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At least 55 records · Page 3Linked to original sources
PubMed2005

Magnetic resonance imaging of the condylar growth pattern and disk position after chin cup therapy: a preliminary study.

This study was conducted on lateral cephalograms and magnetic resonance images (MRIs) obtained from 20 subjects with Class III malocclusion. Only clinically temporomandibular joint (TMJ) symptom-free subjects were included in this study. In the treatment group, a chin cup with 600 g of force was applied in 13 patients (10 girls and three boys) with a mean age of nine years. The chin cup was applied in a direction from the chin toward the TMJ. The control group consisted of seven patients (six girls and one boy) with a mean age of eight year nine months. Orthodontic treatment was not applied in the control group. Records were taken at the beginning and end of chin cup therapy from all the subjects. Measurements were made on lateral cephalograms and unilateral-left sagittal-oblique TMJ MRIs. Variables obtained at the beginning and end of the study were compared by Student's t-tests and paired t-tests. Relationships between craniofacial and TMJ variables were analyzed by correlation analysis. The mandibular corpus length was increased and condylar head angle was decreased by chin cup therapy. A positive correlation existed between activation of sagittal maxillary and mandibular growth and bending of the condylar head. This study showed that the condylar growth pattern was altered by chin cup. It may be implied that the source of improvement is adaptation of the craniofacial structures to the changes of the condylar growth pattern produced by the chin cup.

Cephalometry↗
PubMed1991

Pediatric chin injury: occult condylar fractures of the mandible.

The diagnosis of occult mandibular condylar fractures in children is often missed or delayed on initial examination when children present with a laceration to the chin. A clue to the diagnosis of this type of skeletal injury to the mandible is the knowledge of a commonly occurring pattern of injury associated with chin trauma. Chin laceration, fracture of the parasymphyseal region near the chin, and fracture of the condyles are often concomitant injuries of the mandible. This article reviews three case reports of children who sustained a chin laceration, fracture in the region near the chin, and fracture to the mandibular condyles secondary to chin trauma that were not initially diagnosed on clinical examination.

Child↗
PubMed2003

Significance of chin-brow vertical angle in correction of kyphotic deformity of ankylosing spondylitis patients.

STUDY DESIGN: A prospective study. OBJECTIVES: To assess the significance of chin-brow vertical angle in planning and evaluating the correction of kyphotic deformity with ankylosis of the cervical spine in ankylosing spondylitis patients. SUMMARY OF BACKGROUND DATA: Accurate assessment and measurement of spinal kyphotic deformity is required when planning treatment and assessing its results. METHODS: Thirty-four ankylosing spondylitis patients with cervical ankylosis who had undergone pedicle subtraction extension osteotomy for correction of kyphotic deformity were studied. Radiographic assessment for sagittal balance was performed by measuring thoracic kyphosis, lumbar lordosis, the distance between the vertical line on the anterosuperior point of T1 and that of S1, and sacral inclination. Chin-brow vertical angle was measured on the clinical photos of the patients. Clinical outcomes were assessed by a questionnaire. RESULTS: The preoperative and postoperative chin-brow vertical angles were 35.5 degrees and 1.8 degrees, respectively. Final follow-up radiographs showed an increase in lumbar lordosis from 5.5 degrees to 43.2 degrees (an increase of 37.7 degrees ), and thoracic kyphosis remained stable from 50.4 degrees to 50.2 degrees. Sagittal imbalance significantly improved from 101.5 mm to 12.7 mm. The decreased chin-brow vertical angle correlated negatively with the correction angle. The patients with a chin-brow vertical angle of less than -10 degrees had significantly low scores on horizontal gaze. CONCLUSIONS: Chin-brow vertical angle was an objective index for evaluating horizontal gaze. Based on the results of this study, measurement of chin-brow vertical angle is recommended for planning correction of kyphosis and accurate evaluation of treatment outcome.

Adult↗
PubMed2006

Orthodontic treatment changes of chin position in Class II Division 1 patients.

