Journal of Dental Medicine

Background and Aims: The first permanent molar is susceptible to caries, endodontic complications and developmental anomalies. Compromised teeth with poor prognosis could cause the clinician to face dilemmas. The aim of this review article was to assess recent guidelines on the treatment planning of compromised first permanent molars in mixed dentition period.

Materials and Methods: The design of the study was based on review of literature by searching the MEDLINE, Web of science and Google scholar. Key words (permanent first molar, extraction, treatment plan) were used. This search was limited to the English articles published after the year 2000.

Conclusion: A number of factors influenced decision-making process regarding compromised first permanent molars including the restorative status of the tooth, dental age of the patient, degree of crowding and occlusal relationships were assessed. The ideal time for removal of these teeth was 8-9 years of age. However, the current evidence for managing compromised first permanent molars demands clinical trials.

Background and Aims: Functional therapy locates the mandible in a more anterior and inferior position. Tongue posture and oropharynx space have a considerable relationship with mandibular posture. The aim of the present study was to determine the changes of tongue posture and oropharynx space following treatment with Twin block appliance in adolescent patients with class II division 1 ma1occlusion.
Materials and Methods: Twenty two patients (14 girls mean age:11.5, 8 boys mean age:12.5 years) who were treated with twin-block appliance were enrolled. Cephalograms were used to assess the linear measurements. Graber pattern and McNamara parameter were used to evaluate the tongue posture and oropharynx space, respectively. Data analysis was performed by paired t-test.
Results: The findings of the present study showed a significant increase in anterior position of tongue (P=0.06). Oropharynx space was increased significantly (P<0.001). There was a significant correlation between the decrease of ANB and anteroposterior increase of oropharynx space.
Conclusion: Twin-block appliance caused considerable forward movement of tongue and significant increase of oropharynx space in the sagittal plan.

Background and Aims: The purpose of this study was to investigate the application of nanoparticles in orthodontics.
Materials and Methods: This study was conducted using a review method by searching Scopous, Google Scholar and Web of science. Key words (Nano silver, Nano ZnO, Nano Chitosan, Nano Curcumin and Nanoparticles) were used. These searches were limited to the English ariticles after the year 2010.
Conclusion: According to the published studies, silver nanoparticles, curcumin, titanium oxide, chitosan, zinc oxide, quaternary ammonium derivatives exhibit appropriate antibacterial properties. Further studies are recommended to investigate the effect of each of these nanoparticles on the bond strength. In order to reduce the decay, there is lack of evidences regarding the addition of ACP nanoparticles and nanoparticles of calcium- phosphate and fluoride. Therefore, further studies are recommended. Studies have shown that the addition of zinc oxide nanoparticles to orthodontic wires could reduce the friction between the wire and the bracket. While, adding titanium oxide nanoparticles to bracket increased the friction. Although, evidences in this regard are inadequate but it seems that nanoparticulates are less toxic than conventional materials.aa