Biomedical subjects

M G Hans

Publications and source records attributed to M G Hans.

25 records · Page 2Linked to original sources

PubMed1994

Upright and supine cephalometric evaluation of obstructive sleep apnea syndrome and snoring subjects.

Specific craniofacial characteristics are reported to occur with obstructive sleep apnea syndrome (OSAS). The purpose of this study was to determine whether craniofacial morphology differs between subjects with OSAS and heavy snorers, and to investigate how change in posture from upright to lying down affects the upper airway passage. Lateral head radiographs of ten persons diagnosed with OSAS(AHI > 50) and ten snorers matched for age, height and weight without any history of daytime sleepiness, doctor-diagnosed OSAS, and no evidence of significant desaturation on overnight oximetry were obtained in both upright seated and awake supine positions. The posterior superior pharyngeal space in both the OSAS and snorers was reduced when changing from upright to supine posture (p < or = 0.05). Significant differences in cranial base alignment, ramus width relative to the middle-cranial fossa, position of the maxilla relative to the cranial base in the seated position (P < or = 0.01) were noted between subjects with OSAS and subjects with snoring and less severe apnea. In addition, differences in the posterior superior pharyngeal space, tongue length, tongue to intermaxillary area ratio and hyoid position (p < or = 0.05) were demonstrated both in the upright and in the supine positions (p < or = 0.05) in the OSAS compared to the snoring group. These results suggest that anatomic factors may predispose some snorers to develop OSAS. Measurements made from awake supine position lateral head radiographs revealed no additional differences between OSAS and snoring subjects when compared to measurements made on radiographs taken in the upright position.

Cephalometry↗

PubMed1994

Cephalometric evaluation of two treatment strategies for deep overbite correction.

This study compared the cephalometric changes achieved using fixed versus removable appliances to correct deep overbite in growing patients. Forty-five patients treated with cervical headgear/tandem mechanics and 50 patients treated with a bionator appliance were compared with 95 control subjects from the Bolton Study. Treatment differences were determined using a cephalometric analysis that isolated vertical changes in overbite as the composite result of 6 variables: maxillary skeletal change, tipping of the upper incisors, bodily movement of the upper incisors, mandibular skeletal change, lower incisor tipping, and bodily movement of the lower incisors. The interaction of treatment type with facial type was also examined. In the headgear/tandem group, overbite was corrected by a combination of intrusion of the upper incisors and increases in mandibular skeletal change. Treatment with the bionator resulted in correction of the overbite by relative intrusion of the upper and lower incisors and increases in mandibular skeletal change. There were no significant interactions with facial type in the headgear group. Gonial angle and lower tipping were influenced by facial type in the bionator group. These results demonstrate that fixed and removable appliances produce both qualitative and quantitative differences in treatment response. Further studies are planned to create a rational decision tree that can be used to aid the clinician in the differential diagnosis and treatment of deep overbite.

Activator Appliances↗

PubMed1994

The prevalence and patterns of dental caries in Labrador Inuit youth.

OBJECTIVES: This study was undertaken to examine the prevalence of dental caries in Inuit (Eskimo) youth aged 5-22 years. METHODS: Both tooth-oriented indices and child-oriented caries patterns were recorded in a field study conducted in 1991 in Nain and Hopedale, Northern Labrador. Seventy-eight percent (N = 347) of all school-children in these two locations were examined by a single examiner. RESULTS: Three percent of the population were caries free and 88 percent of those with caries experience had untreated dental decay. The mean combined dmft and DMFT per child for all ages was 6.85, while the mean combined dmfs and DMFS was 15.72. About 38 percent of subjects had pit and fissure caries; 2 percent had hypoplastic lesions; 4 percent had faciolingual caries; 31 percent had molar-approximal caries and 22 percent had faciolingual and molar-approximal caries, the most destructive caries pattern. About 68 percent of the 5-6-year-olds and 26 percent of the 15-22-year-olds experienced the most destructive pattern of decay in their primary and permanent dentitions, respectively. CONCLUSIONS: Preventive measures should start well before the age of 5 years. Describing caries patterns according to the dentition type complemented the traditional indices.

