Browsing by Subject "Malocclusion"

Now showing 1 - 10 of 13
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    An Investigation of Dental Arch Form in a Sample of Malocclusions
    (1975) Page, Robert M.; Garner, LaForrest D.; Shanks, James C., Jr.; Dirlam, James H.; Potter, Rosario H.; Barton, Paul
    The objective of this study was to investigate the geometric arch forms found in a sample of malocclusions. The specific objectives were to determine if there was a basic geometric arch form which described all of the sample, to identify the typical arch form in each of the classes of malocclusion, and to determine if there was a statistical difference in form among the various classes in each arch. A sample of 99 maxillary and mandibular plaster casts were collected from the Department of Orthodontics, Indiana University School of Dentistry, and classified according to Angle's classification of malocclusion. Occlusograms were taken of all casts. The center of incisal edges, cusp tips of cuspids and bicuspids, and bifurcation of molars were marked and traced on acetate tracing paper from the occlusogram). A straight line was drawn between these points giving the final dental arch form. A coordinate· system was established on each arch form which allowed the classification of the arch form by Hayashi's method 60. The results showed that no basic arch form described the sample. The average arch form for each classification of malocclusion varied between classes and between arches. Statistically, maxillary arch form of the Class II division 2 differed significantly from maxillary Class I, Class II division 1, and Class III malocclusions. Class II division 2 mandibular arch form differed significantly only from the mandibular Class I malocclusion.
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    An Investigation of the Effects of Incisal Overjet on Mandibular Movement During Speech
    (1979) Lipken, Neil A.
    The objective of this study was to explore the possible existence of mandibular protrusion during speech for those subjects possessing at least three millimeters of incisal overjet. The most important clinical consequence would be the question of whether or not temporomandibular joint symptomatology becomes manifest with advancing age in these subjects. If proof of a “speech protrusion” were to be found in the course of this research, a future investigation would be in order using an older group of subjects with incisal overjet to answer the above question. A Class I control group was gathered, consisting of ten female subjects, all of whom had zero incisal overjet. Ten female subjects also made up a Class II group, with the criterion being a minimum of three millimeters of incisal overjet. The age range of all the subjects, with one exception, was 17 to 30, none of the subjects had any perceptible speech defects. In both groups, a wide range of overbite was sought and obtained. Models as well as lateral headplates were taken for all twenty subjects. The test instrument was the Mandibular Kinesiograph located in the Complete Denture Department of the Indiana University School of Dentistry. The test parameter components included “s,” a consonant, and the three vowels representing the extremes of the vowel diagram, “ee,” “oo,” and “ah.” These were combined to yield three consonant-vowel combinations, namely “ee-see,” “oo-soo,” and “ah-sah.” After making a reference scribe which consisted of habitual occlusion, a protrusive slide to the end-to-end incisal position, and a retrusive slide, if present, back to centric occlusion, a given subject was asked to repeat each of the consonant-vowel combinations five times. Thus for each subject there were three tracings, each with five trials and a reference scribe. The data were collected by a tape recorder attached to the Kinesiograph, and the subsequent tape sent to Pharmadynamics Research, Inc. in West Lafayette, Indiana, for computer analysis. The computer’s first step was to take each set of five trials for a given consonant-vowel combination and produce one averaged curve. As a result, each subject was left with three curves. Using the end-to-end incisal position, habitual occlusion, and when present, centric occlusion, as reference points, for all subjects anteroposterior distance measurements were made for “s,” and both anteroposterior and vertical distance measurements were made for “ee,” “oo,” and “ah.” These distances were then compared using F-tests and t-tests both between and among the classes (Class I and Class II groups). Statistically significant differences, or lack of, were searched for in evaluating the t-test results. Although the basic purpose of the research was to seek proof of a Class II mandibular protrusion, during “s” to a typical Class I anteroposterior “s” posture, other secondary findings centered around the anteroposterior and vertical positions of “ee,” “oo,” and “ah” relative to habitual occlusion and centric occlusion. The results of the research were as follows: (1) Class II subjects demonstrated complete anterior translation of the mandible during “s” production, validifying the main hypothesis of the study. There was no statistical significance between Class I and Class II “s” position. (2) For the Class I group only, the “oo-soo” “s” mandibular position was statistically posterior to the “ee-see” “s,” with the “ah-sah” “s” appearing to be in an intermediate anteroposterior position. (3) The Class II “ah” mandibular position was more inferior than that of the class I “ah.” (4) For both class I and Class II, the order of mandibular position from superior to inferior was “oo,” “ee,” and then “ah.” (5) The class I “ee” mandibular position was posterior to that of the Class II “ee.” (6) For both Class I and Class II, then mandibular position of “ah” was posterior to that of both “ee” and “oo.”
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    A Comparison of Maxillary Arch Form and Dento-Skeletal Patterns in Japanese and Caucasian American Individuals Exhibiting Class II Div. 1 Malocclusions
    (1960) Bell, S. Wallace
    A study was made comparing Japanese and Caucasian American Class II, Div. 1 malocclusions with respect to maxillary arch form and dento-skeletal patterns. For the arch form study, the maxillary casts of twenty Caucasian and eighteen Japanese individuals of comparable ages were evaluated. Dental arch indices were calculated for each individual and the mean values of the two groups were tested for significant difference. The Caucasian arches exhibited a more narrow tapering form than did the Japanese. In the second part of the study, eighteen Japanese and eighteen Caucasian American Class II, Div. 1 malocclusions were evaluated for differences in dento-facial architecture. Downs' radiographic cephalometric analytical procedure was used. Mental prominence was also measured using a technic which was described. It was found that the facial plan angle and mandibular plane angle in the Japanese group was more obtuse. The mental prominence in the Caucasian group was larger than in the Japanese group.
