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Biomedical subjects

Silvia Geron

Publications and source records attributed to Silvia Geron.

7 recordsLinked to original sources
PubMed2005

Influence of sex on the perception of oral and smile esthetics with different gingival display and incisal plane inclination.

This study was designed to determine the esthetic perception of men and women to variations in upper and lower gingival display at smile and speech and to incisal plane tilting. Composed photographs of smile and speech with varying amounts of gingival exposure of the upper and lower teeth and gingiva at smile and at speech and with varying degrees of incisal plane tilting were rated for attractiveness by two groups of lay people. The images were presented as male or female images. A total of 300 questionnaires, including 7500 images, were evaluated by 100 subjects. The results showed that images were scored as less attractive as the amount of upper and lower gingival display was increased during smile and speech. The amount of gingival exposure graded in the esthetic range was up to one mm for the upper incisors and zero mm for the lower incisors. Incisal plane tilting was graded as unesthetic when above two degrees of deviation from the horizontal. Male and female evaluators scored images differently with upper gingival exposure. Female evaluators gave statistically significant higher scores than male evaluators to upper gingival exposure images at smile and speech of both males and females, suggesting that females are more tolerant of upper gingival exposure. Images were scored differently when presented as male or female images. Female images were scored lower by both male and female evaluators, suggesting that additional efforts should be taken in female patients to achieve an esthetic result.

Adult↗
PubMed2004

Vertical forces in labial and lingual orthodontics applied on maxillary incisors--a theoretical approach.

Theoretical and experimental biomechanical analyses explain most labial orthodontics (LaO); however, lingual orthodontic (LiO) biomechanical principles are rarely introduced. The objective of this study was to apply basic biomechanical considerations in understanding the influence of maxillary incisor inclination and to compare the effect of labial vs lingual intrusive/extrusive forces on tooth movement. Basic anatomic and geometric hypotheses were assumed, ie, tooth length (crown and root), location of the center of resistance, and crown thickness. Incisor inclination as related to a perpendicular line to the occlusal plane (OP) varied between -35 degrees (retroclination) and 45 degrees (proclination). A 0 degrees inclination was defined as a tooth position with its long axis perpendicular to the OP. The buccolingual moment for characterizing root movement was calculated for an applied force perpendicular to the OP. The results showed that when using LaO, an extrusion force resulted in labial root movement from a retroclination of 20 degrees up to a proclination of 45 degrees. In LiO, labial root movement occurred only when the tooth was proclined more than 20 degrees. In all other tooth inclinations, lingual root movement occurred. The opposite tooth movement occurred when an intrusive force was applied. Application of a vertical force has different clinical effects on tooth movement with labial and lingual appliances. Application of a lingual force is more complicated, and its effect on tooth movement depends on bracket position and initial tooth inclination.

Alveolar Bone Loss↗
PubMed2004

Managing the orthodontic treatment of patients with advanced periodontal disease: the lingual appliance.

AIM: Treatment of adult patients with advanced periodontal disease is a challenge to the orthodontist using lingual appliance therapy, which is the preferred technique for many adult patients due to its relative invisibility. The lingual technique has been shown to be capable of correcting severe malocclusions, deep bite as well as open bite cases. However, the treatment mechanics are different from the labial technique and require different considerations. METHODS: The potential problems during lingual orthodontic treatment of patients with advanced periodontal disease are discussed, including esthetics during and after orthodontic treatment, efficacy of treatment, adaptation of biomechanics, etc. Three cases are presented to demonstrate the problems and solutions. CONCLUSION: Successful treatment of patients with advanced periodontal disease using the lingual appliance requires specific considerations and a biomechanical approach.

Biomechanical Phenomena↗
PubMed2003

Anchorage loss--a multifactorial response.

Anchorage loss (AL) is a potential side effect of orthodontic mechanotherapy. In the present study, it is defined as the amount of mesial movement of the upper first permanent molar during premolar extraction space closure. In addition, AL is described as a multifactorial response in relation to the extraction site, appliance type, age, crowding, and overjet. For this study, 87 university clinic and private practice subjects, who were defined as maximum anchorage cases and had undergone bilateral maxillary premolar extractions, were divided into four groups according to extraction site (first vs second premolars), mechanics (lingual vs labial edgewise appliances), and age (adolescents vs adults). Overjet and crowding were examined from the overall sample. Data were collected from serial lateral cephalograms and dental casts. The results showed that as the severity of dental crowding increased, AL significantly decreased (r = -0.66, P = .001). Labial edgewise appliances demonstrated a significantly greater AL than did lingual edgewise appliances (1.15 +/- 2.06 mm, P < .05). A greater, though not statistically significant, AL was found in adults than in adolescents (0.73 +/- 1.43 mm). There was a slight nonsignificant increase in AL between maxillary second compared with first premolar extractions (0.51 +/- 1.33 mm). Overjet was weakly correlated to AL. These results suggest that AL is a multifactorial response and that the five examined factors can be divided into primary (crowding, mechanics) and secondary factors (age, extraction site, overjet), in declining order of importance.

Adolescent↗
PubMed2002

Lingual forced eruption orthodontic technique: clinical considerations for patient selection and clinical report.

Lingual forced eruption is a treatment modality that minimizes esthetic impairment during orthodontic treatment. Use of this technique can enhance the acceptance of orthodontic treatment by adult patients and minimize unnecessary compromises in the treatment planning of submerged roots. In this clinical report, a treatment modality for forced eruption therapy is described, clinical considerations for patient selection are identified, and the advantages and limits of the lingual orthodontic technique are discussed.

Crown Lengthening↗