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A longitudinal morphometric analysis and classification of the Class III individual utilizing the counterpart analysis
Volume 88 Number 1
Reviews and abstracts 85
alignment, gonial angle, and MCF/ramus horizontal dimension. 5. No viable prediction patterns were developed with the counterpart measures used in this study because the facial effects and serial variability that led to the Class II expression demonstrated a broad range of possibilities. A clinician must question the bias in computer-based prediction schemes that do not reflect this variability. 6. To arrive at the most purposeful treatment plan, it is imperative that a diagnosis reflect the biologic complexity of the malocclusion. A Longitudinal Morphometric Analysis Classification of the Class III Individual Utilizing the Counterpart Analysis
and
Charles Ft. Pfister Case
Western
Reserve
University,
Cleveland,
Ohio,
1984
Numerous theories to account for the skeletal pattern involved in the Class III individual have been proposed. Each has examined a possible primary contributor to the prognathic profile. However, there is ample reason to assume that more than one skeletal imbalance in different areas of the craniofacial complex are components of the Class III skeletal pattern. The purpose of this study was to longitudinally evaluate the various anatomic counterparts and their interrelationships within the Class III craniofacial complex and to determine which contributed earliest and to the greatest degree to the prognathic profile. The longitudinal stability of various combinations of these anatomic parts and relationships was also studied. This information will aid in the predictability of a Class III skeletal pattern early in development and allow treatment to be initiated accordingly. By means of Enlow’s counterpart analysis, hypothetical groups were formed on the basis of random combinations of these primary and secondary anatomic parts and relationships. The results of the study are summarized as follows: 1. The Class III 16-year-old sample consisted of 20 subjects of 3 different craniofacial compositions with 3 subtypes of Type II13. All demonstrated a prognathic mandible with a Class III malocclusion. The Class I 16-year-old sample consisted of 20 subjects of 4 different craniofacial compositions with 2 subtypes of Type I3 and 2 subtypes of Type 14. All demonstrated a Class I occlusion. 2. The most stable Class III anatomic parts and relationships were the middle cranial fossa alignment and the mandibular corpus length relative to the maxilla. The most variable Class III anatomic relationships
were the ramus alignment and horizontal width of the ramus relative to the MCF dimension. The Class I subjects were similar to the Class III subjects in variability of the anatomic relationships with a variation of only 10% to 15% in all but two areas. The Class III sample had 25% more backward-positioned MCF than the Class I sample and 90% of the Class III subjects, from 9 years of age, exhibited a mandibular corpus longer than the maxillary corpus, as compared to only 70% of the Class I subjects. 3. The Class III sample exhibited a steady decrease in the number of different craniofacial compositions from 6 to 16+ years of age. In contrast, the Class I sample maintained a high level of different craniofacial compositions throughout the same time period. However, both groups did express a pubertal growth spurt, reflected in the significant increase in variability among the anatomical relationships between the age levels of 9 and 14 years. 4. In the Class III group, the combination of anatomic relationships (including the middle cranial fossa alignment, mandibular corpus length relative to maxilla, ramus horizontal width relative to MCF, and the gonial angle) exhibited a pattern stability of 78% at the g-year level and a 90% stability at the 1Cyear level. The Class I anatomic combinations were too variable to predict higher than 50%. These levels of prediction confidence are for this sample. Further research is needed to determine confidence levels in other samples. Information from Whitney (1983) on a sample of 20 skeletal Class II subjects analyzed in a similar manner was compared to the Class III and Class I data from this study. Following is a summary of the results of this comparison. 1. The Class II 16-year-old sample consisted of 6 different craniofacial compositions with 4 different subtypes, demonstrating a Class II malocclusion. 2. The middle cranial fossa alignment and mandibular corpus length relative to the maxilla was very stable in the Class III sample and extremely variable in the Class II pattern. 3. The Class II sample exhibited a steady increase in the number of different craniofacial compositions, even after 14 years of age. This is contrary to the Class III sample which showed a steady decrease in the number of compositions, especially after the 16year level. The Class I sample did not fluctuate. It maintained instead a significant number of different craniofacial compositions. The overall results from this study and the Class II comparison are summarized as follows: 1. The Class III craniofacial complex exhibited a large amount of change early in development and main-