INTRODUCTION: Because most patients with skeletal Class II malocclusions also have mandibular deficiencies, treatment plans should include improvement in chin projection. On that basis, the purposes of this study were to (1) determine how Class II treatment affects anteroposterior (AP) chin position in growing subjects and (2) ascertain the most important determinants of AP chin position. METHODS: Pretreatment and posttreatment lateral cephalograms of 67 treated patients (25 extraction headgear and Class II elastics, 23 nonextraction headgear, and 19 Herbst) were collected, traced, and digitized. The average pretreatment age was 12.2 years (range, 9-14 years), and the average treatment duration was 30.2 months (range, 17-65 months). Cephalometric changes were compared with 29 matched untreated Class II controls. Mandibular superimpositions were used to evaluate condylar growth and true mandibular rotation. RESULTS: All 3 treatment methods produced normal dental relationships and restricted or inhibited AP maxillary growth, with no significant improvement of AP chin position. Differences between changes in vertical position of the maxilla, maxillary and mandibular molars, and condylar growth could not reliably predict changes in chin position. Analyses demonstrated that true mandibular rotation was the primary determinant of AP chin position. Stepwise multiple regression showed that, combined with true mandibular rotation, condylar growth and movements of the glenoid fossa accounted for 81% of the variation in AP changes of pogonion. CONCLUSIONS: Contemporary treatments do not adequately address mandibular deficiencies. Future treatments must incorporate true mandibular rotation into Class II skeletal correction.

Adolescent↗
PubMed1999

Comparison of chin and jaw movements during gum chewing.

STATEMENT OF PROBLEM: Knowledge of mastication is based on studies that use jaw tracking equipment in nonroutine settings. Ethologists would argue that such data probably does not reflect routine masticatory function. If jaw movements could be tracked noninvasively, then the hypothesis that jaw tracking equipment and nonroutine settings alter mastication could be investigated. PURPOSE: This study quantitatively evaluated the relationship between chin and jaw movements during a gum-chewing task. MATERIAL AND METHODS: Masticatory chin and jaw movements of 50 subjects were tracked in the x-, y-, and z-axes for 15 seconds, which resulted in approximately 15 chewing cycles obtained per subject. For each chewing cycle, magnitude and timing of displacement, velocity, and acceleration extrema in each axis were computed for both jaw and chin movement data. Extrema means were calculated for each 15-second trial. The respective means representing chin versus jaw movements were compared with linear regression and correlation analyses. RESULTS: All mean extrema were significantly correlated (r range 0. 30-0.99; P <.05). Magnitude correlations were larger than timing correlations for acceleration extrema. In contrast, magnitude correlations were smaller than timing correlations for displacement extrema. The highest correlation occurred for chewing rate. CONCLUSIONS: Chin and jaw movements were correlated during chewing; however, only chewing rate was highly predictable from chin movement data.

Acceleration↗
PubMed2001

Morbidity of chin bone harvesting.

The chin is a very common donor site for autogenous bone grafts. The aim of this retrospective study was to evaluate long-term morbidity of the donor site following chin bone graft harvesting. One to three years after grafting of local bone defects of the anterior maxilla with chin bone, 21 patients were recalled for objective assessment of any residual morbidity at the harvesting area. Morbidity as well as satisfaction of the patients were evaluated by a survey of the medical record, a mail-in questionnaire, and a standardized physical examination. The outcome of this study showed that there was good acceptance of the chin bone harvesting procedure. The objective morbidity was low, but subjectively almost half of the patients reported a changed (decreased) sensibility in the harvesting area. This subjective change in sensibility did not result in noteworthy complaints or discomfort by the patients, however. Although bone harvesting from the chin is generally considered as a good option for reconstruction of local bony defects, the patients should be informed about the potential hazard of a changed sensibility in the chin region.

Adolescent↗
PubMed2004

Unilateral posterior crossbite and chin deviation: is there a correlation?

