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Biomedical subjects

P S Vig

Publications and source records attributed to P S Vig.

At least 19 recordsLinked to original sources
PubMed1991

Attitude variables of dentofacial deformity patients: demographic characteristics and associations.

For patients to obtain satisfaction from surgical orthodontic treatment, a concordance needs to exist between the patients' concerns and expectations and the clinician's outcome measures of success. In this study, 231 patients 16 years or older were analyzed to define attributes of treatment that relate to patient satisfaction with outcome. The most prevalent patient concerns were related to facial and dental esthetics, and the effect of the dentofacial deformity on the quality of life was associated with a significantly higher motivation for surgical treatment.

Adolescent↗
PubMed1991

Sensitivity and specificity of diagnostic tests for impaired nasal respiration.

Diagnostic tests are imperfect and vary in their sensitivity and specificity. The degree of imprecision may be calculated to yield probability estimates of accuracy for both the positive and negative predictions of tests under various conditions. Such information enables clinicians to decide whether to accept or reject test results or the tests themselves. Two pilot studies are reported to establish the diagnostic potential of cephalometric measurements and nasal resistance values for the identification of upper airway impairment. A linear estimate of adenoid size and an area index of adenoid encroachment in the nasopharynx were evaluated as diagnostic tests for increased nasal resistance. The sensitivity of the tests was 31.8% and 18.2%, while specificity was calculated at 83.3% and 66.6%, respectively. In the second study, nasal resistance was evaluated as a test to identify persons whose respiratory mode was equal to or less than 75% nasal airflow. At a NRz value of 5.0 cm H2O per liter per second, the sensitivity of this test was 41.2% and the specificity was 84.0%; with the critical value of NRz at 3.5 H2O per liter per second, the sensitivity was 64.7% and the specificity was reduced to 60.0%. The results suggest that these tests are too imprecise for the reliable identification of either those who might benefit from treatment or those for whom treatment is unlikely to yield benefits.

Adenoids↗
PubMed1991

Consistency of orthodontic treatment decisions relative to diagnostic records.

The purpose of this study was to evaluate how incremental information obtained from different types of diagnostic records contributes to the determination of orthodontic treatment decisions. Pretreatment records of 57 orthodontic patients were assessed by five orthodontists who were part-time faculty members and also in private practice. This sample consisted of dental school orthodontic patients who had Class II malocclusions and included patients at three different dental developmental stages. The following diagnostic records were used: study models (S), facial photographs (F), a panoramic radiograph (P), a lateral cephalogram (C), and its tracing (T). Five combinations of diagnostic records were presented to the orthodontists in the following sequence: (1) S; (2) S + F; (3) S + F + P; (4) S + F + P + C; and (5) S + F + P + C + T. The simultaneous interpretation of all diagnostic records (S + F + P + C + T) was used as the "diagnostic standard." There was a diagnostic standard for each of the patients and for each of the orthodontists. The diagnostic standard was achieved: (1) S = 54.9%, (2) S + F = 54.2%, (3) S + F + P = 60.9%, and (4) S + F + P + C = 59.9%. Thus, in a majority of cases (55%), study models alone provided adequate information for treatment planning, and incremental addition of information from other types of diagnostic records made small differences.

Adult↗
PubMed1991

The effects of maxillary surgery on nasal respiration.

Le Fort I osteotomies frequently involve impaction of the maxilla into the nasal cavity, potentially affecting nasal form. It has been speculated that a concomitant change in nasal function may occur. The purpose of this study was to determine if there is an association between maxillary position and nasal function and to evaluate the influence of Le Fort I surgery on nasal function. Presurgical and postsurgical nasal resistance and percent nasal respiration were compared in 36 patients. Results indicated a mean change in nasal resistance 1 year after surgery, but mean percent nasal respiration did not change significantly. No prediction could be made for any patient relative to the effect of maxillary surgery on the nasal function parameters. No consistent association could be found between the amount or direction of maxillary surgical movement or the position of the maxilla and nasal respiration.

Adolescent↗
PubMed1990

External nasal morphology and respiratory function.

Clinicians have been known to characterize nasal respiratory function on the basis of subjective appraisal of external facial morphology. Certain nasal morphologic features have been assumed to be associated with impaired nasal function. The purpose of this study was to develop measures of anterior external nasal morphology and to determine whether any of these measures correlate with nasal function. Nasal casts were produced from impressions of 60 postpubertal white subjects from which four measures were made to characterize nasal morphology: (1) nasal base shape, (2) minimum nasal orifice width, (3) nasal orifice shape, and (4) nasal orifice area. Nasal function was evaluated by measuring nasal airway resistance by means of posterior rhinomanometry and by measuring the air respired nasally and orally by means of the simultaneous nasal and oral respirometric technique. No significant correlations were found between external nasal morphology and nasorespiratory function. These findings underscore the necessity of avoiding assumptions about breathing function on the basis of clinical appraisal of external nasal form.