86
Reviews
and
Sm. J. Onhod. Irrlv 1985
abstracts
tained it partly through puberty. The craniofacial pattern then appeared to undergo only refinements, not total architectural turnover. 2. The Class II craniofacial complex showed less change early in development, but significant increases in the number of changes from a period beginning before puberty and continuing to late adolescence. Many portions of the Class II craniofacial pattern appeared to change at all age levels, as reflected by the large number of individual counterpart changes for each age level. 3. The Class I sample showed Class II tendencies in some anatomic parts and relationships and Class III tendencies in others. It appears from this study that Class I subjects do not constitute a separate dental classification but, rather, a craniofacial composition that has balanced or compensated for the various maxillary and mandibular protrusive tendencies within their present craniofacial complexes. Changes in Synovial Fluid Pressure Altered Mandibular Positions Dennis M. Ward Case Western
Reserve
University,
Cleveland,
Ohio,
due to
1984
The role of the synovial organ in relation to joints other than the temporomandibular has long been investigated. Its responsibilities include nutrition and lubrication to the articular surfaces. The pressure of the synovial fluid has been measured in both long-bone joints and, recently, TMJ’s. Both have demonstrated negative pressure relative to the atmosphere. It is conceivable that changes in mandibular position could have marked effects on the relative pressure of the synovial fluid. This study was designed to measure the synovial fluid pressure in the growing animal, uninhibited by mechanical intervention and by change of the mandibular position. Various functional parameters were investigated including mastication, lateral movements, and opening and closing of the mandible. The resting synovial fluid pressure was found to be subatmospheric in the unaltered TMJ. By functionally positioning the mandible forward, there was a marked rise in pressure with a gradual stabilization and return to the baseline level. With a retruding appliance in place, the synovial fluid pressure increased substantially and failed to return to a subatmospheric level for the duration of the experiment. The fluctuation in synovial fluid pressure could have biologic implications with respect to its role in nutrition and lubrication. Elevated pressures could cause local ischemic changes and decreased lubrication with increased friction to the articular surfaces.
Synovial fluid may be the medium by which pressure changes caused by altered mandibular position are translated to joint surfaces. The findings are summarized as follows: 1. The resting synovial fluid pressure was negative relative to the atmosphere in all 6 joints. The mean value was -3.9 mm Hg. 2. Pressure increased during operator-manipulated jaw positions. When the jaw was released, the pressure returned to the baseline. 3. There was a marked increase in pressure when a protruding appliance was in place. This pressure gradually returned to the baseline. The return was attributed to joint compliance and absorption of fluid. 4. There was a substantial rise in pressure when a retruding appliance was in place. The pressure did not return to the baseline. 5. Mastication produced a marked pressure change. The pressure changes appeared cyclic. 6. Possible relations between fluid pressure/pathosis and growth development were discussed. The hbasurement of Changes in Oxygen Concentration, Redox Potential, pcI, and Temperature in the Periodontal Membrane During Force Application Ira Harold Weiss Case Western
Reserve
University,
Cleveland,
Ohio,
1984
This study dealt with the biologic responses of the tooth-supporting apparatus to an application of force of sudden onset and short duration. The four parameters selected were believed to be especially sensitive to significant changes in tissue respiration and energy-dependent biochemical reactions. The parameters selected for evaluation during force application were oxygen tension, redox potential, pH, and temperature. All of these factors are extremely important in a consideration of any biochemical reaction or chain of reactions that requires energy or liberates energy. Electrodes and companion measurement systems were designed, tested, and applied to an in vivo model. Two animal systems were used. One consisted of the anterior maxillary dental incisors of male hamsters. The periodontal membrane in these teeth was reasonably wide and the bone sufficiently elastic to allow the insertion of extremely thin redox-sensing electrodes. The second animal model was the mandibular premolar teeth in a female dog. This model permitted the application of calibrated forces and allowed access to the periodontal membrane via two approaches: (1) an apicoectomy in the area of the distal root of the man-
