Abstract-Tooth extraction to overcome the functional and aesthetic outcomes has become an issue in orthodontic treatment. Tooth size discrepancy was determined through a Bolton analysis. Overall Bolton ratio has changed after the tooth extraction, and affected by different extraction. The aim is to determine the effect of premolar extraction to overall Bolton ratio in Class II malocclusion. Subject was 40 patients with Class II malocclusion in accordance with the inclusion criteria. Measurements performed directly on 12 maxillary and mandibular teeth using an electronic digital caliper. The initial overall Bolton ratio was calculated on the whole samples and continued with several hypothetical extractions. After that, the calculation of the overall Bolton ratio after hypothetical extractions were done and the results were statistically tested to see the effect of the premolar extraction on overall Bolton ratio in Class II malocclusion. The initial overall Bolton ratio consisted of small overall Bolton ratio (86.27±3.19) the number of 7 subjects (17.5%), normal overall Bolton ratio (91.63±1.19) with the number of 23 subjects (57,5% ) and large overall Bolton ratio (95.65± 2.47) with the number of 10 subjects (25%). Wilcoxon test showed the effect of premolar tooth extractions on overall Bolton ratio in Class II malocclusion (p=0.001). Overall Bolton ratio shifted significantly into the normal Bolton ratio were observed in the combination of maxillary first premolar and mandibular second premolar extractions, while the maxillary first premolar extraction increased the overall Bolton ratio. Premolar tooth extraction affects the overall Bolton ratio in Class II malocclusion.

BACKGROUNDAdding a binder to improve the mechanical properties of heat polymerised polymethylmethacrylate such as its transverse strength is now being developed. One of them is by adding high molecular nanochitosan. This study aims to determine the effect of adding high molecular nanochitosan on transverse strength of heat polymerised polymethylmethacrylate denture base resin.

Background: The addition of other ingredients to maintain color stability of heat polymerized polymethylmethacrylate is being developed. One of them is by adding high molecular nano chitosan. Purpose: This study aimed to determine the color stability of heat polymerized polymethyl methacrylate denture base resin after an addition of high molecular nano chitosan. Method: 30 sample pieces of acrylic plate (40x10x2 mm) were divied into 6 groups: control group and groups with the addition of chitosan nano gel percentages of 0.25, 0.50, 0.75, 1.0 and 1.50%. 2 ml chitosan nano gel was added into the mixture of acrylic resin with 23 g : 10 ml (P : L). After the mixture was inserted into a mold and then pressed and cured at 74oC for 120 minutes and then 100o C for 60 minutes. Acrylic plates were then released from the mold and finished. Color stability of acrylic resin were measured using UV-Vis Spectrophotometer and analyzed with a one way Anova. Result: The results showed significant differences in color stability after the addition of high molecular nano chitosan. The best color stability found in 1.0% the addition of chitosan nano gel group, the value was 0.07589 cm-1. Conclusion: The chitosan nano gel can be used to maintain color stability of heat polymerized polymethyl methacrylate denture base resin.

Background: Copper (Cu), nickel (Ni), chromium (Cr) ion release, and surface topography change from the orthodontic wire are the initial processes of corrosion that may affect the mechanical properties of the archwire.  In this study, we aim to evaluate the effect of CHX, NaF, and chitosan on the corrosion of  CuNiTi wire nickel and copper ions released, surface roughness change, and archwire deflection. Methods: Ninety samples of CuNiTi Tanzo™ archwires were divided into five groups according to their immersion solution: Artificial Saliva, CHX, NaF, CHX-NaF, and chitosan group. Each group was further divided into three subgroups (n=6) corresponding immersion time, i.e., two, four, and six weeks. The corrosion of the samples was analyzed with an atomic absorption spectrophotometer (AAS), scanning electron microscope (SEM), and universal testing machine (UTM). Results: The amount of nickel ion releases was increasing, but the copper ion releases were reduced by the time of observations. The highest nickel ion was released in the CHX-NaF group and the lowest in the chitosan group for six-week immersion. It also corresponded to the surface topography by SEM analysis which showed the most extended cracks and deep pits in the CHX-NaF group and a smoother surface in the chitosan group. Copper ion release showed the highest ion release in the NaF group and the lowest release in the chitosan group. The unloading force of CuNiTi archwire deflection remains the same at week two and week four for all mouthwashes. Conclusion: The use of mouthwashes that contained CHX, NaF, and chitosan could further alter the passive layer and cause higher nickel and copper ion release and increased CuNiTi archwire surface structure porosity. But there is no distinction between mouthwashes to release the unloading force within two until four weeks.

Pengunaan produk-produk alam di bidang kedokteran saat ini semakin berkembang pesat. Salah satu bahan alami yangdigunakan adalah kitosan. Tujuan penulisan ini adalah untuk menjelaskan kegunaan kitosan di bidang kedokteran gigi.Kitosan (poly-β-1,4-glukosamine) merupakan makalah biopolymer alami di alam yang memiliki rantai linear denganrumus struktur (C6H11NO4)n yang dapat diperoleh dari proses destilasi kitin. Kitin ditemukan banyak pada hewan lautberkulit keras seperti blankas, kepiting, kerang, udang, rajungan, cumi-cumi, jenis serangga dan jamur. Kitosan memilikibeberapa sifat yang menguntungkan seperti biokompatibel, biodegradable, tidak beracun serta mucoadhesion sehinggakitosan sering digunakan pada pengaplikasian biomedis. Sebagai kesimpulan, kitosan dapat digunakan sebagai antibakteri, menghambat/ membunuh mikroorganisme, menurunkan rasa nyeri, serta memperbaiki sifat-sifat material dibidang kedokteran gigi.