Adolescent↗

PubMed1994

Growth patterns of Labrador Inuit youth: II. Skeletal age.

Few studies have been conducted on skeletal maturity of circumpolar populations despite its importance as background knowledge to orthopedic and orthodontic procedures or for other medical problems involving endocrine disturbances. The purpose of this study was to compare skeletal age with chronological age of Labrador Inuit youth aged between 5-18 years and to compare these results with data from a national survey of United States youth. The sample included 32% (n = 100) of the Inuit youth living in Nain, Labrador, Canada (Male = 41, female = 59). Hand wrist radiographs, collected during a field study in 1991, were used to estimate bone age using the Greulich and Pyle bone specific method. The mean relative Inuit skeletal ages increased almost consistently with chronological age but showed considerable individual variation as shown by the 95% confidence intervals. The pattern of growth of skeletal vs chronological age was similar to the National Center for Health Statistics data but the tempo was slower. The Z-scores for mean male relative bone ages ranged from -0.7 to -1.9 and for females from -0.6 to -1.4. The results indicated that Inuit males started to reach adult skeletal maturity levels by the chronological age of 17 years 9 months, and Inuit females by 15 years 8 months. Generally, Inuit skeletal ages were delayed by 10-24 months behind the reference atlas skeletal ages and 9-22 months behind the Inuit chronological ages.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

A comparison of clinical examination, history, and magnetic resonance imaging for identifying orthodontic patients with temporomandibular joint disorders.

The temporomandibular joint (TMJ) status of 51 juvenile orthodontic patients was assessed with magnetic resonance imaging (MRI), clinical examination, and questionnaire data. The results of this study demonstrated that the prevalence of anterior displacement of the meniscus was 11.8% (6 of 51) as assessed by MRI. Clicking or pain in the TMJ area was found in 9.8% (5 of 51) of the subjects by clinical exam, and 19.8% (10 of 51) of the subjects had a history of pain or clicking of the TMJ. Three subjects had a positive MRI and a negative history and clinical examination. However, all subjects with positive MRI findings had a history of other risk factors known to be associated with TMJ internal derangement (TMJ-ID). Therefore practitioners should use a history form and a clinical examination technique that includes a broad range of signs and symptoms of temporomandibular disorders (TMD) to identify patients who may have abnormal condyle disk relationships and be at risk for TMD. Clicking and pain in the TMJ helped identify only one half of the patients with abnormal condyle-disk relationships in this study population. Future cephalometric studies will monitor the effects of abnormal condyle disk relationships on facial growth during orthodontic treatment.

Adolescent↗

PubMed1992

Class I and Class III malocclusion sub-groupings related to headform type.

Different headform types establish different lines of craniofacial growth resulting in anatomic sub-groupings of Classes I, II, and III with characteristic morphologic features. Several key basicranial and facial relationships are involved, with the nasal region particularly significant in group distinctions.

Adolescent↗

PubMed1992

MR imaging of the juvenile temporomandibular joint: preliminary report.

Thirty-two children were evaluated by means of medical history and physical examination for signs and symptoms of internal derangement (ID) of the temporomandibular joint (TMJ) and mandibular dysfunction. These children also underwent magnetic resonance (MR) imaging of the TMJs. The study was double blind. At clinical examination, 19 patients (59%) had at least one positive finding of ID of the TMJ and/or mandibular dysfunction. MR images of the TMJ obtained in 60 of the 64 TMJs demonstrated 57 normal joints (95%) and three abnormal joints (5%). Two of these three joints had a mild anterior-lateral disk displacement, and one joint had an anterior dislocated disk. There were no false-positive MR examinations. MR imaging failed to depict abnormalities in 16 patients who had positive findings at history and/or physical examination. Although MR imaging may fail to depict ID of the TMJ in some patients, clinical techniques commonly used in population surveys probably overstate the prevalence of ID of the TMJ in children.

Adolescent↗