Assessing the morphological characteristics of teeth and dental arches as potential predictors of dental crowding.

Background and aims: The early detection of dental crowding and its potential for aggravation is important during the clinical examination of mixed dentition patients, and these desiderates can be addressed by including among the clinically assessed items a series of accessible morphological characteristics of teeth and dental arches. The present study investigates possible correlations between morphological features of permanent teeth, widths of dental arches, and the onset of dental crowding during mixed dentition. Methods: A selected group of 100 class I dental casts on mixed dentition was analyzed. The dental arches were grouped as spaced, normally aligned, and crowded. The dental parameters consisted of mesiodistal dimensions of permanent teeth and specific morphological features of permanent incisors and first molars. The anterior and posterior arch widths according to Pont indices were measured. Results: Statistical analysis of data showed that mesiodistal dimensions of the permanent upper central incisors and lower incisors are significantly larger on severely crowded arches than on normally aligned arches; increased differences between mesiodistal dimensions of central and lateral permanent upper incisors and the presence of semi-shavel incisors and Carabelli cusps are associated with a greater extent of anterior crowding. The severely crowded arches presented significantly narrower anterior and posterior arch widths. Conclusions: Increased mesiodistal dimensions of permanent incisors, the presence of incisors shoveling, the Carabelli cusps on upper first permanent molars, and narrowing of dental arches during the early mixed dentition period were associated with severe dental crowding in class I cases.

Reducing Friction in Orthodontic Brackets: A Matter of Material or Type of Ligation Selection? In-Vitro Comparative Study.

(1) Background: Orthodontic appliances have changed and improved with the increasing demand for orthodontic treatment of the general population. Patients desire for shorter orthodontic treatments and for the wearing of more aesthetic devices has led to the technological development of orthodontic brackets; these were manufactured from aesthetic materials (ceramics, composite polymers) and presented different designs regarding the way archwires are ligated to the bracket. The aim of this study was to determine whether there were any differences between the static frictional forces generated by stainless steel (metallic) and polycrystalline alumina (ceramics) conventional and self-ligating brackets. (2) Methods: Static friction assessment was carried out in vitro with a universal testing machine, HV-500N-S (Schmidt Control Instruments, Hans Schmidt & Co. GmbH), intended for measuring compression and traction forces. (3) Results: The study revealed significant differences in static frictional forces at the bracket-archwire interface between the tested brackets. Stainless steel brackets produced lower static friction forces than polycrystalline alumina and self-ligating brackets generally produced lower static frictional forces than conventional brackets. The reduction of frictional forces was noticeable in the first stages of treatment, when thin, flexible orthodontic archwires (0.016" NiTi) are used. Engaged with large rectangular stainless steel archwires, (0.019 × 0.025" SS), the frictional forces produced by conventional and self-ligating metal brackets were similar, no significant differences being observed between the two types of metallic design. However, in the case of tested ceramic brackets, the results showed that the self-ligating type allows a reduction in frictional forces even in advanced stages of treatment compared to conventionally ligation. (4) Conclusions: From the perspective of an orthodontic system with low frictional forces, metal brackets are preferable to aesthetic ones, and self-ligating ceramic brackets are preferable to conventional ceramic brackets.

Vertical Cephalometric Characteristics in Class III Malocclusions.

The phenotypic variety of Angle Class III malocclusion requires in-depth investigation of the skeletal changes from a diagnostic, prognostic and therapeutic perspective alike. The aim of our study was to evaluate the particularities of vertical cephalometric parameters of patients with Class III malocclusions, according to gender and age group. Eight parameters were analyzed on lateral cephalograms of patients with Class III malocclusions and, comparatively, on lateral cephalograms of a group with Class I malocclusions. The results, grouped by gender and age, suggest that values of the gonial angle, values of the angles formed between the mandibular plane and the anterior cranial base, respectively the Frankfurt Horizontal plane were higher for patients with Class III malocclusions, differences being statistically significant especially after the pubertal growth period. Class III patients had lower values for the upper gonial angle and higher ones for the lower gonial angle. Furthermore, for patients with Class III malocclusions the Jaraback ratio decreased, based on the significantly higher values of the anterior facial height. No sexual dimorphism was associated with variation of the investigated parameters.