A retrospective study evaluating the clinical discernment of chin deviations in general, and especially in relation to unilateral posterior crossbite (UPXB), was carried out to determine whether (1) there is a correlation between UPXB and clinically discernible chin deviation, (2) there are differences between the judgement of professional dental observers and laymen, (3) visual assessment of chin deviation compares well with computer-assisted assessment and (4) how large a chin deviation should be before it is noticed. The experimental group consisted of 72 patients (30 males and 42 females, average age 14.5 years) with a UPXB. A control group of 72 subjects without a UPXB was matched for age and sex. In addition, one computer-designed face was added with chin deviations of 0, 2, 4, 6 and 8 mm to the left. The full-face slides of all subjects were shown twice, with an interval of 2 weeks, to an audience of seven orthodontists, ten dental students and five laymen judging by eye. A computer-assisted assessment was carried out by one observer, in order to create a standardized comparison to visual scoring. Inter-observer examination of visual scoring showed moderate agreement (kappa = 0.48). When comparing the computer-assisted and visual scores, the intra-class correlation coefficient (ICC) was 0.87. There were no major differences between professional observers and laymen, although the latter gave significantly more responses in the direction opposite to the crossbite. In 70.3 per cent (on average) of the subjects with a crossbite, a deviation in the same direction as the crossbite was noticed visually. The majority of the observers observed a chin deviation of at least 4 mm.

Adolescent↗
PubMed2002

The effect of chin lift, jaw thrust, and continuous positive airway pressure on the size of the glottic opening and on stridor score in anesthetized, spontaneously breathing children.

UNLABELLED: Chin lift and jaw thrust are two common maneuvers used to improve the patency of the upper airway during general anesthesia. We investigated the effect of these maneuvers combined with continuous positive airway pressure (CPAP) on the size of glottic opening and on stridor score. Forty children, aged 2--9 yr, premedicated with midazolam and spontaneously breathing end-tidal 1% halothane and equal parts of nitrous oxide and oxygen, were studied. A flexible fiberoptic bronchoscope was placed via mask and one nostril to the level of the junction of the soft palate and oropharynx. Video recordings and simultaneous stridor scores were obtained during six conditions: 1) chin unsupported, 2) manual chin lift, 3) chin lift and CPAP 10 cm H(2)O, 4) repeat chin unsupported, 5) manual jaw thrust, and 6) jaw thrust and CPAP 10 cm H(2)O. Videos were analyzed to determine the percentage of glottic opening (POGO) score. POGO score increased (P < 0.05) in Conditions 2, 3, 5, and 6. With increasing POGO score there was a decrease in stridor score (P < 0.05). IMPLICATIONS: Chin lift and jaw thrust maneuvers combined with continuous positive airway pressure improve the view of the glottic opening as viewed by flexible nasal laryngoscopy and decrease stridor in anesthetized, spontaneously breathing children.

Anesthesia, General↗
PubMedDate not supplied

Nomograms for the sonographic measurement of the fetal philtrum and chin.

OBJECTIVE: To generate nomograms for the sonographic measurement of the fetal philtrum and chin during pregnancy. DESIGN: A prospective, cross-sectional study in normal singleton pregnancies. SUBJECTS: One hundred and fifty-three fetuses between 13 and 42 weeks of gestation were studied. METHODS: The philtrum was measured from the base of the columella to the upper lip. The chin was measured from the tip of the lower lip to the skin under the lower tip of the mandible. Predictive models were evaluated to generate graphic description of the 5th, 50th and 95th centiles for the fetal philtrum and chin. RESULTS: Fetal philtrum length increased with gestational age. The regression equation for the philtrum length (y) according to gestational age in weeks (x) is best predicted by the S-curve (Gompertz) model, as described by the following equation: y = exp(a + b/x), where a = 2.778577, and b = -23.476723 (R(2) = 85.3%, p < 0.0001). The fetal chin length increased with gestational age. The regression equation for the mean chin length (y) according to gestational age in weeks (x) is best predicted by the S-curve model as described in the following equation. y = exp(a + b/x), where a = 3.7922, b = -28.043, (R(2) = 89.0%, p < 0.0001). CONCLUSIONS: The nomograms generated in this study for the fetal philtrum and chin during pregnancy can be used in confirming subjective impression of facial dysmorphism.

