Aim:The aim of this study was to compare dentoskeletal effects and patient's satisfaction with a modified twin-block (clear twinblock) and classic twin-block.
Materials and methods:A total of 62 patients with skeletal class II malocclusion contributing to mandibular retrognathism with a minimum of 4 mm overjet, the FMA angle between 20 to 25 degree and being in stage 2 to 3 of cervical vertebral maturation participated in this study. Subjects were randomized in 1:1 ratio to classic and clear twin-block. Lateral cephalograms were taken at two stages-Pre-and post-treatment (when the overjet reduced to 1 to 0 mm). All the measurements were done with Dolphin software version 10.5. Four months after the start of the treatment the patients were asked to fill the questioners regarding their compliance from the appliances.Results: Both classic and clear twin -block groups showed mandibular advancement without statistically significant difference between them. However, SNB angle increased slightly more in clear group than the classic one.'' Headgear effect'' is not statistically noticeable in both groups. However, SNA angle decreased slightly more in Classic group. Increased in lower incisors proclination was happening in both groups, but in a clear group, this increase was significantly less. Overbite reduction could be seen in both groups with significantly more reduction in the classic group.
Conclusion:Increase in lower incisors proclination was less in clear group than the classic one. Overbite reduction was more in the classic group than the classic one.Clinical significance: Clear twin-block is more beneficial in skeletal class II patients with proclined lower incisors and vertical growth pattern.
The current study aimed to investigate the effect of biocompatible kinds of toothpastes containing natural ingredients such as theobromine and caffeine on the enamel microhardness after demineralization. 72 maxillary premolar teeth extracted for orthodontic purposes were used in this study. Primary enamel surface microhardness examinations were performed using a Digital Micro Vickers Hardness Tester following the Knoop technique (50 g load for 15 s with three indentations at various points). The specimens were immersed in lactic acid (pH = 5.4) for 7 days, washed with distilled water, dried, and then retested for microhardness. According to the type of toothpaste used for brushing, all specimens were categorized as follows: Group 1, Theodent classic® toothpaste (theobromine); Group 2, Power Energy toothpaste (caffeine); Group 3, Colgate toothpaste (fluoride); and Group 4, distilled water as the negative control. The specimens were retested for enamel microhardness after brushing 2 times a day for one month. After brushing with different types of toothpaste, for all experiment groups, the increase in microhardness values in the demineralized enamel surfaces was significant and there were significant differences between them (
p
value <0.05). The fluoride group had the highest microhardness and had a significant difference with the caffeine and distilled water groups, but there was no significant difference with the theobromine group (
p
value <0.05). In the theobromine group, the hardness was considerably higher than in the caffeine and distilled water groups. There was no significant difference between the caffeine and distilled water groups. Theobromine toothpaste had the same remineralization effect as that of fluoride toothpaste, while caffeine toothpaste had no positive effect on the remineralization process.
Background: Brackets' debonding without any damage to the teeth is very important. Objectives: The aim of this study was to compare the debonding characteristics of the metal conventional and self-ligating brackets. Patients and Methods: 69 maxillary premolars were randomly assigned in 3 groups. Metal brackets of Damon, In Ovation and conventional systems were bonded to the teeth. The brackets were debonded with debonding pliers. Debonding strengths, adhesive remnant index, and enamel damage were evaluated. A Zwick model universal testing machine was used to measure debonding strengths. The debonding strength values were statistically analyzed by one-sided analysis of variance while the increase in the enamel crack numbers and length and the remained adhesive index were analyzed by chi-square test. Results: The means of the debonding strength in the brackets of in ovation, damon and conventional systems were 15.22, 11.4 and 8.67 MPa respectively. Significant differences were observed regarding debonding strength between three types of brackets (all: P < 0.001). After debonding of in ovation, damon and stainless steel brackets; the increased numbers of the enamel cracks were noted in 26.06%, 21.74% and 17.39% cases respectively. Also, the increased cracks lengths were demonstrated in 47.83%, 39.13%, and 30.43% cases. No significant differences were observed regarding the increase of the enamel cracks number and length and the amounts of residual adhesive on the teeth. Conclusions: The debonding characteristics of the metal self-ligating were comparable to the conventional brackets.
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