Reviews and abstracts 85
alignment, gonial angle, and MCF/ramus horizontal dimension. 5. No viable prediction patterns were developed with the counterpart measures used in this study because the facial effects and serial variability that led to the Class II expression demonstrated a broad range of possibilities. A clinician must question the bias in computer-based prediction schemes that do not reflect this variability. 6. To arrive at the most purposeful treatment plan, it is imperative that a diagnosis reflect the biologic complexity of the malocclusion. A Longitudinal Morphometric Analysis Classification of the Class III Individual Utilizing the Counterpart Analysis
and
Charles Ft. Pfister Case
Western
Reserve
University,
Cleveland,
Ohio,
1984
Numerous theories to account for the skeletal pattern involved in the Class III individual have been proposed. Each has examined a possible primary contributor to the prognathic profile. However, there is ample reason to assume that more than one skeletal imbalance in different areas of the craniofacial complex are components of the Class III skeletal pattern. The purpose of this study was to longitudinally evaluate the various anatomic counterparts and their interrelationships within the Class III craniofacial complex and to determine which contributed earliest and to the greatest degree to the prognathic profile. The longitudinal stability of various combinations of these anatomic parts and relationships was also studied. This information will aid in the predictability of a Class III skeletal pattern early in development and allow treatment to be initiated accordingly. By means of Enlow’s counterpart analysis, hypothetical groups were formed on the basis of random combinations of these primary and secondary anatomic parts and relationships. The results of the study are summarized as follows: 1. The Class III 16-year-old sample consisted of 20 subjects of 3 different craniofacial compositions with 3 subtypes of Type II13. All demonstrated a prognathic mandible with a Class III malocclusion. The Class I 16-year-old sample consisted of 20 subjects of 4 different craniofacial compositions with 2 subtypes of Type I3 and 2 subtypes of Type 14. All demonstrated a Class I occlusion. 2. The most stable Class III anatomic parts and relationships were the middle cranial fossa alignment and the mandibular corpus length relative to the maxilla. The most variable Class III anatomic relationships
were the ramus alignment and horizontal width of the ramus relative to the MCF dimension. The Class I subjects were similar to the Class III subjects in variability of the anatomic relationships with a variation of only 10% to 15% in all but two areas. The Class III sample had 25% more backward-positioned MCF than the Class I sample and 90% of the Class III subjects, from 9 years of age, exhibited a mandibular corpus longer than the maxillary corpus, as compared to only 70% of the Class I subjects. 3. The Class III sample exhibited a steady decrease in the number of different craniofacial compositions from 6 to 16+ years of age. In contrast, the Class I sample maintained a high level of different craniofacial compositions throughout the same time period. However, both groups did express a pubertal growth spurt, reflected in the significant increase in variability among the anatomical relationships between the age levels of 9 and 14 years. 4. In the Class III group, the combination of anatomic relationships (including the middle cranial fossa alignment, mandibular corpus length relative to maxilla, ramus horizontal width relative to MCF, and the gonial angle) exhibited a pattern stability of 78% at the g-year level and a 90% stability at the 1Cyear level. The Class I anatomic combinations were too variable to predict higher than 50%. These levels of prediction confidence are for this sample. Further research is needed to determine confidence levels in other samples. Information from Whitney (1983) on a sample of 20 skeletal Class II subjects analyzed in a similar manner was compared to the Class III and Class I data from this study. Following is a summary of the results of this comparison. 1. The Class II 16-year-old sample consisted of 6 different craniofacial compositions with 4 different subtypes, demonstrating a Class II malocclusion. 2. The middle cranial fossa alignment and mandibular corpus length relative to the maxilla was very stable in the Class III sample and extremely variable in the Class II pattern. 3. The Class II sample exhibited a steady increase in the number of different craniofacial compositions, even after 14 years of age. This is contrary to the Class III sample which showed a steady decrease in the number of compositions, especially after the 16year level. The Class I sample did not fluctuate. It maintained instead a significant number of different craniofacial compositions. The overall results from this study and the Class II comparison are summarized as follows: 1. The Class III craniofacial complex exhibited a large amount of change early in development and main-