Chin↗
PubMed2006

Mandibular biomechanics and development of the human chin.

The development of the chin, a feature unique to humans, suggests a close functional linkage between jaw biomechanics and symphyseal architecture. The present study tests the hypothesis that the presence of a chin changes strain patterns in the loaded mandible. Using an anatomically correct 3-D model of a dentate mandible derived from a CT scan image, we analyzed strain patterns during incisal and molar biting. We then constructed a second mandible, without a chin, by 'defeaturing' the first model. Strain patterns of the second model were then compared and contrasted to the first. Our main finding was that chinned and non-chinned mandibles follow closely concordant patterns of strain distribution. The results suggest that the development of the human chin is unrelated to the demands placed on the mandible during function.

Adaptation, Biological↗
PubMed1997

Chinrest pressure in violin playing: type of music, chin rest, and shoulder pad as possible mediators.

INTRODUCTION:: This study was conducted to determine if there are differences in pressure on a violin chin rest during performance due to changes in shoulder pads, chin rests, or pieces of music performed. It was also hypothesized that these differences would correlate with anthropometric measurements made of the subjects' necks and shoulders. METHODS::: A Novel EMED pad was used over the chin rest, containing 120 sensors, each one centimetre squared. The sampling rate was 50 Hz. A total of ten subjects, all professional violinists, performed excerpts from a Bruch violin concerto and a Handel sonata. Anthropometric measurements were made of the subjects' necks and shoulders. Each subject began by using his own violin with his usual shoulder pad and chin rest set-up, and then with the author's violin. Two different shoulder pads and three different chin rests were placed on the violin, in all possible combinations, for both pieces of music. This resulted in a total of fourteen conditions given in randomized order for each subject. Subjects were asked to give verbal feedback regarding the comfort and ease of playing of each shoulder pad and chin rest. Data was collected for three trials of each condition, and a mean for the three trials was obtained for each dependent variable. The five dependent variables were: peak pressure, maximum force, pressure/time integral and force/time integral, and total contact area. Intraclass coefficients of reliability were calculated for the dependent variables. Pearson's correlation coefficients were computed to determine if there were significant relationships between the five dependent variables and violin height, shoulder width, and neck length. RESULTS:: Pressure/time integral achieved the highest reliability with a coefficient of 0.9310, followed by peak pressure at 0.9152, force/time integral at 0.8817, maximum force at 0.8685, and total area at 0.8571. Multivariate analysis of variance detected significant differences in levels of pressure and force for the different conditions. Subsequent one-way ANOVAS andt -tests determined significantly less pressure on the Wolf chinrest as compared to the other chinrests. There were also reliable differences in pressure between the two pieces of music, with the Handel sonata excerpt showing significantly less pressure. There were no differences detected between the two shoulder pads. Significant relationships between neck length and shoulder width, and peak pressure, pressure/time integral, maximum force, force/time integral, and total contact area were found. A discussion of these results, and conclusions and implications for further study, are currently in progress.

Journal Article↗
PubMed1998

Individual growth in Class III malocclusions and its relationship to the chin cap effects.

