Browsing by Subject "Mandible"

Now showing 1 - 10 of 12
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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 Clinical Study Evaluating a Mandibular Repositioning Appliance to Treat Obstructive Sleep Apnea
    (1992) Coghlan, J. Kevin; Roberts, W. Eugene; Beiswanger, Bradley B.; Shanks, James C.; Garner, LaForrest D.; Hennon, David K.; Nelson, Charles L.
    The study evaluated the effects of a mandibular repositioning appliance (MRA) in patients with obstructive sleep apnea. The MRA was designed to hold the mandible anteriorly in an attempt to maintain a patent airway. Eleven subjects completed a full-night polysomnogram wherein their normal sleep was recorded half the night without the appliance (control) and the other half with the appliance (test). The sequencing of test and control halves was randomly assigned to avoid bias. After seven subjects were tested with the MRA, the MRA was modified for four additional patients by placing anterior vertical elastics (MRA*) to minimize the opening of the mandible. The skeletal and soft tissue changes with both appliances were analyzed using lateral cephalometric radiographs. The MRA was found to have no significant effect on the obstructive sleep apnea patients as a group. Individual response to the appliance varied from noticeably worse to marked improvement. Subject #2A exhibited the reduction of a moderate-to-severe apnea (Apnea-hypopnea index 55.92) to a clinically acceptable level (Apnea-hypopnea index 9.57) with appliance wear. The treatment was considered successful. Significant cephalometric changes with appliance wear were increased lower facial height, a superiorly positioned hyoid bone relative to the mandibular plane, and a decreased posterior airway space. No cephalometric measurement could accurately predict the outcome of the treatment, and posterior airway space, commonly measured in sleep research, was not reliable. The mandibular repositioning appliance was effective in treating a small percentage of individuals with obstructive sleep apnea. A polysomnogram was needed to quantitatively measure the effectiveness of treatment. Under no circumstance should a subjective evaluation by the patient or the clinician be used to assess treatment results. Further investigation is required to evaluate the long-term effectiveness of this treatment. Periodic follow-up sleep studies are required for any patient treated with this appliance until more long term studies are completed.
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    Diagnostic efficacy of novel cephalometric parameters for the assessment of vertical skeletal dysplasia
    (Tabriz University of Medical Sciences, 2022) Gandhi, Kaveri Kranti; Rai, Anshu; Periodontology, School of Dentistry
    Background. An accurate diagnosis of vertical skeletal abnormalities presents several challenges. Specific cephalometric parameters can be effectively used for this purpose; however, the diagnostic accuracy of these parameters has not been entirely ascertained. This study examines the effectiveness of two novel cephalometric parameters for diagnosing vertical dysplasia. Methods. In this retrospective study, orthodontic patients were distributed into three study groups: average growth (AGG), horizontal growth (HGG), and vertical growth (VGG). The efficacies of the sum of angles (maxillary, mandibular, and ramal) and the height ratio (lower anterior facial height [LAFH]/upper anterior facial height [UAFH]) in identifying different growth patterns were examined. Receiver operating characteristic (ROC) curves were employed to assess the diagnostic precision quantitatively. Results. A total of 150 patients were included and divided equally among the three study groups. The ramal and mandibular angles varied across AGG, HGG, and VGG; however, the maxillary angle and the sum of these three angles did not vary significantly. There was a substantial variance in LAHF, UAHF, and their ratio in the three groups. The height ratio had 88% and 92% sensitivity to diagnose VGG and HGG, with cut-off values of 46 and 34, respectively (P<0.001). Conclusion. Height ratio values varied considerably depending on the facial growth patterns, suggesting its efficacy as a diagnostic tool for skeletal dysplasia, with greater reliability for positive treatment outcomes.
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    IGF-I Receptor Localization and Constant Infusion of a Supraphysiologic Dose of IGF-I in the Sprague-Dawley Rat
    (1993) Alford, Timothy J.; Simmons, Kirt; Roberts, W. Eugene; Garetto, Lawrence P.; Hughes, Christopher; Bixler, David
    Previous studies have shown an increased growth of the tibial growth plate in rats infused with supraphysiologic doses of IGF-I. However, no one has demonstrated this effect on the TMJ in vivo. To determine the effect of a constant infusion of IGF-1 on the TMJ, 20 Sprague-Dawley rats were divided into three groups: (1) control, (2) surgical control, and (3) IGF-1 and placebo infused. IGF-I was delivered at a rate of 1 μg/day over the TMJ via osmotic minipumps. lntravital bone labels were administered at two-week intervals to monitor growth rate. Following sacrifice, seven mandibular (Mn) dimensions were measured anthropometrically. The mandibles were then imbedded in acrylic and stained with tetrachrome to visualize the Mn cartilage. Fluorescence microscopy was utilized to measure the Mn growth between bone labels and calculate growth rates. In addition, the hypertrophic cartilage layer thickness was measured photomicrographically. ANOVA showed no significant difference (P<0.05) in growth rates or cartilage thicknesses between the groups. However, multiple t tests did show an increase in several Mn dimensions (increase in length from gonion to the mental foramen; increase in length from condylion to the mental foramen; and increase in condylar head anterior-posterior length) in the experimental animals comparing the IGF-I infused side with the placebo infused control side. Therefore, it was concluded that IGF-I, when infused at a constant supraphysiologic dose, may increase mandibular growth in certain directions. The present study is not able to definitively demonstrate that these increases are due to direct effects on Mn cartilage growth.
