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The effect of maxillary surgery on respiration
188
Reviews and abstracts
for each of the cases and for each of the orthodontists. The results showed a marked variation among the orthodontists in the pattern of proportion of agreement to the diagnostic standard. Overall, in a significant proportion of cases (55%), study models alone provided adequate information for treatment planning, and incremental addition of diagnostic records made small differences. To assess the orthodontists' consistency of treatment decision making, given the same number of records over a period of time, session 5 was repeated on 15 cases after 4 to 6 weeks. The proportion of consistent treatment plan decisions made over a period of 4 to 6 weeks ranged from 53% to 73%, with an average of 65%. From this study, the following conclusions might be drawn: 1. The treatment planning decisions of the cases varied significantly among the clinicians (i.e., the recommended treatment plans were heterogeneous among the clinicians). 2. There was a significant variation among the orthodontists with respect to the pattern of treatment decision making relative to diagnostic records. 3. The intraclinician consistency of treatment decisions made over a period of time, given the same number of records also varied among the clinicians. 4. The method of studying the consistency of orthodontic treatment decisions was shown to be reliable. 5. With the use of this model of decision-making process, in a significant proportion of cases, study models alone provided adequate information for treatment planning and incremental addition of diagnostic records made small differences.
Am. g. Orthod. Dentofac. Orlhop. February 1991
protrusive appliance could synergistically increase condylar or mandibular growth. Ninety preadolescent 28-day-old male SpragueDawley rats were divided into six experimental groups (n = 5 each) for three different time intervals. The animals were killed at 3, 7, and 14 days. The six groups were (1) PEMF (high magnetic, low electric field) + protrusive appliance; (2) PEMF (low magnetic, high electric field) + protrusive appliance; (3) PEMF (high magnetic, low electric field) only; (4) PEMF (low magnetic, high electric field) only; (5) protrusive appliance only; and (6) home cage control. Animals were placed in the PEMF for 8 hours/day, and those wearing protrusive appliances wore them full time. Rats were injected with tritiated proline initially and were injected again with tritiated proline and thymidine 1 hour before being killed. Autoradiographic analysis included the following condylar measurements made on mid, anterior, and posterior coronal 5 I.tm sections: (1) heights of the articular, proliferative, hypertrophic, and maturational layers of condylar cartilage, (2) distance between labeled proline bands in osseous tissue, (3) number of thymidine labeled cells. Mandibular growth was assessed on lateral cephalograms of the 14-day groups, and the following measurements were made: mandibular length, mandibular height, and occlusal plane to mandibular plane angle. Results were statistically significant (by analysis of variance) for the variables of appliance and field. The protrusive appliance resulted in increases in body weight and in osseous matrix deposition and in decreases in the thickness of the condylar proliferative zone and in the maturation and hypertrophic zones. The effect of the higher electric field was positive on chondrogenic tissues in comparison to the higher magnetic field, which was observed to have a positive osteogenic effect. The effect seen in combining the protrusive appliances with the PEMFs was not synergistic for condylar or mandibular growth.
An analysis of the effects of PEMF stimulation and protrusive appliances on mandibular and condylar growth in juvenile rats Janice J. Wilmot
The effect of maxillary surgery on respiration Ronald R. Lints
Ann Arbor, Michigan: The University of Michigan, 1989
Ann Arbor, Michigan: The University of Michigan, 1989
Previous studies have described increased growth of mandibular condylar cartilage after pulsed electromagnetic field (PEMF) stimulation, while other studies have shown increased condylar growth in rats wearing protrusive appliances. The aim of this study was to determine whether PEMF stimulation combined with a
In the past, marly orthodontic studies have attempted to evaluate the relationship between function and form of the craniofacial complex and to base their rationale on the premise that function alters form. This prospective study was planned to evaluate the extent to which altered form changes function. When surgeons
Volume 99 Number 2
