Residents’ journal review

Light-curable fluoride varnish may be effective in preventing enamel demineralization during orthodontic treatment for up to 4 months

Mehta A, Paramshivam G, Chugh VK, Singh S, Halkai S, Kumar S. Effect of light-curable fluoride varnish on enamel demineralization adjacent to orthodontic brackets: an in-vivo study. Am J Orthod Dentofacial Orthop 2015;148:814-20

Enamel demineralization due to plaque retention around fixed orthodontic appliances is a challenge that can be appreciated by most orthodontists. The authors of this in-vivo longitudinal study investigated the effectiveness of a particular light-curable fluoride varnish, Clinpro XT, in meeting this challenge. The study included 38 patients who were planned for first premolar extractions (152 teeth) as part of their orthodontic treatment. In each subject, 2 first premolars were treated with the fluoride varnish, and the other 2 remained untreated as the control group. The premolars of the opposite side and opposite arch received the same treatment; eg, if the maxillary right and mandibular left first premolars received fluoride varnish, the maxillary left and mandibular right first premolars were untreated. At intervals of 15 (n = 30), 30 (n = 30), 45 (n = 30), 90 (n = 18), and 120 (n = 18) days, the first premolars were extracted and examined to measure the depth of enamel demineralization. The extracted teeth were examined under polarized light microscopy after being sectioned and photographed at 25-times magnification. In each group, 63 teeth were evaluated. The results for the control group (no varnish) showed enamel demineralization starting at 30 days, with the lesions progressing deeper at each subsequent interval. In the treatment group, no demineralization lesions were detected, with the exception of 3 teeth. The results indicate that enamel demineralization can occur with orthodontic brackets as seen with the control group. The results also showed that application of Clinpro XT light-curable fluoride varnish may be effective in preventing enamel demineralization for up to 4 months as shown in the treatment group. One factor to consider when reviewing this study is that the subjects were instructed to maintain acceptable hygiene at home and to use nonfluoride toothpaste. Lack of adherence to these instructions can influence the results. The authors briefly discussed the significance of in-office fluoride applications, pointing out that the beneficial effects of fluoride to prevent demineralization are well established, yet many delivery regimens are the take-home variety. Take-home applications can be effective but are subject to noncompliance. An effective in-office application of fluoride addresses the issue of noncompliance, and the results of the study suggest that light-curable fluoride varnish may be considered viable because of its efficacy over a 4-month period. The long-term efficacy for the duration of orthodontic treatment is yet to be investigated.

Reviewed by Pamela Ortiz

Longitudinal changes in molar relationships during the mixed dentition

Barros SE, Chiqueto K, Janson G, Ferreira E. Factors influencing molar relationship behavior in the mixed dentition. Am J Orthod Dentofacial Orthop 2015;148:782-92

It is known that the initial deciduous molar relationship plays a role in the future permanent molar relationship. The authors of this retrospective cohort longitudinal study evaluated different patterns of molar relationship changes, which were longitudinally followed from the mixed to the permanent dentition. The difference between this study and previous studies was that dental and skeletal features were evaluated together. Dental casts and cephalograms were analyzed at 2 times: early mixed dentition (T1) with all permanent incisors and first molars erupted, with deciduous molars and canines; and the final permanent dentition (T2) with all permanent teeth up to the second molars. Various dental and skeletal measurements were included that might significantly contribute to molar relationship changes in different ways from the mixed to the permanent dentition. The molar relationship changed on average by 1 mm toward Class I in the total sample. Ninety-four percent of mesial steps at T1 remained Class I molar relationships at T2. Eighty-five percent of distal steps remained Class II molar relationship at T2. The overall probability of keeping the same occlusal status was high for these groups. When subjects had a flush terminal plane at T1, 57% of flush terminal planes changed to a Class I molar relationship, and 43% changed to a Class II molar relationship at T2. Subjects with a flush terminal plane and a narrow maxillary arch and mandibular retrusion seemed to be more prone to keeping their transverse and skeletal discrepancies beyond the mixed dentition. Orthodontists should continually evaluate patients with a flush terminal plane because self-correction should not be expected. The diagnosis of unfavorable terminal plane relationships should be established early to avoid undertreatment or overtreatment.

Reviewed by Brik Nielsen

Longitudinal changes in molar relationships during the mixed dentition

Barros SE, Chiqueto K, Janson G, Ferreira E. Factors influencing molar relationship behavior in the mixed dentition. Am J Orthod Dentofacial Orthop 2015;148:782-92

It is known that the initial deciduous molar relationship plays a role in the future permanent molar relationship. The authors of this retrospective cohort longitudinal study evaluated different patterns of molar relationship changes, which were longitudinally followed from the mixed to the permanent dentition. The difference between this study and previous studies was that dental and skeletal features were evaluated together. Dental casts and cephalograms were analyzed at 2 times: early mixed dentition (T1) with all permanent incisors and first molars erupted, with deciduous molars and canines; and the final permanent dentition (T2) with all permanent teeth up to the second molars. Various dental and skeletal measurements were included that might significantly contribute to molar relationship changes in different ways from the mixed to the permanent dentition. The molar relationship changed on average by 1 mm toward Class I in the total sample. Ninety-four percent of mesial steps at T1 remained Class I molar relationships at T2. Eighty-five percent of distal steps remained Class II molar relationship at T2. The overall probability of keeping the same occlusal status was high for these groups. When subjects had a flush terminal plane at T1, 57% of flush terminal planes changed to a Class I molar relationship, and 43% changed to a Class II molar relationship at T2. Subjects with a flush terminal plane and a narrow maxillary arch and mandibular retrusion seemed to be more prone to keeping their transverse and skeletal discrepancies beyond the mixed dentition. Orthodontists should continually evaluate patients with a flush terminal plane because self-correction should not be expected. The diagnosis of unfavorable terminal plane relationships should be established early to avoid undertreatment or overtreatment.

Reviewed by Brik Nielsen

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Apr 4, 2017 | Posted by in Orthodontics | Comments Off on Residents’ journal review

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