Individual growth characteristics of the maxilla and the mandible in Class III malocclusions were investigated in terms of growth amount, growth direction, and timing of growth; chin cap effects were considered in the context of growth characteristics of the jaws. Longitudinal cephalograms of six untreated Japanese Class III subjects were used for the analysis of jaw growth from 8 to 14 years of age. The facial patterns were classified into the five groups with different effects of therapy by discriminant functions derived from our previous chin cap study. The results obtained were as follows: (1) Among the six subjects, inhibition of maxillary forward growth was found in four subjects at ages before the maximum pubertal growth in body height occurred, resulting from occlusal interference of anterior cross bite. The growth potential of the jaws appeared genetically normal, and the facial patterns were classified into groups in which chin caps have been found to be effective to some extent. (2) A subject with growth characteristics of strong mandibular downward growth was classified in a group showing backward growth of the mandible by chin caps. (3) One of the remaining sample showing the strongest mandibular forward growth was classified in a group where chin caps are not effective. (4) It was concluded that effects of chin cap therapy are closely related to growth characteristics of the mandible in Class III treatment.

Adolescent↗
PubMed1999

Effect of combined mouth closure and chin lift on upper airway dimensions during routine magnetic resonance imaging in pediatric patients sedated with propofol.

BACKGROUND: In pediatric patients, obstruction of the upper airway is a common problem during general anesthesia. Chin lift is a commonly used technique to improve upper airway patency. However, little is known about the mechanism underlying this technique. METHODS: The authors studied the effect of the chin lift maneuver on airway dimensions in 10 spontaneously breathing children (aged 2-11 yr) sedated with propofol during routine magnetic resonance imaging. The minimal anteroposterior and corresponding transverse diameters of the pharynx were determined at the levels of the soft palate, dorsum of the tongue, and tip of the epiglottis before and during the chin lift maneuver. Additionally, cross-sectional areas were calculated at these sites, including tracheal areas 2 cm below the glottic level. RESULTS: Minimal anteroposterior diameter of the pharynx increased significantly during chin lift at all three levels in all patients. The diameters of the soft palate, tongue, and epiglottis increased from 6.7+/-2.8 mm (SD) to 9.9+/-3.6 mm, from 9.6+/-3.6 mm to 16.5+/-3.1 mm, and from 4.6+/-2.5 mm to 13.1+/-2.8 mm, respectively. The corresponding transverse diameter of the pharynx also increased significantly at all three levels in all patients but without significant predominance. The diameters at the levels of the soft palate, tongue, and epiglottis increased from 15.8+/-5.1 mm to 22.8+/-4.5 mm, from 13.5+/-4.9 mm to 18.7+/-5.3 mm, and from 17.2+/-3.9 mm to 21.2+/-3.7 mm, respectively. Cross-sectional pharyngeal areas increased significantly at all levels (soft palate, from 0.88+/-0.58 cm2 to 1.79+/-0.82 cm2; tongue, from 1.15+/-0.45 cm2 to 2.99+/-1.30 cm2; epiglottis, from 1.17+/-0.70 cm2 to 3.04+/-0.99 cm2), including the subglottic level (from 0.44+/-0.15 cm2 to 0.50+/-0.14 cm2). CONCLUSIONS: This study shows that all children had a preserved upper airway at all measured sites during propofol sedation. Chin lift caused a widening of the entire pharyngeal airway that was most pronounced between the tip of the epiglottis and the posterior pharyngeal wall. In pediatric patients, chin lift may be used as a standard procedure during propofol sedation.

Child↗
PubMedDate not supplied

Mersilene mesh chin augmentation. A 14-year experience.

During the past 20 years, a variety of alloplastic materials have been introduced for chin augmentation. Mersilene mesh (Ethicon, Sommerville, NJ), introduced in 1950, demonstrates many qualities that make it an ideal implant. This article reviews the senior author's (S.W.P.) successful 14-year experience using Mersilene mesh chin implants. Between 1983 and 1997, 264 patients underwent chin implantation procedures. The results show a low rate of infection (0.8%) and displacement (1.5%). There were 14 temporary paresthesias and no cases of permanent anesthesia. There were no incidences of absorption, rejection, or extrusion. Mersilene provides a soft, natural appearance to the chin, and it continues to be our choice for chin implantation.

Adult↗
PubMed1984

Submental liposuction extraction with hard chin augmentation.