Undesirable dental hard tissue effects hypothetically linked to orthodontics - a microscopic study.

Like any other medical intervention, the orthodontic treatment may have, besides the positive effects, also unwanted secondary consequences. The aim of this study was to evaluate the changes present in dental hard tissue associated with orthodontic treatment. The stereo-microscopic ex vivo analysis was performed on two sets of maxillary first premolars undergoing orthodontic treatment for a long period of time (12 and 23 months); five teeth with other clinical situations were used as controls. By analyzing the teeth undergoing orthodontics, enamel color alterations were mainly found adjacent to the bracket, more pronounced in the gingival area, suggesting the need for a correct oral hygiene around it. Roughness was higher on the enamel surface corresponding to the bracket's base, aspect linked to the resign impregnation during bonding procedures. At the apical part, changes regarding contour, appearance and surface roughness were noticed. These modifications were suggestive for the presence of apical root resorption. The severity of root resorption was not correlated with the duration of treatment. In conclusion, through microscopic analysis changes that may be associated with orthodontic treatment have been observed in both crown and apical level.

Alveolar bone dehiscences and fenestrations: an anatomical study and review.

AIM: To determine the prevalence and distribution of fenestrations and dehiscences of the jaw bones among the Caucasian population, to find if any correlations can be established between their occurrence and certain teeth characteristics and to discuss the clinical implications the defects of alveolar process could have. MATERIAL AND METHODS: 138 skulls of specimens ranging from 21 to 54 years of age, having either complete dentition or reduced number of missing teeth were studied. Teeth found to have one of the two defects were examined for signs of faceting (attrition) that was considered an indicative for excessive occlusal forces and were submitted (except for the case of the third molars) to an analysis concerning their bucco-lingual inclination in the jaw. RESULTS: High-prevalence rates for both osseous entities were found. Fenestrations were present in 69.565% of the skulls and dehiscences were present in 53.623% of the skulls. More fenestrations were found in the maxilla: 74.679% and more dehiscences were found in the mandible: 71.613%. No correlations could be established between the presence of dehiscences and fenestrations and the development of high-occlusal forces, whereas all teeth affected either by dehiscences or by fenestrations were found to have modifications of the normal bucco-lingual inclination angle's values (p<0.05). DISCUSSION: The interest regarding the correlation between the alveolar processes morphology and the teeth dates back to 1963. The published studies are somewhat consistent with regard to prevalence and distribution of dehiscences and fenestrations, while opinions concerning their etiology are heterogenous. According to our study and the data provided by the specialized literature references, dehiscences and fenestrations are common findings related to the presence of the teeth. CONCLUSIONS: The potential of developing fenestrations and dehiscences must be carefully evaluated through oral surgery procedures. With regard to implant placement, this study aims to help the clinician design and manage treatment, in order to clinically correct the conditions and identify the principles of bone augmentation, so that endo-osseous implants can be properly placed.

[Oral appliances in the treatment of respiratory disturbances in sleep--from goals to outcomes]. / Terapia cu dispozitive orale a tulburarilor respiratorii in somn--de la objective la rezultate.

PURPOSE: To synthetically present the current state of knowledge regarding the use of oral devices for the treatment of sleep breathing disorders, according to the data provided by the specialised literature references. MATERIAL AND METHODS: A MEDLINE search was performed, alongside with a hand search of periodicals in the field. RESULTS: 172 articles were identified, out of which 86 for pneumologists, 7 for otorhinolaryngologists and 79 for dentists. DISCUSSIONS: Data obtained from the specialised literature indicate that oral devices represent a viable alternative in the treatment of sleep breathing disorders, due to their low cost and to the relative comfort their wearing offers to the patients, as such solutions are better tolerated than other treatments. Despite the numerous controversies regarding the efficacy of oral devices in the treatment of snoring and obstructive sleep apnoea (OSA), their use for cases of mild OSA is accepted by numerous specialists, and the competence is delegated to the dentist, specifically to the orthodontics and dento-facial orthopaedics specialists. CONCLUSIONS: Oral devices treatment represents an opportunity for the dentist to contribute to the efficient treatment of many patients with the OSA syndrome, in close cooperation with other sleep medicine specialists.