Adolescent↗
PubMed1990

The duration of orthodontic treatment with and without extractions: a pilot study of five selected practices.

Contemporary orthodontic practice is diverse, both in the variety of clinical problems treated and in the methods used. Practices differ with respect to their patient composition as well as in many variables relative to treatment protocols. Such heterogeneity makes it difficult to make valid generalizations concerning the characteristics of orthodontic treatment procedures or outcomes; yet data and methods are required for assessment of issues of efficacy and utility. The frequency of orthodontic extractions is an objective criterion that distinguishes practices and may also be related to differences in treatment outcome variables, such as duration. Following a telephone survey to estimate extraction rates in the practices of 238 Michigan orthodontists, five practices with very high or low reported rates were chosen for this pilot study. Our primary aim was to determine whether a systematic relationship existed between the relative frequency of extraction treatments and the duration of active appliance therapy. Records of 438 patients from these practices were examined. The extraction rates of the practices ranged from a low of 25% to a high of 84%. Treatment duration was affected by several variables, such as the number of arches treated, the number of treatment phases, and the practice selected. When the data for all five practices were pooled, and all of the extraction versus nonextraction treatments were compared, the mean durations of treatment were 31.2 and 31.3 months, respectively. Data from individual practices, however, indicated that extraction treatment in each of the practices was of longer duration than nonextraction therapy. These differences in duration were 3.0, 6.6, 2.4, 3.0, and 7.3 months in the five practices.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

The prevalence of orthodontic extractions.

The controversy regarding extractions for orthodontic treatment continues and today is invoked by some as a feature of the "standard of care." For this and other reasons, it is necessary to have contemporary data on the general prevalence of orthodontic extractions and the interpractice range of extraction rates in current specialty practice and, if possible, also to establish possible reasons for, and consequences of, the extraction versus nonextraction decision. Although all treatment decisions are made on a case-by-case basis, practitioners appear to have personal preferences for or against extractions and hence adopt policies with different degrees of aversion to or bias toward extraction therapy. A number of factors enter into the extraction decision. These include features of the malocclusion, objectives of treatment, and the technique selected to accomplish desired results. The present study does not address such issues but merely serves to provide epidemiologic data to estimate extraction frequency in contemporary orthodontic practice. Accordingly, a telephone survey of all licensed orthodontists in Michigan was conducted to determine their subjective estimates of extraction rates for patients in their practices. There were 238 respondents, for a response rate of 90.2%. Reported rates range from 5% to 87%. We then selected five practices from the extremes of the reported extraction rates. Three practices from the high end and two from the low end were included for an examination of patient records. Records of a total of 438 patient whose treatment had been completed were reviewed. The actual extraction rates for these practices ranged from 25% to 85%, which differed considerably from the clinicians' subjective estimates.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1989

Lower anterior face height and lip incompetence do not predict nasal airway obstruction.

The controversy regarding nasal obstruction and malocclusion has been largely due to the inability to quantitate nasal airway function and hence objectively determine the mode of breathing. The purpose of this study was to measure the nasal airway resistance of patients before and after rapid maxillary expansion (RME), to compare them to a control group of subjects not receiving RME, and to measure oral/nasal airflow ratios (respiratory mode). An evaluation of the statistical associations between anterior facial height, lip posture, oral/nasal airflow ratios, and nasal resistance was undertaken. The effects of RME on nasal resistance have been reported elsewhere. We found that variation, for resistance values, was very high, and thus the median response for the group was not an adequate estimation of individual response. In this paper we describe associations between lip posture, lower anterior facial height, and nasal resistance. No significant correlations could be established between respiratory and morphologic features. Lower anterior facial height was greater in the lips apart posture group. However, there was no significant correlation between percent nasality and lower anterior facial height. A small negative correlation (r = -0.47) existed between nasal resistance and percent nasality, but this relationship was not linear. Thus, it was not possible to predict percent nasality from nasal resistance data. Furthermore, no correlation was found between the amount of expansion and changes in nasal resistance. This paper was originally submitted June 1986, and revised October 1988.

Adolescent↗
PubMed1988

Respiration characteristics in subjects diagnosed as having nasal obstruction.

