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PubMed1988

The chin.

The aesthetic aspects of the chin necessitate its evaluation in the context of the nose, mouth, and, to a lesser extent, the neck. Functional consideration must be given to the dental occlusion and the perioral muscular sphincter, and planning should acknowledge the sociologic implications of a strong versus a weak chin. After thorough skeletal and soft-tissue examination, the appropriate type of surgical intervention can be selected. Among the various procedures, chin implant remains the most commonly used, but the osteotomy offers the greatest flexibility, reliability, and potential for significant modification of chin form.

Chin↗
PubMed1995

The chin: skeletal and soft-tissue components.

The quantity of soft tissue overlying the symphysis menti affords an important attribute that can aid in determination of the correct surgical approach for optimal facial harmony. Xerograms of the facial profile of 100 patients with normal occlusion were analyzed by accepted radiographic cephalometric techniques. The relative contribution of skeletal structures and soft tissue of the chin was evaluated. All linear measurements were noted to be larger in males than in females, but in both groups, facial features were in proportion. In both males and females, the average thickness of the soft tissue overlying the symphysis menti progressively increased from the B point to midway between the B point and the pogonion. The soft tissue at the pogonion was thinner than at the B point. The soft tissue over the chin in males was significantly thicker than in females in all areas measured. When compared with patients over 60 years of age, the soft tissue at the B point was significantly thinner in patients 50 years of age and younger (p = 0.005), while the soft tissue at the pogonion was significantly thinner in patients 40 years of age and younger (p = 0.04). Pseudomacrogenia was noted in 6 percent of the patients, a diagnosis only possible with cephalometric analysis. An understanding of the relative contribution of the soft tissue to the chin can aid in the diagnosis and appropriate surgical management of chin incongruity. Furthermore, there is significant variation in skin thickness, which will influence the soft-tissue response to skeletal alteration. This has to be considered in planning a predictable surgical result.

Adolescent↗
PubMed1993

Changes in pharyngeal dimensions effected by chin tuck.

This study measured the pharyngeal dimensions of 30 subjects when their heads were in an upright neutral position and in the chin-tucked position. Two videoprints of lateral radiographic views of the oral cavity and pharynx were made for each subject: one with the head in neutral position and one with the chin tucked. A 1-cm metal ruler was taped at midline on the front of each patient's neck to account for radiographic magnification of the image. Three angles and three distance measures were made on each videoprint. With the chin tucked, a posterior shift of anterior pharyngeal structures occurred, narrowing the laryngeal entrance and the distance from epiglottis to the pharyngeal wall and the laryngeal entrance, while widening the angle of the epiglottis to the anterior tracheal wall. This posterior shift with the chin tucked improves airway protection. Other clinical implications of these changes in pharyngeal dimensions are discussed.

Adult↗
PubMed1999

Videomanometric analysis of supraglottic swallow, effortful swallow, and chin tuck in healthy volunteers.

Simultaneous videoradiography and solid-state manometry (videomanometry) was applied in eight healthy volunteers (four women, four men; age range 25-64 years, mean age 41 years) without swallowing problems. Three different swallowing techniques were tested; supraglottic swallow, effortful swallow, and chin tuck. Seven videoradiographic variables and six manometric variables were analyzed. The supraglottic swallowing technique did not differ significantly from that of the control swallows. The effortful swallow had a significantly (p = 0.0001) reduced hyoid-mandibular distance preswallow due to an elevation of the hyoid and the larynx, which caused a significantly (p = 0.007) reduced maximal hyoid movement and a significantly (p = 0.009) reduced laryngeal elevation during swallow. The chin tuck swallow had a significantly (p = 0. 001) reduced laryngohyoid distance and also a significantly (p = 0. 004) reduced hyoid-mandibular distance. The chin tuck swallow also displayed significantly (p = 0.003) weaker pharyngeal contractions. Videomanometry allows for analysis of bolus transport, movement of anatomical structures, and measurement of intraluminal pressures. These variables are important when evaluating swallowing techniques. In the present study, we made a few observations that never have been reported before. When healthy volunteers performed supraglottic swallow, they performed the technique somewhat differently. Therefore, we assume dysphagic patients would need a substantial period of training to perform a technique efficiently. Chin tuck could impair protection of the airways in dysphagic patients with weak pharyngeal constrictor muscles.

