Biomedical subjects

K W Vig

Publications and source records attributed to K W Vig.

At least 19 recordsLinked to original sources

PubMed2001

A comparison of cranial base growth in Class I and Class II skeletal patterns.

The purpose of this retrospective longitudinal study was to compare 7 cephalometric measurements of the cranial base in subjects with Class I and Class II skeletal patterns at ages 1 month, 2 years, and 14 years. A sample of 22 Class I and 21 Class II subjects was selected; the inclusion criteria were overjet, ANB, and Harvold unit difference. Analyses of head circumference, crown-rump length, and weight revealed no significant (P >.15) differences between the Class I and Class II infant subjects at the initial age (1 month). One angular and 6 linear measurements were first compared with a multivariate analysis of variance, which revealed significant effects for age (P <.0001) and the age by skeletal pattern interaction (P =.0266) but not for skeletal pattern (P =.3705). Analyses of variance showed significant (P <.0001) age effects for each of the cephalometric variables but no significant skeletal pattern effects (P >.10). The anterior cranial base measurement of nasion to sphenoethmoidal suture was the only variable found to have a significant age by skeletal pattern interaction (P <.006), which revealed a difference in the timing of its growth spurt that occurred between 1 month and 2 years in the Class I subjects and between 2 years and 14 years in the Class II subjects. There were no significant differences between the skeletal classes at any of the 3 ages evaluated. Conclusions from this study indicate that cranial base growth patterns are similar for Class I and Class II subjects and that the premise of a more obtuse "saddle angle" or cranial base angle in Class II skeletal patterns was not supported.

Adolescent↗

PubMed2001

A comparison of the reliability and validity of 3 occlusal indexes of orthodontic treatment need.

Several occlusal indexes are currently used to ascertain eligibility for orthodontic treatment. A comparison of 3 indexes of orthodontic treatment need was made with the consensus opinion of a panel of 15 experienced orthodontists. Sets of study casts (170) representing the full spectrum of malocclusions were selected. An examiner, calibrated in the Dental Aesthetic Index, the Handicapping Labiolingual Deviation with the California Modification, and the Index of Orthodontic Treatment Need, scored the casts. The panel of orthodontists individually rated the same casts for their degree of orthodontic treatment need. The mean rating of the panel on the need for treatment was used as the gold standard for evaluating the validity of the indexes. Intrarater and interrater reliability was high (kappa > 0.8). Overall accuracy of the indexes, as reflected in area under receiver-operating characteristic curves, was also high: Dental Aesthetic Index, 95%; Handicapping Labiolingual Deviation with the California Modification, 94%; and Index of Orthodontic Treatment Need, 98%. Cutoff points for the indexes that resulted in the closest agreement with the gold standard differed from the published cutoff points for the indexes. The indexes appear to be valid measures of treatment need as perceived by orthodontists. The published cutoff points for the indexes were more conservative in assigning patients for treatment than a panel of orthodontists. However, adjusting the cutoff points moved all 3 indexes into close agreement with the experts.

California↗

PubMed2001

Measuring orthodontic treatment satisfaction: questionnaire development and preliminary validation.

OBJECTIVES: The aims of this study were to develop a reliable self-report measure of consumer satisfaction with orthodontic treatment, and to preliminarily assess its validity. METHOD: Transcripts of qualitative interviews with patients, their parents, and practicing orthodontists together with items from existing dental satisfaction questionnaires were used to develop a pool of 41 items assessing satisfaction with various aspects of orthodontic care. These items were paired with five-point Likert scales (1 = strongly disagree, 5 = strongly agree) and were administered to 299 parents of children who had completed orthodontic treatment at two university-based clinics. RESULTS: Factor analyses and reliability analyses identified three main subscales with high reliabilities: 13 items assessing satisfaction with treatment process (Cronbach's alpha = .92), seven items assessing satisfaction with psychosocial effects of treatment (Cronbach's alpha = .87), and five items assessing satisfaction with overall treatment outcome (Cronbach's alpha = .79). Relationships among these three subscales and pre- and posttreatment variables were examined in a subset of 86 parents/patients. Forward stepwise regression with backward overlook revealed no significant relationships between any satisfaction subscale and demographic variables. Posttreatment overjet was inversely related to parental satisfaction with orthodontic treatment process (R2 = .13; P < .001), and parent satisfaction with treatment outcome (R2 = .28; P < .0001). Improvement in esthetics as measured by improvement in IOTN Aesthetic Component scores was positively related to satisfaction with psychosocial outcomes (R2 = .28; P < .0001). CONCLUSIONS: The present instrument is reliable and can be used to assess three dimensions of parental satisfaction with their child's orthodontic treatment. Relationships between visible orthodontic outcome variables and parent satisfaction provide preliminary validity support for the instrument.

