Dental Hypotheses
Volume:5 Issue: 4, Oct-Dec 2014

To investigate the effects of different clinical and technical conditions on the accuracy of electronic apex locators (EALs). «Tooth apex,» «dental instrument,» «odontometry,» «electronic medical,» and «electronic apex locator» were searched as primary identifiers via Medline/PubMed, Cochrane library, and Scopus data base up to 30 July 2013. Original articles that fulfilled the inclusion criteria were selected and reviewed. Out of 402 relevant studies, 183 were selected based on the inclusion criteria. In this part, 75 studies are presented. Pulp vitality conditions and root resorption, types of files and irrigating materials do not affect an EAL''s accuracy; however, the file size and foramen diameter can affect its accuracy. Various clinical conditions such as the file size and foramen diameter may affect EALs'' accuracy. However, more randomized clinical trials are needed for definitive conclusion.

Tooth wear - attrition, abrasion, or erosion - are modern day problems for dentistry. It usually leads to discomfort and sensitivity especially during eating, drinking, or tooth brushing. If left untreated for a long time, it may lead to loss of vitality of tooth. Various qualitative and quantitative methods have been used in the past to describe tooth wear. However, each method has certain shortfalls. There is no ideal index that is simple and clear in its scoring criteria. The Hypothesis: The classifications described in the literature are very descriptive and hence, it takes a long time to grade for a complete dentition. Some are based on the morphologic appearance and others on severity. A classification system has to facilitate standardized identification of a condition and help in diagnosis and treatment planning. The present manuscript is an attempt to emphasize the need to develop a classification system that is easy to score and describes the condition in details without utilizing much time. Evaluation of the Hypothesis: The hypothesis highlights some drawbacks of the classification systems available today and puts forth a new and easy to use classification system.

Orthodontic elastic has been investigated for tooth movement. Study about their use in treatment of jaw fractures is limited. This study is designed to measure force relaxation of 3/16 inch heavy latex orthodontic elastics in jaw fracture treatment simulated conditions. This study is designed to study the force relaxation of 45 heavy 3/16 inch orthodontic elastic (American Orthodontist, AO) (4/8 mm internal diameter) were measured using Zwick testing machine (Zwick GmbH & Ulm Germany) in 0, 1, and 14 days of immersion in simulated oral environment. In each of these three occasions, 15 specimens were placed in jigs with metallic pins that inserted 15 mm and 20 mm apart that is equivalent to the normal inter-arch space in a closed mouth position. The jigs were incubated in 37°C and each 24 hours they received 10 thermal cycles of 55°C and 5°C for 30 seconds in a thermocycle. The distribution of the data was evaluated by Klomogrov-Simirnov test and after confirmation of a normal distribution; data was analyzed using analysis of variance (ANOVA). Mean force decay at 15 mm stretch was significantly differ between 0-1 days and 0-14 days (P < 0.05) but was not significantly differ between 1-14 days. The same relations exist for 20 mm stretch. This study creates scientific basis for use of orthodontic elastics in treatment of fractured jaws.

Globally, non-communicable diseases are increasingly recognized as a major cause of morbidity and mortality. Among them, overweight and obesity are imperative. The problem of overweight and obesity is not confined to adults but also to children and adolescents. The present changing dietary pattern among children is contributing to childhood overweight and on other hand stands as a risk factor in the development of dental caries, hence the study aimed to investigate the relation between overweight and dental caries among school children. A cross-sectional study was conducted among 5-6-year and 12-year-old school children to evaluate the relation between body mass index (BMI) and dental caries. Using stratified random sampling technique 1017 school children were selected. Subjects who have brought consent from their parents were included and subjects who were absent on the day of examination were excluded. A pre-structured questionnaire was prepared to collect data regarding demographic details, oral hygiene practices, dentition status and treatment needs, (BMI), 24-hour diet history, physical activity, and television watching. The data collected were subjected to statistical analysis (SPSS V 16. 0) using Chi-square and multivariate logistic regression tests. «Risk of overweight» 20% and an «overweight» of 40% were observed. With BMI, parental overweight (P = 0. 001), socioeconomic status (SES) (P = 0. 001), physical activity (P = 0. 001) and television watching (P = 0. 001) were found to be statistically related. Body mass index and dental caries were not statistically related. These complex and multifactorial relations like overweight and dental caries may involve many unknown factors which warrant exploration on larger population.