86
Reviews
and
Sm. J. Onhod. Irrlv 1985
abstracts
tained it partly through puberty. The craniofacial pattern then appeared to undergo only refinements, not total architectural turnover. 2. The Class II craniofacial complex showed less change early in development, but significant increases in the number of changes from a period beginning before puberty and continuing to late adolescence. Many portions of the Class II craniofacial pattern appeared to change at all age levels, as reflected by the large number of individual counterpart changes for each age level. 3. The Class I sample showed Class II tendencies in some anatomic parts and relationships and Class III tendencies in others. It appears from this study that Class I subjects do not constitute a separate dental classification but, rather, a craniofacial composition that has balanced or compensated for the various maxillary and mandibular protrusive tendencies within their present craniofacial complexes. Changes in Synovial Fluid Pressure Altered Mandibular Positions Dennis M. Ward Case Western
Reserve
University,
Cleveland,
Ohio,
due to
1984
The role of the synovial organ in relation to joints other than the temporomandibular has long been investigated. Its responsibilities include nutrition and lubrication to the articular surfaces. The pressure of the synovial fluid has been measured in both long-bone joints and, recently, TMJ’s. Both have demonstrated negative pressure relative to the atmosphere. It is conceivable that changes in mandibular position could have marked effects on the relative pressure of the synovial fluid. This study was designed to measure the synovial fluid pressure in the growing animal, uninhibited by mechanical intervention and by change of the mandibular position. Various functional parameters were investigated including mastication, lateral movements, and opening and closing of the mandible. The resting synovial fluid pressure was found to be subatmospheric in the unaltered TMJ. By functionally positioning the mandible forward, there was a marked rise in pressure with a gradual stabilization and return to the baseline level. With a retruding appliance in place, the synovial fluid pressure increased substantially and failed to return to a subatmospheric level for the duration of the experiment. The fluctuation in synovial fluid pressure could have biologic implications with respect to its role in nutrition and lubrication. Elevated pressures could cause local ischemic changes and decreased lubrication with increased friction to the articular surfaces.
Synovial fluid may be the medium by which pressure changes caused by altered mandibular position are translated to joint surfaces. The findings are summarized as follows: 1. The resting synovial fluid pressure was negative relative to the atmosphere in all 6 joints. The mean value was -3.9 mm Hg. 2. Pressure increased during operator-manipulated jaw positions. When the jaw was released, the pressure returned to the baseline. 3. There was a marked increase in pressure when a protruding appliance was in place. This pressure gradually returned to the baseline. The return was attributed to joint compliance and absorption of fluid. 4. There was a substantial rise in pressure when a retruding appliance was in place. The pressure did not return to the baseline. 5. Mastication produced a marked pressure change. The pressure changes appeared cyclic. 6. Possible relations between fluid pressure/pathosis and growth development were discussed. The hbasurement of Changes in Oxygen Concentration, Redox Potential, pcI, and Temperature in the Periodontal Membrane During Force Application Ira Harold Weiss Case Western
Reserve
University,
Cleveland,
Ohio,
1984
This study dealt with the biologic responses of the tooth-supporting apparatus to an application of force of sudden onset and short duration. The four parameters selected were believed to be especially sensitive to significant changes in tissue respiration and energy-dependent biochemical reactions. The parameters selected for evaluation during force application were oxygen tension, redox potential, pH, and temperature. All of these factors are extremely important in a consideration of any biochemical reaction or chain of reactions that requires energy or liberates energy. Electrodes and companion measurement systems were designed, tested, and applied to an in vivo model. Two animal systems were used. One consisted of the anterior maxillary dental incisors of male hamsters. The periodontal membrane in these teeth was reasonably wide and the bone sufficiently elastic to allow the insertion of extremely thin redox-sensing electrodes. The second animal model was the mandibular premolar teeth in a female dog. This model permitted the application of calibrated forces and allowed access to the periodontal membrane via two approaches: (1) an apicoectomy in the area of the distal root of the man-