Adult↗
PubMed1984

A roentgenocephalometric study of skeletal changes during and after chin cup treatment.

Skeletal changes before and during chin cup treatment and the stability of results after treatment were studied. Materials consisted of longitudinal lateral cephalometric roentgenograms of twenty-six Japanese females with skeletal Class III malocclusion treated with the chin cup. Treatment was started when patients were 6 to 9 years of age. Annual changes in linear and angular measurements before, during, and after treatment were analyzed statistically. The results were as follows: (1) There was some reduction in the amount of expected growth increment in the mandible; a change in mandibular form and distal displacement of the mandible took place during treatment. (2) There was no obvious change in the cranium and maxilla during treatment. (3) Neither acceleration nor restraint of expected growth increment was found after treatment. The exception was forward displacement of the mandible during the first year after removal of the chin cup. To illustrate these results, the skeletal changes of one individual Japanese Class III female during and after chin cup treatment were analyzed with the use of fifteen parameters indicating area ratios, linear ratios, and angles. The control sample consisting of 426 nontreated Japanese females with skeletal Class III malocclusion was observed, varying between 3 years and 30 years of age. The growth in this case showed a trend similar to that of the control sample for the observation period, but it was redirected from the expected natural growth for the treatment period.

Adolescent↗
PubMed1985

The effects of chin cup therapy on the mandible: a longitudinal study.

This study was conducted to evaluate the effects of chin cup therapy on the mandible and its dentition in persons with skeletal Class III malocclusion. The patients selected for this study were Japanese females treated with the extraoral chin cup appliance. Both the control and treatment samples were obtained from Japanese Universities where the longitudinal data were gathered. Lateral cephalometric radiographs were taken on the average of every 6 months for the treatment group and every year for the control group. Ten treated patients and seven control patients were studied. The duration of chin cup therapy was variable but averaged 3 years 1 month. The cephalograms were digitized on an electronic screen, and a cephalometric analysis was recorded from a computer program. The rate change values were then compared with those of the control group to yield a comparison of changes in mandibular growth rate, direction, and pattern in the treatment group. Active and posttreatment effects were evaluated. All measurements for the rate of change of absolute mandibular length were reduced by 60% to 68% from the control rate of growth during therapy. The mandible exhibited less downward displacement relative to cranial base during treatment. The mandibular plane angle and the gonial angle closed with growth in the Class III control sample but were variable in the treatment group. The skeletal profile was improved with treatment. This study indicates that the chin cup may be a viable mode of treatment for the preadolescent and adolescent mandibular prognathism patients.

Adolescent↗
PubMed1985

Chin rub CRs are elicited by flavors associated with apomorphine, scopolamine, methscopolamine, physostigmine and neostigmine.

Three experiments were conducted in order to determine the pattern of behavioral conditioned responses (CRs) elicited by flavors paired with each of various drugs which effectively establish avoidance of a flavored solution. Each of the drugs employed supported both chin rub CRs and avoidance of a flavored solution. Experiment 1 employed apomorphine, a classic emetic agent which pharmacologically acts as a dopaminergic agonist. Experiment 2 and 3 employed cholinergic agonists and antagonists which were either peripherally or both peripherally and centrally acting agents. The results suggest that chin rub CRs may be produced by means of the activation of a system which is peripheral to the CNS. Furthermore, flavor avoidance produced by drugs which support chin rub CRs may be mediated by a shift in the hedonic rating of the flavored solution; whereas, flavor avoidance produced by drugs which do not support chin rub CRs is probably mediated by a mechanism other than a hedonic shift.

Animals↗
PubMed1998

Clinical evaluation of temporomandibular joint disorders (TMD) in patients treated with chin cup.