Adolescent↗

PubMed2000

Facial growth and management of orthodontic problems.

This article enables pediatricians to identify and understand the implications of common facial growth problems in children and adolescents. Problems with facial growth can result in aesthetic and functional concerns. Using a simple method of clinical evaluation, pediatricians can identify facial growth problems in the anteroposterior, vertical, and transverse dimensions. These problems can then be referred for evaluation and treatment by various means. Because facial growth is the result of the interaction of genetic and environmental factors (some of which are functional), growth modification may be a possibility. Some problems may be camouflaged or treated by combined surgical and orthodontic means. Continued growth in early adulthood may enhance or detract from treatment results obtained in childhood or adolescence. These dynamic properties of the face make management of facial growth challenging but generally rewarding and successful because of substantial aesthetic and functional improvements.

Adolescent↗

PubMed2000

Cephalometric variables as predictors of Class II treatment outcome.

Cephalometric analysis of skeletodental features is accepted as an integral part of orthodontic diagnosis and treatment planning. This assumes that diagnostic cephalometric variables affect prognosis and thus help reduce malocclusion severity, which is the aim of orthodontic treatment. The aim of this study was to assess the predictive value of 41 commonly used cephalometric parameters with regard to pretreatment severity and treatment outcomes. Pretreatment severity was assessed by using the Peer Assessment Rating (PAR) occlusal index, an instrument that has been shown to be valid and reliable. Treatment outcomes consisted of (1) posttreatment malocclusion severity (post-PAR), (2) relative improvement (percent PAR reduction), and (3) treatment duration. Complete records, including cephalograms, of 223 treated Class II cases were analyzed by means of separate multiple linear regression models. Each of the outcome variables and the pretreatment severity served as the respective dependent variables, and the cephalometric parameters served as the independent or predictor variables. The cephalometric parameters explained 39.2% of the pretreatment severity variance, 17. 9% of posttreatment severity variance, 15.7% of relative treatment improvement variance, and 20.0% of treatment duration variance.

Analysis of Variance↗

PubMed1999

Developing outcome measures in orthodontics that reflect patient and provider values.

During the past decade, emphasis in orthodontics has been directed toward the development of outcome measures from both the patient and clinician perspectives. New methodological standards of rigor have been introduced into research design to eliminate bias and test well-defined questions. Sample size calculations and established exclusion and inclusion criteria define sample populations and the ability to statistically accept or reject hypothesis-driven clinical studies. Although advances in our understanding of evidence-based medicine and dentistry from the provider perspective have been productive, the emerging value placed on patient perspective has not been as forthcoming. The emphasis placed on patient-oriented clinical research has resulted in new constructs of surveys and questionnaires in which the items are derived and tested from the patient's point of view. Because orthodontics is a condition without the natural history of a disease process for which no intervention has predictable consequences, new strategies have been developed to estimate need and demand for orthodontic treatment. Studies to measure seekers and nonseekers of orthodontic treatment are reported, as well as sex and cross-cultural issues in the use of established process and outcome measures. The design of clinical studies is discussed in the context of future directions for clinical research, and the usefulness of the information generated will directly relate to providing patients with the necessary information to make decisions and hence knowledgeably give informed consent for treatment interventions.

Clinical Trials as Topic↗

PubMed1999

Dentofacial morphology and upper respiratory function in 8-10-year-old children.

OBJECTIVES: The aim of this preliminary study was to assess the nature of associations between selected dentofacial morphological variables and respiratory mode as measured by percent nasality (%N) as part of an ongoing longitudinal study. DESIGN: Cross-sectional cohort study. SETTING AND SAMPLE POPULATION: The Pediatric Clinical Study Center, Children's Hospital, Columbus, OH. Ninety-eight normal children were tested. EXPERIMENTAL VARIABLE: Normal variation in %N. OUTCOME MEASURE: Selected dentofacial morphological variables including total and lower anterior face heights, face width, and palatal arch width and %N were estimated. RESULTS: Small associations between morphologic features and respiratory mode were found, but none were statistically significant. CONCLUSION: No evidence exists for the classic association between 'mouth breathing' and the stereotype of the 'adenoid facies'.