The purpose of this study was to determine the respective oral and nasal contributions to total respiration in patients scheduled for surgical corrections of nasal obstruction. The effect of anterior nares expansion and/or nasal decongestant administration on the nasal component of breathing was also examined in these patients. Although variability among subjects was demonstrated in the ratio of nasal respiration to total respiration, 25% of the "nasally-obstructed" patients were 100% nasal breathers and no patient had a nasal component less than 18% of total respiration. Great variability existed among the patients in their response to nares expansion and/or decongestant administration. Collectively, they demonstrated no significant mean increase in nasal respiration with nares expansion alone. The patients demonstrated an increase with administration of the decongestant and with decongestant combined with nares expansion. The latter condition resulted in an increase that was greater than with decongestant alone. The implication of this study is that the traditional diagnostic terms "mouth breathing" or "nasal obstruction" are not useful. They do not describe the type, location, or severity of an obstruction or the relative contribution of the nose and mouth to respiration. Many patients who experience symptoms or have signs of nasal obstruction can functionally compensate to maintain 100% nasal breathing.

Adult↗
PubMed1987

The effect of rapid maxillary expansion on nasal airway resistance.

The purpose of this study was to evaluate changes in nasal resistance to airflow in persons undergoing rapid maxillary expansion and to reevaluate the responses at a 1-year follow-up. Nasal resistance measurements, assessed in four modes (natural state, anterior nares dilation with Tygon tubing, following administration of decongestant, and nares dilation with tubing and decongestant), were taken on a group of 38 patients receiving rapid maxillary expansion and compared with a control group not receiving expansion. Thirty-three of the patients were reevaluated 9 to 12 months after expansion was completed. Eighteen subjects in the control group were also reevaluated. Oral/nasal airflow rates (percent nasality) were recorded for the control group and for some of the expansion patients. Results indicated that some subjects receiving rapid maxillary expansion had a significantly higher nasal resistance than the control group. There was a significant median reduction in nasal resistance following rapid maxillary expansion, measured in the natural state only, and this appeared to be stable up to 1 year after maximum expansion was obtained. Rapid maxillary expansion appeared to effect an expansion at the anterior nares, which contributes to nasal resistance reduction. Individual variation in nasal resistance values was considerable and hence the median response for the group was not a reliable estimate of individual response. Due to the high individual response variability, rapid maxillary expansion is not a predictable means of decreasing nasal resistance.

Adolescent↗
PubMed1987

The effect of methodology on the determination of nasal resistance.

Confusion and controversy continue to characterize scientific understanding of the role that respiration plays in modifying growth. Identification of specific methods to provide valid measurement of nasorespiratory function can help clinicians to (1) make an informed judgment regarding postulated relationships between respiration and growth, (2) test the validity of a diagnosis of impaired nasal respiration or "mouth breathing," and (3) evaluate the efficacy of treatment for nasal obstruction. A method that has been frequently used to quantify nasorespiratory function is nasal resistance measurement or rhinomanometry. This investigation used a common form of this method, studying 25 adult subjects to examine the effect of a number of variables in methodology on nasal airway resistance values. Results indicate that resistance to nasally inspired air was not significantly different from resistance to nasally expired air. However, a significant difference in estimating resistance was found between airflow rates of 0.25 and 0.5 L/sec, with nasal resistance increasing at the higher flow rate. Determination of the method error indicated that the technique was reliable and accurate for the sample studied. It was found that both expansion of the anterior nares and use of a nasal decongestant spray produced a decrease in mean nasal resistance. The study emphasizes the need to standardize the method of determining nasal resistance in order to permit comparisons among studies, to obtain a more reliable estimate of resistance, and to identify the location of maximum constriction in the nasal airway.

Adult↗
PubMed1987

An improved technique for the simultaneous measurement of nasal and oral respiration.

A technique is described to record and measure both the nasal and oral components of respiratory airflow. The method is a modification of a previously reported technique, and represents an improvement in terms of accuracy, speed, convenience, and facility in both the acquisition and analysis of a large set of data per subject. The equipment and associated computer configuration permits a temporal characterization of inspiratory and expiratory parameters of both nasal and oral airflow, nasal airway resistance computation at predetermined flow rates, and the calculation of estimates of the minimum cross-sectional area of the nasal air passage.

Airway Resistance↗
PubMed1979

Orthodontic attitudes toward national health insurance.

Data were obtained by surveying North Carolina orthodontists by means of a mailed questionnaire. Their responses were coded to make possible analysis by computer and were compared to responses from a national sample of dentists in the 1975 Survey of Dentists. Both North Carolina orthodontists and dentists nationwide agreed that some form of dental care should be provided if a national health insurance system were established. Compared to the dentists surveyed nationwide, the orthodontists favored a wider range of coverages but advocated providing a narrower scope of dental services. They indicated more strongly their general belief that a government health program would lead to regulation outside the private sector. The orthodontists disagreed more strongly with the claim that government health programs could provide more people with high-quality dental care. Both groups anticipated that comprehensive dental care in a national health insurance system would result in fixed fees set by the government. Only 62 percent of the orthodontists polled were familiar with HMOs. Of this group, nearly 90 percent chose not to contract with these organizations.

Attitude↗