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    Myofibroma of the body of mandible: A case report of a solitary lesion
    (Wolters Kluwer, 2023) Khaleghi, Abrahim; Dehnashi, Nikki; Matthews, N. S.; Oral and Maxillofacial Surgery and Hospital Dentistry, School of Dentistry
    Myofibromas are rare benign lesions and are often found as solitary entities. The treatment of the lesion is complete excision and the recurrence is rare. A 56-year-old female presented to the Oral and Maxillofacial Surgery clinic for further evaluation and management of a solitary lesion of the right body of the mandible that was first noticed incidentally by her referring dentist. An incisional biopsy was first performed in the clinic with the diagnosis of myofibroma. The patient was then treated with complete excision of the lesion and extraction of the adjacent teeth. The final biopsy report confirmed the initial diagnosis of myofibroma. Intraosseous solitary lesion of the mandible is a rare lesion with a handful of reported cases. Uniquely, the diagnosis of myofibroma in this 56-year-old is the oldest reported case of myofibroma. There are distinct histopathological features of the lesion that distinguishes this entity from other closely resembling lesions.
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    Occlusal Displacement of Teeth Due to Flexure of the Mandible
    (1995) Eichel, David A.; Katona, Thomas R.; Analoui, Mostafa; Arbuckle, Gordon R.; Chen, Jie; Shanks, James C.
    It has been proposed that jaw deformation during function may be a contributor to supraosseous tooth eruption. This could be through a transient pressure gradient in the flexed bone and/or tension in the PDL fibers produced by socket deformation. Thus, the purpose of this study was to determine if forces applied to a fresh frozen canine mandible can lead to occlusal displacement of a tooth. Seven hemisected canine mandibles (14 specimens) were used to test this hypothesis. A force cycle (10 N to 100 N to 300 N) was applied by a Bionix testing machine (MTS TM Systems Corp., Minneapolis, Minn.) to the mandible in three point bending. Digital radiographs were taken at each change in force level using computer digitized radiography (CDR, TM Schick Technologies, Inc., Long Island City, N.Y.). By measuring the relative movement of metal markers (1 mm steel balls) placed into the mandible and the crown of the 2nd premolar, the amount of tooth eruption was calculated. With cyanoacrylate cement (Archer® Instant Bonding Adhesive, Tandy Corp, Ft. Worth, Texas) injected into the PDL space of the same tooth, the test was repeated one week later. These "ankylosed" teeth served as controls. The eruption distances were compared between the experimental and the ankylosed teeth by means of repeated measures analysis of variance. The only significant occlusal displacement was noted as the force was initially raised to 100 N (21.7 ± 40.6 μm). Due to the possible breakdown of the cyanoacrylate cement, the ankylosed teeth also showed evidence of eruption with the continued application of force. Although significant eruption was noted, the displacements were very small. PDL degradation, viscoelastic behavior, measurement of small displacements, limited resolution radiography, and two dimensional analysis are contributing factors to the uncertainty of the results. Further investigation is required to determine if jaw deformation during function is a viable mechanism leading to the occlusal displacement of teeth.
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    Prediction of the Post-Pubertal Mandibular Length and Y Axis of Growth by Using Various Machine Learning Techniques: A Retrospective Longitudinal Study
    (MDPI, 2023-04-26) Wood, Tyler; Anigbo, Justina O.; Eckert, George; Stewart, Kelton T.; Dundar, Mehmet Murat; Turkkahraman, Hakan; Orthodontics and Oral Facial Genetics, School of Dentistry
    The aim was to predict the post-pubertal mandibular length and Y axis of growth in males by using various machine learning (ML) techniques. Cephalometric data obtained from 163 males with Class I Angle malocclusion, were used to train various ML algorithms. Analysis of variances (ANOVA) was used to compare the differences between predicted and actual measurements among methods and between time points. All the algorithms revealed an accuracy range from 95.80% to 97.64% while predicting post-pubertal mandibular length. When predicting the Y axis of growth, accuracies ranged from 96.60% to 98.34%. There was no significant interaction between methods and time points used for predicting the mandibular length (p = 0.235) and Y axis of growth (p = 0.549). All tested ML algorithms accurately predicted the post-pubertal mandibular length and Y axis of growth. The best predictors for the mandibular length were mandibular and maxillary lengths, and lower face height, while they were Y axis of growth, lower face height, and mandibular plane angle for the post-pubertal Y axis of growth. No significant difference was found among the accuracies of the techniques, except the least squares method had a significantly larger error than all others in predicting the Y axis of growth.
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    A Qualitative Engineering Analysis of Occlusion Effects on Mandibular Fracture Repair Mechanics
    (SAGE-Hindawi, 2011-08) Katona, Thomas R.
    Objectives. The purpose of this analytical study was to examine and critique the engineering foundations of commonly accepted biomechanical principles of mandible fracture repair. Materials and Methods. Basic principles of static equilibrium were applied to intact and plated mandibles, but instead of the traditional lever forces, the mandibles were subjected to more realistic occlusal forces. Results. These loading conditions produced stress distributions within the intact mandible that were very different and more complex than the customary lever-based gradient. The analyses also demonstrated the entirely different mechanical environments within intact and plated mandibles. Conclusions. Because the loading and geometry of the lever-idealized mandible is incomplete, the associated widely accepted bone stress distribution (tension on top and compression on the bottom) should not be assumed. Furthermore, the stress gradients within the bone of an intact mandible should not be extrapolated to the mechanical environment within the plated regions of a fractured mandible.