Airway Resistance↗

PubMed1999

Alveolar bone grafts: the surgical/orthodontic management of the cleft maxilla.

The purpose of this paper is to discuss the management of the cleft maxilla with emphasis on the controversies concerning the decisions which a cleft palate team makes with limited evidence but strong beliefs in the anticipated outcomes. The orthodontist and the surgeon need to collaborate in determining the timing and sequencing of alveolar bone grafting. Currently the emphasis on secondary bone grafting has superseded primary bone grafting in its effectiveness and efficiency. Contemporary management of infants born with clefts of the lip and palate is to delay bone grafting until the early mixed dentition stage of dental development with the optimal timing being related to the development of the unerupted permanent canine. In the management of patients with cleft palate, the surgeon and the orthodontist need to evaluate the mixed dentition stage of dental development to determine the optimum timing of treatment to coincide with the most favourable eruption of the maxillary canine or the lateral incisor when this tooth is on the distal side of the cleft. The issues which have led to controversy relate to (i) the age at which alveolar bone grafting should be performed, (ii) the type of bone graft and the site from which the donor bone will be harvested and (iii) the timing of the maxillary expansion and whether this should be performed before or after the alveolar bone graft is placed. A review of contemporary management of the palatal and alveolar cleft is discussed and illustrated in unilateral and bilateral clefts of the maxilla.

Age Factors↗

PubMed1998

Nasal obstruction and facial growth: the strength of evidence for clinical assumptions.

The orthodontic relevance of nasorespiratory obstruction and its effect on facial growth continues to be debated after almost a century of controversy. The continuing interest in nasal obstruction is fueled by strong convictions, weak evidence, and the prevailing uncertainty of cause and effect relationships that exist. The essence of any debate is to provide opposing evidence from which a majority vote is obtained. Political issues may be appropriately resolved by such means as a majority vote. Scientific issues, however, can only be resolved by data and appropriately structured hypotheses put to the test. One of the problems in debating nasorespiratory obstruction and facial growth is the inability to provide unequivocal answers to such issues as: How much nasal obstruction is clinically significant? At what age is the onset critical and for how long does it have to exist before an effect on facial growth can be expected? To provide unequivocal answers, clinical studies need to be designed to identify and quantify the degree of nasorespiratory obstruction and compare individuals for any clinically relevant differences. The purpose of this article is to review the available evidence. If both data and untested popular beliefs are subjected to the same rigorous criteria, indications for the orthodontic management of patients with nasorespiratory obstruction may gain a more rational approach to treatment recommendations.

Adolescent↗

PubMed1998

Orthodontic process and outcome: efficacy studies--strategies for developing process and outcome measures: a new era in orthodontics.

The development of process and outcome measures in orthodontics lends itself to retrospective clinical studies. Once valid and reliable measures have been tested, prospective studies may utilize these measures to assess the quality of orthodontic treatment outcome and the duration and process of treatment. The findings from two retrospective studies comparing the quality of outcome using the peer assessment rating (PAR) occlusal index and duration of treatment are reported. Class I and Class II treatment comparisons indicate the duration of treatment time is increased on average 5 months in Class II, division 1 patients. In the second study, the effect of extraction/non-extraction treatment in a sample that included all types of malocclusion indicates that, on average, treatment time is increased by approximately 5 months when extractions are included as part of the orthodontic treatment plan.

Analysis of Variance↗

PubMed1998

Distraction osteogenesis of the mandible with a modified intraoral appliance: a pilot study in miniature pigs.