The purpose of this manuscript was twofold: (1) to provide more information on the incidence of temporomandibular joint disorders (TMD) in chin cup-treated patients during and after active treatment; and (2) to evaluate results of functional analysis for one orthodontically treated chin cup patient with temporomandibular joint (TMJ) pain and difficulty of maximum mouth opening. Eighty-six out of a total of 160 chin cup patients responded to our questionnaire and were checked for pain, clicking, and maximum mouth opening. Twenty-eight of the chin cup subjects showed one or more symptom(s) of TMD. Spontaneous pain was found most often during active treatment but clicking (sound) occurred more often during the retention phase. One retreated patient showed remarkable improvement of TMD symptoms.

Adolescent↗
PubMed2006

Numb chin syndrome--a reflection of systemic malignancy.

BACKGROUND: Numb chin is an uncommon underappreciated though well documented neurological manifestation of metastatic malignancy. CASE PRESENTATION: A 50-year-old patient presented with right numb chin for few days. No dental cause was found. He later developed generalized vague symptoms. In few weeks his liver and renal functions deteriorated. Blood picture showed leucoerythroblastic picture. CT scan and bone marrow biopsy done at this stage revealed underlying high grade lymphoblastic lymphoma. He went into multiorgan failure, requiring ventilatory support and death within a short period. CONCLUSION: Numb Chin is a syndrome which initially presents with unilateral numbness or orofacial pain in the distribution of the inferior alveolar nerve and its branches with an underlying systemic malignancy. We emphasise that physicians and dentists should consider metastatic cancer in any patient who presents with chin or jaw numbness where no other obvious cause for their complaint is found.

Journal Article↗
PubMed1980

Effects of Chinese herb, Huang Chin (Scutellaria baicalensis George) on thermoregulation in rats.

Intragastric administration of a Chinese herb, Huang Chin extract (Scutellaria baicalensis George), produced a dose-dependent fall in rectal temperature in conscious rats in a room the temperature of which was 22 degrees C or below. The hypothermia in response to Huang Chin application was brought about solely by cutaneous vasodilatation (as estimated by an increase in cutaneous temperatures). There were no changes in either metabolic heat production or respiratory evaporative heat loss. However, in the heat (29 degrees C), Huang Chin administration produced no changes in rectal temperature or other thermoregulatory responses. The data indicate that Huang Chin extract produces peripheral vasodilatation which leads to a hypothermia in conscious rats.

Animals↗
PubMed1995

CHINs: making the important decisions.

Community health information networks (CHINs) are an evolving concept. In their most basic form, CHINs provide a structure for sharing financial and clinical information among a defined group of entities. However, several key decisions affect how a CHIN will function. Among those decisions are what "community" will be included, what technical infrastructure to use, what organization or group of organizations will lead the CHIN development effort, what types of information will be shared, and how to safe-guard confidentiality.

Clinical Medicine↗
PubMed1989

[Individual growth study of the effects of chin cap force to the mandible].

This study was undertaken to investigate a certain regulation of the chin cap force to a growing human mandible, especially with regard to the effect on the growth amount and timing by means of allometric relation between stature and craniofacial complex. Materials were consisted of roentgencephalograms which had been taken from fifteen Japanese females with skeletal class III malocclusion and records of time length of chin cap use and stature. The results were as follows: 1. Chin cap had a great influence on mandible during the preadolescent and adolescent periods (P less than 0.01). 2. What was most influenced by orthopedic force was intercondylar width, followed by mandibular length, intergonial width, mandibular body length, and ramus height. 3. Restraint of growth was found in mandibular length, mandibular body length, and ramus height, but on the other hand acceleration of growth in intercondylar width and intergonial width was also found. In conclusion, it would be possible to say that if it is used propertly, chin cap therapy can be effective within certain limits for skeletal class III malocclusions in view of restraint and acceleration of mandibular growth.

Cephalometry↗
PubMed1996

CHINs in the context of an evolving health care system.