Liposuction techniques utilizing fat extraction sculpturing of the neck and simultaneous chin augmentation are described herein. In young persons, extraction is carried out in the submental areas. In older patients, who have diffuse fat accumulations and less skin tone, extraction includes the submental and submandibular areas, along with dry tunneling to the lateral borders of the sternocleidomastoid muscle and inferiorly to the suprasternal notch. When the skin tone is poor, with excessive redundancy, combined rhytidectomy with both open and closed liposuction is performed. With liposuction submental sculpturing , necessity for chin augmentation is critical to tauten the submental skin and to give a better neck-chin angle. Hard chin implants are preferred over the soft gelatinous types. We utilized a hard acrylic implant ( Rish ) in all cases. Results obtained by the dual approach of submental fat suction sculpturing and hard chin augmentation have been excellent.

Adipose Tissue↗
PubMed1992

Chin position in profile analysis. Comparison of techniques and introduction of the lower facial triangle.

Many patients undergoing rhinoplasty can benefit from chin augmentation, yielding a more balanced appearance. Preoperative facial analysis identifies patients with retrusive chins and suggests optimal chin position. Current profile analysis methods depend on subnasale position (Legan's angle) or require estimation of bony landmarks from soft-tissue photographs (Goode's alar crease perpendicular, Gonzalez-Ulloa's zero meridian, and Merrifield's Z-angle). We describe a technique for determining ideal chin position using soft-tissue landmarks. We compare this technique with Legan's, Goode's, Gonzalez-Ulloa's, and Merrifield's techniques in 35 women and conclude that this method provides accurate and rapid determination of ideal chin position.

Adult↗
PubMed1993

Chin-down posture effect on aspiration in dysphagic patients.

Use of the chin-down posture during swallowing has been reported to reduce the occurrence of aspiration in some dysphagic patients. This study measured four pharyngeal dimensions in 30 neurologically impaired patients who aspirated before the swallow because of a delay in triggering the pharyngeal swallow, 15 for whom the posture eliminated aspiration and 15 who aspirated despite the chin-down position. Patients who did not benefit from the posture were significantly younger and aspirated material from the pyriform sinus rather than the valleculae when the pharyngeal swallow was triggered. Changes in pharyngeal dimensions with the chin down were not significantly different for both patient groups, except for epiglottic angle, which increased significantly more in the group who continued to aspirate. Changes in pharyngeal dimensions with chin-neutral versus chin-down differed somewhat from those reported in a previous publication. Possible reasons for these differences are discussed.

Adult↗
PubMed1999

Osseous remodeling after inferior border osteotomy for chin augmentation: an indication for early surgery.

PURPOSE: This study investigated the relationship of age at surgery and type of fixation to the pattern and extent of bone remodeling associated with inferior border osteotomy for chin augmentation. PATIENTS AND METHODS: Four groups of patients with similar chin advancement were established by age at the time of surgery: younger than 15, 15 to 19, 20 to 24, and older than 39 years. Cephalometric radiographs for immediate preoperative, immediate postoperative, and at least 9 months postoperative times were traced, digitized, and superimposed. RESULTS: The pattern of osseous remodeling was similar for all age-groups. This consisted of resorption of the superior-buccal aspect of the distal segment, bone apposition on the buccal surface of the proximal segment, and modest resorption at pogonion (mean change, 1 mm or less). There was no significant difference in stability of the chin advancement between wire and rigid (screw) fixation. There was a marked difference in the symphysis thickness regeneration of the youngest group (92% of the original symphysis thickness) compared with the rest of the groups (< or =66%, P < .001). CONCLUSIONS: Minimal remodeling at pogonion occurs in all age-groups with both wire and rigid fixation. Regeneration of symphysis thickness is much more complete in patients younger than 15 years at the time of surgery. This is potentially important for early treatment of severe chin deficiency, because it permits additional advancement of the chin later in life, if necessary.

Adolescent↗