Bone tissue engineering proposes a suitable way to regenerate lost bones. Different materials have been considered for use in bone tissue engineering. Hydroxyapatite (HA) is a significant success of bioceramics as a bone tissue repairing biomaterial. Among different bioceramic materials, recent interest has been risen on fluorinated hydroxyapatites, (FHA, Ca 10 (PO 4) 6 F x (OH) 2−x). Fluorine ions can promote apatite formation and improve the stability of HA in the biological environments. Therefore, they have been developed for bone tissue engineering. The aim of this study was to synthesize and characterize the FHA nanopowder via mechanochemical (MC) methods. Natural hydroxyapatite (NHA) 95.7 wt.% and calcium fluoride (CaF 2) powder 4.3 wt.% were used for synthesis of FHA. MC reaction was performed in the planetary milling balls using a porcelain cup and alumina balls. Ratio of balls to reactant materials was 15:1 at 400 rpm rotation speed. The structures of the powdered particles formed at different milling times were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fabrication of FHA from natural sources like bovine bone achieved after 8 h ball milling with pure nanopowder. F− ion enhances the crystallization and mechanical properties of HA in formation of bone. The produced FHA was in nano-scale, and its crystal size was about 80-90 nm with sphere distribution in shape and size. FHA powder is a suitable biomaterial for bone tissue engineering.

Root resorption has various etiologies. Recent studies have demonstrated a periroot sheet covering the root. The outermost layer of this sheet is the Malassez'' epithelial layer. Tooth malformations are seen in ectodermal dysplasia and it is believed that the ectodermal layer in the periroot sheet differs in cases of ectodermal dysplasia. Case reports: Three cases of unexpected severe root resorption are demonstrated. Two cases were diagnosed with ectodermal dysplasia and the third appeared with thin, curly hair and absence of eyebrows but no ectodermal diagnosis. In the ectodermal cases, there were severe orthodontically provoked resorptions on the teeth that appeared to be permanent but were possibly primary. In the third case, there was heavy resorption on permanent teeth due to orthodontic treatment. The orthodontist should be aware that aggressive resorption can occur in cases not diagnosed with ectodermal dysplasia but with signs of ectodermal deviations, and that tooth morphology, hair, and skin are important to observe before proceeding with treatment.

The use of osseointegrated extraoral implants for retention of extraoral prostheses, such as ears offers ideal support and retention, and improves patient''s appearance and quality of life. However, the best result may be obtained only by careful planning number, position and orientation of the implants and this article presents a method of making of a surgical stent that is simple, economic and stable during all phases of surgery. Case Report: A 26-year-old male (without any remarkable systemic disorder) presented with congenital defect in one ear. An impression was made of congenital defect in left ear, wax pattern of defect and missing ear is made, the wax prosthesis is changed into a clear acrylic resin, and on the other hand an occlusal maxillary splint is also fabricated with clear acrylic resin. The occlusal splint and the acrylic resin ear are joined together using an extraoral bar that is made of proper length of wax and also is checked on patient''s face and processed into a clear acrylic resin. By this kind of surgical guide, we can determine the best location of the implants and location of the implants will not compromise to fabricate ear prostheses with ideal form and location. This surgical guide can be used for the pretreatment of radiographic stent.

This report presents a case to show inflammatory root resorption can be successfully treated by using mineral trioxide aggregate (MTA). Case Report: A central maxillary incisor of an eight-year-old boy was avulsed associated with crown fracture secondary to a fall. The tooth was stored in ice. Early attempts at pulpal revascularization of the replanted tooth proved unsuccessful. To stop inflammatory root resorption, long-term calcium hydroxide therapy was employed. Despite the use of calcium hydroxide, resorption continued. Subsequent to the failure of that treatment, MTA was used as a root canal filling material. At 20-month follow-up, the tooth was asymptomatic and had clinical signs of ankylosis but external inflammatory root resorption had stopped. MTA may be considered as an alternative option for the treatment of continuous external inflammatory root resorption.