Community Health Information Network (CHIN) developments have slowed, due to the chaotic change in the health care system and stakeholders' attendant short-sighted focus. CHINs are a long-term investment that is necessary for the health care system's evolution to maturity. Several arenas of essential CHIN activity are given that would be characteristic of a mature, goal-directed health care system Lack of enterprise-wide computer-based patient record systems is a major barrier. Even in the short term, however, trends and incentives exist that are likely to push stakeholders toward CHIN development. Some of these trends include changes in organizational structure and political pressures. Practical incentives include the need for stakeholder cooperation to achieve healthy communities, the prospects for telemedicine, and the demand for greater quality assurance.

Community Networks↗
PubMed2006

Two new families with hereditary essential chin myoclonus: clinical features, neurophysiological findings and treatment.

Hereditary essential chin myoclonus (HECM) is a rare movement disorder characterised by involuntary and irregular twitches of the chin. It can be considered a benign, focal variant of hereditary essential myoclonus. We studied two families that had several members suffering from HECM. Both families showed an autosomal dominant transmission with incomplete penetrance. Extensive neurophysiological studies were carried out on three patients. The results confirmed the myoclonic nature of phenotypical appearance and allowed identification of the subcortical origin of the myoclonus. The neurophysiological mechanisms underlying HECM are still unknown. It is supposed that pontine reticular formation, not controlled by superior centers, may be responsible of an abnormal activation of motor neurons innervating mentalis muscle. We treated three patients with periodic injections of botulinum toxin; a complete disappearance of chin myoclonus improved their quality of life.

Adolescent↗
PubMed1982

Interocclusal distance measurement comparing chin and tooth reference points.

In a group of nine dentate students with a mean age of 23.1 years, a comparison of their interocclusal distances was determined using tooth and chin reference points. This determination was made with two reference LEDs, one attached to a lower tooth and the other attached to a point on the chin. These two LEDs were registered simultaneously using the Selspot system and analyzed with the use of a computer. Three different methods were used to establish the interocclusal distance: a phonetic method, a relaxation method, and a swallowing method. Independent of the method selected, there was a greater interocclusal distance recorded by the tooth-attached reference LED. This study indicates that, in the clinical determination of interocclusal distance, where a chin reference is used the dentist should be aware of this difference--especially when lip activity is involved.

Adult↗
PubMed1982

Chin trauma: a clue to associated mandibular and cervical spine injury.

Chin trauma, mandibular fracture, and cervical spine injury are often progressive components of a single injury pattern. Knowledge of a commonly occurring sequence of damage in patients who have sustained minor head trauma helps to minimize diagnostic omissions and provides a rational basis for deciding how extensive the patient's evaluation should be. Chin laceration associated with underlying skeletal damage has been described previously, but its diagnostic significance seldom has been appreciated. This report describes representative patients with fractures of the cervical spine and of the mandible secondary to chin trauma and suggests a protocol for efficient diagnosis.

Adult↗
PubMed1991

Bone resorption, stability, and soft-tissue changes following large chin advancements.

Large advancement genioplasties were performed in 10 patients (mean advancement, 11.7 mm) by horizontal osteotomy of the inferior border of the mandible, with preservation of a musculoperiosteal pedicle to the advanced genial segment. Preoperative, immediate postoperative, and long-term follow-up lateral cephalometric radiographs were retrospectively analyzed to evaluate the osseous and soft-tissue changes of the chin. After a mean follow-up period of 15 months, 76% of the initial advancement was preserved, representing 24% osseous resorption. The enveloping soft tissues of the chin followed the bony movement in a ratio of 1:0.88. Horizontal osteotomy of the inferior border of the mandible was a relatively stable procedure when used for large chin advancements. The broadcast possible musculoperiosteal pedicle should remain attached to the advanced genial segment to minimize osseous resorption and to achieve more predictable soft-tissue changes.

Adolescent↗
PubMed2005

Evaluation and treatment of deformities of the chin.

Chin deformities present commonly to the facial plastic surgeon. Proper evaluation of the face is essential to allow the surgeon to counsel the patient properly regarding optimal management of chin deformities. This article reviews such analysis and discusses treatment modalities, including both the use of chin implants and osseous genioplasty.

Chin↗