Are chin and symphysis morphology facial type-dependent? A computed tomography-based study.

Introduction: The chin is a major determinant of the facial profile; hence, it plays a major role in orthodontics and orthognathic surgery. It is thus essential to follow and better understand its expression in different facial types. The major objectives of the current study were to characterize morphometrically the chin and symphysis and reveal their association with different facial types.

Upper Lip Horizontal Line: Characteristics of a Dynamic Facial Line.

Upper lip appearance received major attention with the introduction of diverse treatment modalities, including lip augmentation, rhinoplasty surgery, and dental treatment designed to support the upper lip. Our objectives were to define the prevalence and characteristics of the upper lip horizontal line (ULHL), which is a dynamic line appearing during a smile, in relation to gender, malocclusions, aging, and facial morphology. First, the prevalence and gender distribution of ULHL was examined from standardized en-face imaging at full smile of 643 randomly selected patients.

Variation in Chin and Mandibular Symphysis Size and Shape in Males and Females: A CT-Based Study.

The chin is a unique anatomical landmark of modern humans. Its size and shape play an important role from the esthetic perspective. However, disagreement exists in the dental and anthropological literature regarding the sex differences in chin and symphysis morphometrics.

Rate and pattern of interproximal dental attrition.

Although occlusal and interproximal attrition occur because of diverse etiology and present dissimilar features, both progress with age. The objectives of this study were to reveal the rate and pattern of development of interproximal attrition facets (PAF) with age and to compare those with occlusal attrition (OA) changes. Five-hundred and ninety-four teeth were collected from 198 skulls (of adults, 20-71 yr of age).

Pattern of maxillary and mandibular proximal enamel thickness at the contact area of the permanent dentition from first molar to first molar.

Introduction: Proximal enamel thickness (PET) at the mesial and distal contact areas of the complete permanent dentition has not been previously reported. Anatomic investigation of PET is essential for interproximal reduction treatment. Our objectives were to measure the PETs of the complete maxillary and mandibular dentitions at the contact areas, to compare the PETs of adjacent teeth, and to evaluate the vertical position of each contact area.

Long- and short-term effects of headgear traction with and without the maxillary second molars.

Introduction: A quantitative assessment of maxillary first molar distalization with and without the maxillary second molar (M2) was carried out.

Methods: Fifty-six cervical headgear patients undergoing fixed appliance orthodontic treatment were divided into 2 groups: before (G - M2) and after (G + M2) eruption of the maxillary second molars (ages, 11.87 ± 1.

Proximal attrition facets: morphometric, demographic, and aging characteristics.

Although interproximal attrition is considered to be limited in modern populations, it has important clinical implications. However, in contrast to occlusal attrition, proximal attrition receives limited scientific attention. The main purpose of the current study was to fill this void.

An ortho-surgical approach to severe impaction using bone crestal bridge: a case report.

Impaction of both mandibular canine and lateral incisor is a rare clinical finding which is often treated by way of surgical extraction. This decision is often taken because of the anatomical limitations presented by the mandible, and the horizontal position of the impacted teeth, which have occasionally transmigrated, placing them in close proximity to the roots of neighboring teeth and with a high risk for causing their resorption. In addition, this condition significantly increases the likelihood that the area involved will undergo gingival recession and loss of crestal bone if an unsophisticated ortho-surgical approach is undertaken.

Malocclusion in early anatomically modern human: a reflection on the etiology of modern dental misalignment.

Malocclusions are common in modern populations. Yet, as the study of occlusion requires an almost intact dentition in both the maxilla and mandible, searching for the ultimate cause of malocclusion is a challenge: relatively little ancient material is available for research on occlusal states. The Qafzeh 9 skull is unique, as its preserved dentition allowed us to investigate the presence and manifestations of malocclusion.

Efficacy of three hygienic protocols in reducing biofilm adherence to removable thermoplastic appliance.

Objectives: To examine the ability of a removable thermoplastic appliance (RTA) to adsorb hygienic solutions and inhibit bacterial growth and to examine the efficacy of three hygiene protocols in reducing bacterial biofilm adherence to RTA.

Materials And Methods: Solution adsorption and bacterial growth inhibition were examined in vitro using paper vs RTA discs. Subsequently, 11 patients treated with RTA (mean age, 29.

The arrangement of the interproximal interfaces in the human permanent dentition.

Objectives: The interproximal interface (IPI) is the interface between two adjacent teeth, i.e., the site where forces are transmitted along the dental arch.

In-vivo von Mises strains during Invisalign treatment.

Introduction: The Invisalign (Align Technology, Santa Clara, Calif) force delivery system has not been investigated. Since forces are related to the strains developed on the aligner surface, the behavior of the maxillary incisor and premolar von Mises strains (IVM, PVM) were studied during biweekly wear of an aligner.

Methods: Maxillary aligners (n = 61) were examined from 3 patients requiring maxillary incisor retraction and stationary anchored premolars.

Incremental growth of the maxillary tuberosity from 6 to 20 years-A cross-sectional study.

Objectives: Although the maxillary tuberosity (MT) is a major growth site of the maxilla, its time-related growth was not fully investigated. The objectives of the study were to evaluate the MT growth from 6 to 20 years of age defining the peak growth age and to assess time-related indicators.

Design: Panoramic radiographs from 189 patients were divided in a cross-sectional study into six age groups.

Duration of elastomeric separation and effect on interproximal contact point characteristics.

