. Of these caregivers, 56% lacked knowledge concerning the appropriate weaning time and that the use of bottles should be actively discouraged for children after 1 year of age. Attitudes between bottle feeding and weaned groups were significantly different (P < 0.05) in the following: a child should be introduced to drink from cup after 1 year of age, nursing bottle works best to stop a child from crying, early weaning results in poor mental health, and early weaning results in malnutrition. Conclusion: Prolonged bottle feeding beyond the recommended age was found in the majority of preschool children in this study. Dental professions should provide oral health promotion education program including feeding practice information to caregivers.

The efficiency of child formula dentifrices containing different calcium and phosphate compounds on artificial enamel caries.

Objectives: Fluoride toothpaste has been extensively used to prevent dental caries. However, the risk of fluorosis is concerning, especially in young children. Calcium phosphate has been an effective remineralizing agent and is present in commercial dental products, with no risk of fluorosis to users. This in vitro study aimed to compare the effects of different calcium phosphate compounds and fluoride-containing dentifrices on artificial caries in primary teeth. Materials and Methods: Fifty sound primary incisors were coated with nail varnish, leaving two 1 mm2 windows on the labial surface before immersion in demineralizing solution for 96 hours to produce artificial enamel lesions. Subsequently, one window from each tooth was coated with nail varnish, and all 50 teeth were divided into five groups (n = 10); group A – deionized water; group B – casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) paste (Tooth Mousse); group C – 500 ppm F (Colgate Spiderman®); group D – nonfluoridated toothpaste with triple calcium phosphate (Pureen®); and group E – tricalcium phosphate (TCP). Polarized light microscopy and Image-Pro® Plus software were used to evaluate lesions. Results: After a 7-day pH-cycle, mean lesion depths in groups A, B, C, D, and E had increased by 57.52 ± 10.66%, 33.28 ± 10.16%, 17.04 ± 4.76%, 32.51 ± 8.99%, and 21.76 ± 8.15%, respectively. All data were processed by the Statistical Package for the Social Sciences (version 16.0) software package. Comparison of percentage changes using one-way analysis of variance and Fishers least squares difference tests at a 95% level of confidence demonstrated that group A was significantly different from the other groups (P < 0.001). Lesions in groups B and D had a significant lesion progression when compared with groups C and E. Conclusions: All toothpastes in this study had the potential to delay the demineralization progression of artificial enamel caries in primary teeth. The fluoride 500 ppm and TCP toothpastes were equal in the deceleration of enamel caries progression and better than CPP–ACP paste and TCP toothpaste.