The purpose of this study was to evaluate an intraoral, nontooth-borne, submucosal distraction appliance in the pig mandible from a clinical, radiographic, and histologic perspective. Intraoral distraction appliances were fabricated, tested for strength, and then adapted and rigidly fixated to the mandibles of three growing miniature Yucatan pigs. A bicortical osteotomy was performed on the right side of the mandible, and a buccal and lingual corticotomy on the left. Two amalgam markers were placed on each side of the osteotomy/corticotomy sites as references. Measurements were taken to evaluate the length and vector of the distraction site, and radiographs were obtained perioperatively. After a latency period of 5 days, distraction was commenced and continued for 13 days at a rate of 1 mm/day. Clinical evidence of distraction was apparent in all cases, with resulting Class III skeletal deformities. Distraction progressed further for the corticotomy sides than the osteotomy sides because of distraction device failure. Radiographic examination revealed increased bone density at the periphery of the distracted callus, with less density apparent centrally. Histologic examination showed fibrous connective tissue in the center of the callus, with cartilage and osteoid formation at the periphery. Bone formation was parallel to the vectors of distraction in all cases. This study confirms that the use of a modified intraoral appliance for distraction osteogenesis is feasible. Use of this device overcomes many of the problems associated with extraoral devices and may have clinical applications.

Animals↗

PubMed1997

A validation study of three indexes of orthodontic treatment need in the United States.

The purpose of this study was to compare the reliability and validity of three occlusal indexes of orthodontic treatment need in predicting the opinion of treatment need of a panel of 18 orthodontists. A set of 160 study casts representing all types of malocclusion was used. The casts were scored with the following occlusal indexes: the Index of Orthodontic Treatment Need (IOTN), the Handicapping Labio-Lingual Deviations index (HLD), and the Handicapping Malocclusion Assessment Record (HMAR modified). The diagnostic accuracy or validity of each index was calculated using the mean opinion of the orthodontic raters as a "gold standard". Receiver Operating Characteristic curves were plotted for each index. The overall diagnostic accuracy, as determined by percent area under the curve, was similar for each index: IOTN 98.6%; HLD 96.1%; HMAR 96.6%. The score optimizing the sensitivity and specificity relationship for each index was as follows: IOTN (dental health component) 4; HLD 13; HMAR 12. These results indicate that the three occlusal indexes provided valuable information for determining orthodontic treatment need.

Esthetics, Dental↗

PubMed1995

The validation of the Peer Assessment Rating index for malocclusion severity and treatment difficulty.

The Peer Assessment Rating (PAR) index is a British occlusal index that measures the severity of dental malocclusion and has been used in several investigations that have evaluated the effectiveness of orthodontic treatment provision in Europe. As part of its development, the PAR index was validated for malocclusion severity, by using the opinions of a panel of 74 dentists and orthodontists. The present investigation was carried out to validate the PAR index, by using the opinion of an American panel of orthodontists. Eleven orthodontists examined a sample of 200 sets of study casts and rated them for malocclusion severity and perceived treatment difficulty. Multiple regression techniques were used to evaluate the predictive power of the components of malocclusion on the panel's scores. Weightings were calculated from the partial regression coefficients and, when these weightings were applied to the PAR index, the association between the panel's opinion and the PAR index scores was increased.

Analysis of Variance↗

PubMed1995

The effectiveness of Class II, division 1 treatment.

The aim of this retrospective study was to evaluate the effectiveness of orthodontic treatment in terms of two outcome variables, namely, the percentage change in a valid and reliable occlusal index, the Peer Assessment Rating (PAR) score, and the duration of treatment. Data were collected from the records of 250 patients with Class II, Division 1 malocclusions who were treated in the Orthodontic Department of the University of Pittsburgh between 1977 and 1989. The relationships between the outcome and the treatment variables were analyzed with multiple regression techniques. Those variables significantly associated with the duration of treatment (p < 0.01) were (1) the pretreatment PAR score, (2) the number of treatment stages, (3) the percentage of appointments attended, (4) the number of appliance repairs, and (5) whether the patient was treated with or without extractions. The only variable that influenced the percentage change in PAR was the pretreatment PAR score (p < 0.01).

Adolescent↗

PubMed1995

Nasorespiratory characteristics and craniofacial morphology.

The relationship between respiration and craniofacial morphology has been debated for many years. Despite numerous studies, the term 'mouth breathing' remains ill-defined. Still, medical and surgical treatments are performed in order to modify respiration and 'improve' facial growth. This clinical belief continues, in the absence of conclusive evidence, that a causal relationship exists between oral respiration and facial growth, or that such treatment modalities and their associated risks actually modify respiratory mode. Moreover, diagnostic indicators have been postulated for the identification of patients for whom such therapy would be beneficial. The purpose of this study was to investigate the strength of association between mode of respiration and craniofacial morphology. In addition, the precision level was calculated for two popular cephalometric tests for possible nasal impairment. The results suggest that: (1) cephalometric analyses are poor indicators of nasal impairment and should not be used in clinical decision making, and (2) facial morphology and respiratory mode are unrelated.