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    A Longitudinal Cephalometric Study of Several Factors Involved in Overbite Correction and Recurrence in Class II (Angle) Malocclusions
    (1960-12) Carr, W. Kelley
    This study is a cephalometric investigation of twenty-two patients (nineteen females and three males) in which problems of overbite evaluation, correction and recurrence were investigated. Problems of anterior cranial base superpositioning and the measuring of ramus growth are discussed. Two methods of measuring overbite are discussed and evaluated. Where overjet exists, the overjet and the axial inclination of the central incisors were found to affect the potential overbite problem. The range of depression of both maxillary and mandibular central incisors in this sample is discussed. The suggestion is made that this range indicates important information to us for indicating limitations and opportunities in treatment planning and appliance design. An increase in overbite following active treatment was observed in all members of the sample. This was also true when intermaxillary height was increasing following active treatment. A strong tendency for maxillary and mandibular central incisors to elevate following the completion of the active treatment was noted. The individual data suggests that the elevation of teeth following active treatment may be dependent upon other factors than the amount the tooth was depressed during active treatment.
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    Orthognathic speech pathology: impacts of Class III malocclusion on speech
    (Oxford University Press, 2022) Lathrop-Marshall, Hillary; Keyser, Mary Morgan B.; Jhingree, Samantha; Giduz, Natalie; Bocklage, Clare; Couldwell, Sandrine; Edwards, Haley; Glesener, Tim; Moss, Kevin; Frazier-Bowers, Sylvia; Phillips, Ceib; Turvey, Timothy; Blakey, George; White, Ray; Mielke, Jeff; Zajac, David; Jacox, Laura A.; Biostatistics and Health Data Science, Richard M. Fairbanks School of Public Health
    Introduction: Patients with dentofacial disharmonies (DFDs) seek orthodontic care and orthognathic surgery to address issues with mastication, esthetics, and speech. Speech distortions are seen 18 times more frequently in Class III DFD patients than the general population, with unclear causality. We hypothesize there are significant differences in spectral properties of stop (/t/ or /k/), fricative (/s/ or /ʃ/), and affricate (/tʃ/) consonants and that severity of Class III disharmony correlates with the degree of speech abnormality. Methods: To understand how jaw disharmonies influence speech, orthodontic records and audio recordings were collected from Class III surgical candidates and reference subjects (n = 102 Class III, 62 controls). A speech pathologist evaluated subjects and recordings were quantitatively analysed by Spectral Moment Analysis for frequency distortions. Results: A majority of Class III subjects exhibit speech distortions. A significant increase in the centroid frequency (M1) and spectral spread (M2) was seen in several consonants of Class III subjects compared to controls. Using regression analysis, correlations between Class III skeletal severity (assessed by cephalometric measures) and spectral distortion were found for /t/ and /k/ phones. Conclusions: Class III DFD patients have a higher prevalence of articulation errors and significant spectral distortions in consonants relative to controls. This is the first demonstration that severity of malocclusion is quantitatively correlated with the degree of speech distortion for consonants, suggesting causation. These findings offer insight into the complex relationship between craniofacial structures and speech distortions.
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    The relationship between the ABO discrepancy index and treatment duration in a graduate orthodontic clinic
    (Allen Press, 2011) Parrish, Laura D.; Roberts, W. Eugene; Maupome, Gerardo; Stewart, Kelton T.; Bandy, Robert W.; Kula, Katherine S.; Orthodontics and Oral Facial Genetics, School of Dentistry
    Objective: To test the hypothesis that there is no relationship between the components of the American Board of Orthodontics (ABO) discrepancy index (DI) and duration of orthodontic treatment. Materials and methods: A retrospective review of 732 patient records with permanent dentition was performed. Pretreatment radiographs and casts were used to determine the DI score. Other data collected were total treatment duration, age, sex, ethnicity, and the date fixed appliances were removed. Reliability tests showed substantial agreement between examiners (Cohen's kappa 0.68-0.94). Pearson and Spearman correlation coefficients were used to assess the association between the DI scores and length of treatment. A multiple variable regression analysis was used to determine which variables predict treatment duration (P < .05 significant). Results: There was a significant association between the DI and treatment duration. There was a significant multivariate association for DI components (occlusions, crowding, overjet, cephalometrics, overbite, lateral open bite, and tooth transposition) and treatment duration. Conclusions: The hypothesis was rejected. This retrospective study of university clinical records showed that the average increase in treatment duration was about 11 days for each point increase in total DI score. Treatment duration was differentially increased by various components of the DI: approximately 6.5 months for tooth transposition; approximately 1 month for crowding, overjet, or overbite; approximately 3 weeks for occlusion discrepancies; approximately 2 weeks for lateral open bite; and approximately 5 days for cephalometric discrepancies.
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    A roentographic cephalometric analysis of the cerebral palsied patient
    (1967) Fetters, Max E. (Max Eugene), 1930-
    This study sought to determine if the dental and oro-facial complex of cerebral palsied patients is different from that of the non-cerebral palsied. Twenty-six cerebral palsied patients between the ages of seven and 18 were examined. A history was taken and a data sheet was completed to record molar and cuspid relationships. The function of. the tongue and lips during swallow was also recorded. Cephalometric and hand and wrist radiographs were taken of each patient. The cephalometric measurements were statistically compared with the normative data of a non-cerebral palsied group. This analysis revealed the cranial flexure angle to be more acute and the gonial angle to be more obtuse. Comparison of the hand and wrist plates with normal standards did not show wide enough differences to conclude that cerebral palsied patients' skeletal age deviates from the chronological age. Although there was a difference in some cephalometric measurements, there is no evidence in this study to show that the incidence of malocclusion and the incidence of factors that contribute to malocclusion are found with greater frequency among cerebral palsied patients.