Introduction: The common protocol of a week-long duration of elastomeric separators to facilitate band placement usually causes discomfort. In this study, we examined the minimum separation time required to create an interproximal space >0.16 mm (band thickness), the interproximal changes over 24 hours after separator removal, and the mechanical characteristics of various separators.

Duration and anchorage management of canine retraction with bodily versus tipping mechanics.

Objective: To compare tipping mechanics (TM) and bodily mechanics (BM) with respect to duration, angulation, and anchorage loss during canine retraction.

Materials And Methods: TM and BM brackets were bonded to the upper right and left canines, respectively, of 14 subjects requiring maxillary first premolar extractions. The upper canines were retracted with variable nickel titanium closed coil springs (F = 0.

Labial cervical vertical groove (LCVG) distribution and morphometric characteristics.

Objective: Labial cervical vertical groove (LCVG), a dental anomaly found at the cervical region of upper permanent incisors, can be of esthetic, periodontal and prosthetic concern. The aim of this study was to define the prevalence and characteristics of LCVG.

Design: Of the 1250 examined subjects, 66 exhibited an LCVG.

Periodontal healing following orthodontic movement of rat molars with intact versus damaged periodontia towards a bony defect.

The aim of this research was to determine whether orthodontic tooth movement influences periodontal healing. In 16 male Wistar rats, 12 week of age, a bony defect was created mesial to both maxillary first molars, not including the attachment apparatus (group 1), and in 15 animals, the defect included the periodontal ligament (group 2). In both groups, the right first molar was moved mesially (orthodontic side) for 2 weeks followed by a 1-week retention period; the contralateral molar was not moved (control side).

Bracket placement in lingual vs labial systems and direct vs indirect bonding.

Objective: To examine the ultimate accuracy of bracket placement in labial vs lingual systems and in direct vs indirect bonding techniques.

Materials And Methods: Forty pretreatment dental casts of 20 subjects were selected. For each dental cast, four types of bracket placement were compared: labial direct (LbD), labial indirect (LbI), lingual direct (LgD), and lingual indirect (LgI).

Gene profile in periodontal ligament cells and clones with enamel matrix proteins derivative.

Aim: Evaluate enamel matrix proteins derivative effect on gene expression profiles in cultured human periodontal ligament cell population and its clones.

Material And Methods: Human periodontal ligament (PDL) cells were explanted. Cell cloning was performed and clones classified into fibroblastic (FB) and mineralized tissue forming (MTF) according to their capacity to express alkaline phosphatase and form mineralized tissue.

Centric slide, bite force and muscle tenderness changes over 6 months following fixed orthodontic treatment.

Objective: The postorthodontic change of the masticatory muscles was evaluated using three parameters: maximal voluntary bite force (MVBF), slide in centric (difference between maximal intercuspation and retruded contact position), and muscle sensitivity to palpation.

Materials And Methods: MVBF was measured with a custom-made rubber tube bite force device, centric slide with a digital caliper, and sensitivity to palpation of the masseter and temporalis muscles (scale 0-3) during application of standardized digital force (10 N). Data were collected at four time points: T0, before bracket removal; T1, immediately after bracket removal; T2, after 3 months of retention; and T3, after 6 months of retention.

Assessment of open and incomplete bite correction by incisor overlap and optical density of polyvinyl siloxane bite registration.

Open bite (OB) is a generalized term, which could incorporate subgroups that react differently to vertical correction. The objectives of the present study were to detect vertical treatment changes in incomplete bite (IB: inter-incisor overlap with no lower incisor contact with teeth or palate) and OB (no inter-incisor overlap) groups compared with a complete bite (CB: inter-incisor overlap with full lower incisor contact with teeth or palate) control group, to evaluate treatment response of the central and lateral incisors, and to study the vertico-sagittal interaction. Dental casts were taken at three time points, pre-treatment, post-treatment, and after one year of retention, from 54 Class II patients (22 males and 32 females with a mean age of 11 years 6 months) divided into three groups: CB (n = 21), IB (n = 18) and OB (n = 15).

Unequal outer and inner bow configurations: comparing 2 asymmetric headgear systems.

Introduction: Asymmetric headgear is used when different molar distalization forces (MDF) are needed on the right and left sides of the jaw to correct a Class II molar relationship.

Methods: We investigated 2 asymmetric headgear configurations, the outer-bow and the inner-bow, on cervical-pull headgear. In the first configuration, 5 hooks were soldered on 1 side of the outer bow at 10-mm intervals, making this side shorter; in the other, 4 stops (1.

Labial-cervical-vertical groove in maxillary permanent incisors--prevalence, severity, and affected soft tissue.

Objectives: To investigate the prevalence and severity of a labial-cervical-vertical groove (LCVG) in maxillary permanent incisors and its effect on the associated gingival tissue.

Methods: A total of 600 adolescents (293 boys and 307 girls, mean age 13.6+/-1.

Skeletal and dental response to rapid maxillary expansion with 2- versus 4-band appliances.

Purpose: Banding a rapid palatal expansion (RPE) appliance to the 2 first molars has been proposed as an equivalent to the conventional 4-band RPE appliance. However, the dentoskeletal response to this treatment has not been evaluated.

Material: Twenty-eight subjects (aged 8-20 years) who required maxillary expansion were matched by age and randomly assigned to either a 2-band or a 4-band RPE group.

In vivo debonding strength and enamel damage in two orthodontic debonding methods.

Bracket debonding strength related to diverse debonding methods and enamel damage has not been assessed in vivo. The study hypothetized a direct relationship between these three parameters. Debonding strength was measured clinically in the wings method and base method on 50 patients in a split mouth method using a calibrated debonding plier.