Adenoidectomy↗

PubMed1994

Developing measures of patients' perceptions of orthognathic surgery.

Measurements of patients' perceptions of the benefits, costs, and risks of orthognathic treatment are needed to assess the utility of alternative treatments, and to assess and improve patient education to make informed decisions. A two-part study was conducted to develop and evaluate measures assessing patients' perceptions of the benefits and risks of orthognathic surgery in comparison to an orthodontics-only approach or no treatment. The first part of this study included 49 patients who had completed orthodontics and orthognathic surgery and 34 patients considering orthognathic surgery. All patients were asked to complete an open-ended telephone questionnaire about their perceptions of the benefits and risks of orthognathic surgery and of alternative options. Patients' answers were sorted into categories, and the second part of this study included a closed-form written questionnaire to assess the perceived likelihood of possible outcomes in each category. Reliability of the questionnaire was assessed using Cronbach's alpha coefficient of internal consistency reliability. Cronbach's alpha ranged from 0.74 to 0.91 when the instrument was used to assess either overall benefits or risks of orthognathic surgery, orthodontics only, or no treatment, indicating acceptable reliability for each of these uses. Subscales concerning more narrowly defined aspects of benefits and risks were less reliable than the overall scales.

Adult↗

PubMed1993

The influence of growth hormone (rhGH) therapy on tooth formation in idiopathic short statured children.

The purpose of this preliminary study was to evaluate tooth formation in children with idiopathic short stature, before and during treatment with recombinant growth hormone (rhGH). Twenty-nine short-statured children ages 6 to 13 years were assigned into two treatment groups, an "experimental" group (n = 18), which received rhGH, and a "control" group (n = 11), which was observed for 1 year before commencing rhGH treatment. Clinical and radiographic records were obtained at the initial, year 1, and year 2 visits. Tooth formation and stature were assessed by calculating Z-scores, appropriate for the age and gender of each child. Delta-Z scores, which measure the change in Z-score over time, were also calculated between annual visits. Height was measured and recorded every 3 months, and Z-score statural norms for age and gender were derived from the 1977 National Center for Health Services national probability sampling. Tooth formation standards were derived from Moorrees et al. A matched control sample for tooth development was derived from untreated children. Tooth formation was initially delayed although the degree of reduction in stature exceeded the initial degree of delay in tooth formation. During this 2-year study, rhGH therapy had a significant influence on acceleration or gain in stature, but did not have a significant influence on tooth formation.

Adolescent↗

PubMed1993

Associations between severity of dentofacial deformity and motivation for orthodontic-orthognathic surgery treatment.

The successful outcome of orthognathic surgery is related to patient satisfaction and motivation. The aim of this retrospective study was to analyze the association between 1) severity of dentofacial deformity derived from cephalometric measures and 2) patient motivation for treatment. The initial cephalograms of 142 patients aged 16 years or older from the Dentofacial Program of the University of Michigan were traced and digitized. Inclusion criteria were established by assigning ANB 4 degrees to 15 degrees to define severe skeletal Class II (n = 65) and ANB - 15 degrees to -4 degrees to define severe skeletal Class III (n = 20). Motivation for orthodontics and surgery was derived from clinician administered forms scaled 1-10 with Low (1-5) and High (8-10). The cephalometric measure ANB was significant (p = 0.02) for high/low motivation for orthodontic treatment using Student's t test. No other cephalometric measures were significant for high/low motivation for orthodontics or surgery using Student's t test. Class II patients were significantly (p = 0.014) more motivated than Class III patients for orthodontic treatment. No significant difference was found for motivation for surgery between skeletal Class II and skeletal Class III patients. Patients with severe sagittal Class II deformities had higher motivation for orthodontics than surgery. The cephalometric measure, ANB, defining severe skeletal Class II and Class III patients did predict motivation level for orthodontics. None of the other 18 cephalometric measures were predictive of patient motivation for either orthodontics or surgery.

Adolescent↗