Gajanan Kulkarni

Detection of interproximal demineralized lesions on human teeth in vitro using frequency-domain infrared photothermal radiometry and modulated luminescence

Frequency-domain photothermal radiometry (FD-PTR or PTR) is used to detect mechanical holes and demineralized enamel in the interproximal contact area of extracted human teeth. Thirty-four teeth are used in a series of experiments. Preliminary tests to detect mechanical holes created by dental burs and 37% phosphoric acid etching for 20 s on the interproximal contact points show distinct differences in the signal. Interproximal contact areas are demineralized by using a partially saturated acidic buffer system. Each sample pair is examined with PTR before and after micromachining or treating at sequential treatment periods spanning 6 h to 30 days. Dental bitewing radiographs showed no sign of demineralized lesion even for samples treated for 30 days. Microcomputer tomography (micro-CT), transverse microradiography (TMR), and scanning electron microscopy (SEM) analyses are performed. Although micro-CT and TMR measured mineral losses and lesion depths, only SEM surface images showed visible signs of treatment because of the minimal extent of the demineralization. However, the PTR amplitude increased by more than 300% after 80 h of treatment. Therefore, PTR is shown to have sufficient contrast for the detection of very early interproximal demineralized lesions. The technique further exhibits excellent signal reproducibility and consistent signal changes in the presence of interproximal demineralized lesions, attributes that could lead to PTR as a reliable probe to detect early interproximal demineralization lesions. Modulated luminescence is also measured simultaneously, but it shows a lower ability than PTR to detect these interproximal demineralized lesions.

An in vitro study of the torsional properties of new and used rotary nickel-titanium files in plastic blocks.

OBJECTIVE The purpose of this study was to compare torque (in grams per centimeter) and angle of rotation (in degrees) at the time of fracture of new and used nickel-titanium .04 ProFile rotary files. The relationship between the size of the instrument and the torque at fracture was also investigated. STUDY DESIGN The torque and angle of rotation at fracture of new and used nickel-titanium .04 ProFile rotary files Nos. 15 to 40 were determined according to American National Standards Institute/American Dental Association Specification No. 28. Analysis of variance was used to compare the torque and angle of rotation at fracture of the different sizes of the new instruments and of new and used instruments of the same size (alpha =.05). The relationship between torque at fracture and the size of the instrument was determined by means of regression analysis. RESULTS The torque at fracture of the new instruments increased significantly with the diameter. The used instruments, Nos. 25 to 40, had significantly lower values of torque at fracture than did the new ones. There were no statistically significant differences between the angle of rotation at fracture of the new and the used instruments (P >.05). A stronger relationship was found between the size of the file and the torque at fracture for the new instruments (P <.0001) than for the used ones (P <.0001). CONCLUSION The results of the present study suggest that the values of the torque at fracture of new instruments increased significantly with the diameter. The results also suggest that repeated use of ProFile .04 instruments mainly affected the torque at fracture.

Accuracy of the TCM Endo III Torque-Control Motor for Nickel-Titanium Rotary Instruments

The purpose of this study was to determine the torque output and examine the accuracy of five TCM Endo III torque control motors. A handpiece was attached to the motor and gripped with a vise. A 0.07 taper Orifice Shaper, size 50, was inserted in the handpiece. The instrument tip was clamped in a chuck connected to a torque sensor. Four torque settings were evaluated at 350 rpm. Ten tests were performed at each torque setting. A new instrument was used for each test. The means of the torque values generated by the motors at the different torque levels were analyzed using analysis of variance and post-hoc pairwise comparisons with the Bonferroni test. The actual torque values were significantly higher than the torque preset on the motor (p < 0.0001) and did not differ significantly among the motors (p > 0.05). The actual torque deviated from the preset torque. The usefulness of these motors is questionable.

Lack of Oral Care Policies in Toronto Daycares

OBJECTIVES Currently, there is a deficit of information on policies regarding oral hygiene practices in Toronto daycares. It is unknown if any tooth-brushing programs are in existence and if children are permitted to follow professional advice on oral hygiene. The main objectives of this investigation were to a) determine the prevalence of oral care policies in daycares and b) examine the availability of resources. METHODS Telephone interviews were conducted with daycare supervisors using a pretested questionnaire. Summary statistics and the chi-square test were used to analyze the results. RESULTS Two hundred forty-nine questionnaires were completed (response rate of 99.6 percent), representing 38 percent of the total daycare population (650) in Toronto. Eighty-three percent did not have a policy on oral care and 11 percent would not cede to requests from parents or medical professionals to brush teeth. However, 50 daycares indicated that their centers used to have a tooth-brushing program, and most (79 percent) were open to establishing an oral care policy. Fifteen percent reported not having proper sinks for tooth brushing. CONCLUSIONS Many daycares do not have a policy regarding oral hygiene. A policy that encourages and provides guidance on safe tooth-brushing procedures is needed and may improve the oral health of preschool children.

Oral Health Promotion in Infants and Children: Models and Long-Term Effectiveness

The concepts of anticipatory guidance, dental home, and the year one dental visit in the context of oral health in children are slowing permeating the dental community. The above principles are now taught in dental schools, especially at the graduate level in specialty pediatric dentistry programs. Various dental associations, societies, and advocacy bodies have adopted those principles and advocate for them to varying degrees. While the value of oral health promotion in infants and young children is widely recognized, there is a diversity of approaches to the same. To date, a comprehensive overview of the various models, best practices, or the benchmarks for assessing their effectiveness has not been undertaken. In this special issue, dental and nondental clinicians, health promoters, and investigators have contributed to original research articles as well as proposals that document practices, experiences, and evaluation of outcomes related to oral health promotion in infants and young children from around the world. Some of the articles document the long-term effectiveness of their oral health promotion activities or models with clearly identifiable clinical outcomes. The issue highlights several facts. There is a diversity of approaches employed by a diversity of professionals. The goals, methodology, and outcome measures vary greatly. For example, the ages of the children at which these efforts ought to be directed vary. The scope of the oral health promotion activities ranges from simply providing education to parents and caregivers to provision of preventive services such as the application of fluoride varnishes. Another issue that comes to light is whether health promotion activities should primarily be aimed at caries prevention or if they should provide comprehensive anticipatory guidance which includes education on matters such as prevention of malocclusions in children due to habits, prevention of trauma, and avoidance of other risk behaviors that can predispose children to oral problems. With the advent of newer digital technologies and platforms for dissemination of information, the scope and reach of such activities are bound to evolve. Teledentistry should allow for well-established programs with documented clinical effectiveness to reach parts of the world where childhood oral disease is endemic and access to care is still an issue. There is a need for the development of oral health promotion models deliverable through modern technologies. There is great paucity of the literature documenting the effectiveness of such programs, both in the short and especially the long term. Moreover, the relationship between oral health in infancy and that in adulthood has yet to be systematically explored. While it is reasonable to conjecture that the establishment of risk factors very early in life might have long-lasting and indeed life-long effects, this has not been explored and documented. Without such evidence it would be difficult to convince governmental or non-governmental agencies to fund such programs and educational institutions to undertake training of health promoters. This special journal issue is a starting point for developing a consensus around this important pediatric health topic. Gajanan Kulkarni