Statistical Study Concerning Extraction and Non-Extraction Methods in Orthodontic Treatments.

INTRODUCTION: The need to extract permanent teeth for the correction of dento-maxillary anomalies remains even today a controversy in orthodontic therapy. The purpose of this study was to assess the orthodontist's point of view on the extraction and non-extraction methods used in orthodontic treatments, regarding clinical experience. MATERIAL AND METHODS: A de novo conceived questionnaire was elaborated by means of Google Forms and it comprised 22 questions regarding gender, age, different proprieties and aspects of both extraction and non-extraction methods and the percentage of treated patients who developed an increase in dental sensitivity and caries activity following the therapeutic stripping procedure. RESULTS: 204 orthodontists answered the questionnaire. The respondents chose dental stripping (IPR-interproximal reduction) as the most used non-extraction method in their orthodontic practice with 34,3%, followed by over-expansion and dental stripping 24%. The probability that females will try to avoid dental extractions is 1.888 times higher compared to males. The association is statistically significant (p-value 0.0336). 70,1% of clinicians state that they use dental stripping as a non-extraction method to gain space even when there is NO Bolton discrepancy. In Class III cases, for reducing crowding and correcting the dental relations, 65.2% of doctors opt for dental stripping, while 34.8% do not avoid the extraction of a lower incisor. CONCLUSIONS: Among the non-extraction methods for creating space, the most used by the surveyed orthodontists was dental stripping IPR. Tooth extraction remains a solution used by orthodontists for treating dentomaxillary disharmonies with crowding.

Comparative Evaluation of Dental Enamel Microhardness Following Various Methods of Interproximal Reduction: A Vickers Hardness Tester Investigation.

Interproximal enamel reduction, also known as stripping, is a common orthodontic procedure that reduces the mesiodistal diameter of teeth, allowing for a balance of available space in dental arches. The aim of this study was to assess the enamel surface microhardness resulting from the application of currently available methods for interproximal reduction. Forty-two extracted human permanent teeth were divided into six different groups, each subjected to a therapeutic stripping procedure using various methods (i.e., diamond burs, abrasive strips of 90 µm, 60 µm, 40 µm, and 15 µm, and abrasive discs). Stripping was performed by a single individual in accordance with the manufacturers' recommendations for the various systems used. One of the proximal faces of the tooth underwent IPR, while the other side remained untreated for control. The hardness of the enamel surface was measured using a Vickers hardness tester. The control group achieved the hardest enamel surface (354.4 ± 41.02 HV1), while the lowest was observed for enamel surfaces treated with 90 µm abrasive strips (213.7 ± 118.6). The only statistically significant difference was identified in comparisons between the values measured for the control group and those obtained after stripping with diamond burs (p = 0.0159). Enamel microhardness varied depending on the stripping instrument used, but no statistically significant differences were found (p > 0.05). Optimal microhardness values, close to those of healthy enamel, were achieved after mechanical treatment with 15 µm abrasive strips and abrasive discs. Dental stripping is a safe therapeutic procedure that has a relatively minor influence on the microhardness of surface enamel.

A Comparative Analysis of Enamel Surface Roughness Following Various Interproximal Reduction Techniques: An Examination Using Scanning Electron Microscopy and Atomic Force Microscopy.

Interproximal enamel reduction (IER) is a minimally invasive therapeutic procedure commonly used in orthodontics to address both functional and aesthetic issues. Its mechanical effects on enamel surfaces induce the formation of grooves, furrows, scratches, depressions, and valleys. The aim of this study was to assess the enamel surface roughness resulting after the application of currently available methods for interproximal reduction. Ninety freshly extracted human teeth were divided into six groups and subjected to the stripping procedure, using a different method for each group (diamond burs, abrasive strips of 90 µm, 60 µm, 40 µm, 15 µm, and abrasive discs). A single individual performed stripping according to the manufacturer's recommendations, involving interproximal reduction on one tooth's proximal face and leaving the other side untreated. Qualitative and quantitative assessment of the enamel surfaces was carried out using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), obtaining 2D and volumetric 3D images of the enamel surface microstructure and nanostructure. The study found that diamond burs and abrasive strips of 60 µm and 90 µm increased enamel roughness due to intense de-structuring effects, while the 40 µm polisher had a gentler effect and 15 µm abrasive strips and polishing discs preserved enamel surface quality and removed natural wear traces.

Comparative Evaluation of Two Bracket Systems' Kinetic Friction: Conventional and Self-Ligating.

Friction is an intensely studied feature in orthodontics, as the sliding mechanics approach remains one of the most utilized techniques in current practice, and the question of whether self-ligating brackets produce less friction than conventional brackets still stands. The objective of this study was to compare a self-ligating system with different closing mechanisms and a conventional system with different ligating mechanisms regarding their frictional properties. Laboratory measurements were performed using an advanced materials testing machine generating tensile strength and load at maximum Load values, which were statistically analyzed and compared. These two parameters have been associated with the frictional resistance generated at the archwire-bracket slot interface. Statistically significant results were obtained when comparing the active self-ligating brackets with the passive self-ligating (tensile strength mean 1.953, SD 0.4231; load at maximum moad mean 6.000, SD 1.3000) and conventional brackets (tensile strength mean 1.953, SD 0.4231; load at maximum load mean 6.000, SD 1.3000), as well as when comparing the passive self-ligating brackets with the conventional brackets (tensile strength mean 1.708, SD 0.8628; load at maximum load mean 5.254, SD 2.645). The active self-ligating brackets tended to produce more friction when compared to the passive self-ligating brackets but were similar to conventional brackets with stainless steel ligatures.

Comparative Evaluation of Two Bracket Systems' Bond Strength: Conventional and Self-Ligating.

Adhesion remains a key element in dentistry, whether approached in prosthetics, odontology, or orthodontics. It is a continuously researched aspect, as improved materials and adhesive methods keep emerging in the market. No orthodontic treatment can be effective without the proper adhesion strength of the bonded elements on the teeth. The objective of this research, in the broad context of self-ligating versus conventional brackets, was to compare active and passive self-ligating systems with a conventional one by conducting an in vitro study on human-extracted premolars. Shear bond strength tests were executed by means of an advanced materials-testing machine that generated maximum load and tensile strength values. The data obtained underwent statistical analysis with a statistical threshold of p < 0.05. The results regarding the statistical significance were acquired when comparing the passive self-ligating system with the active self-ligating and conventional systems (load-at-maximum-load mean 204.9, SD 91.09, and p < 0.05). In this study, the passive self-ligating bracket system appears to present increased shear bond strength.