change the position of the maxilla relative to the cranial base and alter the nasopharyngeal airway, changes in respiratory function may occur. Morphologic changes induced by surgery may include alteration of the bony walls of the maxilla, manipulation of the nasal septum, removal of the inferior turbinates, and alteration of the shape of the liminal valve. The specific purpose of this thesis is to evaluate the influence of maxillary surgery on both nasal resistance to respiratory airflow and percent nasal respiration relative to total respiration. Correlating these respiratory parameters with morphologic changes due to surgery can provide insights into the form/function interaction and the adaptive mechanisms of the craniofacial complex. The sample consisted of 36 maxillary surgery patients ranging in age from 13 to 42 years, with a mean age of 23.2 years, obtained from the dentofacial program and the Department of Oral and Maxillofacial Surgery at the University of Michigan School of Dentistry. Of the 36 patients who underwent maxillary surgery, 28 had impaction of the maxilla with or without anterior movement, one had a maxillary setback, and seven had maxillary advancement. Respiratory function was tested before surgery and 1 year after surgery. Results indicated that associations between the amount of vertical movement of the maxilla and the change in respiratory values were weak. The correlations between the horizontal change in the maxilla and respiratory changes were small. Presurgical and postsurgical respiration parameters (nasal resistance and percent nasal respiration) had weak association with the anteroposterior dimensions of the nasopharynx. No cor-
Reviews and abstracts
189
relations reached a level of significance at p < 0.05. Small and insignificant correlations were found between respiration change, and the change in nasopharyngeal dimension resulting from surgery. Furthermore, this study found little correlation, either presurgically or postsurgically, between respiration and vertical dimensions (facial height or lip separation) of the total sample. Change in nasopharyngeal depth was strongly associated with the change in the horizontal position of the maxilla. However, the change in the airways determined by the previously described cephalometric points had weak correlations. It was concluded that (1) Because of the variability of respiratory response after maxillary surgery, predicting increase in nasal respiration of an individual is not supported; (2) the mean change in respiration after maxillary surgery tended to decrease for nasal resistance and not change for percent nasal respiration (the volume of air breathed through the nose over the total volume of air breathed); (3) use of a lateral cephalogram as a diagnostic aid to assess nasopharyngeal airway and respiratory function is not supported and may lead to unnecessary surgery suggested for respiratory benefits; (4) lip separation and vertical facial height as indicators of respiratory function are unreliable; (5) the variability of nasopharyngeal soft tissue positional change due to maxillary surgery is large, which precludes predictions of airway change after surgery; and (6) the position of the maxilla relative to cranial base does not seem to be an important factor in determining nasopharyngeal depth.
Reviews and abstracts
for each of the cases and for each of the orthodontists. The results showed a marked variation among the orthodontists in the pattern of proportion of agreement to the diagnostic standard. Overall, in a significant proportion of cases (55%), study models alone provided adequate information for treatment planning, and incremental addition of diagnostic records made small differences. To assess the orthodontists' consistency of treatment decision making, given the same number of records over a period of time, session 5 was repeated on 15 cases after 4 to 6 weeks. The proportion of consistent treatment plan decisions made over a period of 4 to 6 weeks ranged from 53% to 73%, with an average of 65%. From this study, the following conclusions might be drawn: 1. The treatment planning decisions of the cases varied significantly among the clinicians (i.e., the recommended treatment plans were heterogeneous among the clinicians). 2. There was a significant variation among the orthodontists with respect to the pattern of treatment decision making relative to diagnostic records. 3. The intraclinician consistency of treatment decisions made over a period of time, given the same number of records also varied among the clinicians. 4. The method of studying the consistency of orthodontic treatment decisions was shown to be reliable. 5. With the use of this model of decision-making process, in a significant proportion of cases, study models alone provided adequate information for treatment planning and incremental addition of diagnostic records made small differences.
Am. g. Orthod. Dentofac. Orlhop. February 1991
protrusive appliance could synergistically increase condylar or mandibular growth. Ninety preadolescent 28-day-old male SpragueDawley rats were divided into six experimental groups (n = 5 each) for three different time intervals. The animals were killed at 3, 7, and 14 days. The six groups were (1) PEMF (high magnetic, low electric field) + protrusive appliance; (2) PEMF (low magnetic, high electric field) + protrusive appliance; (3) PEMF (high magnetic, low electric field) only; (4) PEMF (low magnetic, high electric field) only; (5) protrusive appliance only; and (6) home cage control. Animals were placed in the PEMF for 8 hours/day, and those wearing protrusive appliances wore them full time. Rats were injected with tritiated proline initially and were injected again with tritiated proline and thymidine 1 hour before being killed. Autoradiographic analysis included the following condylar measurements made on mid, anterior, and posterior coronal 5 I.tm sections: (1) heights of the articular, proliferative, hypertrophic, and maturational layers of condylar cartilage, (2) distance between labeled proline bands in osseous tissue, (3) number of thymidine labeled cells. Mandibular growth was assessed on lateral cephalograms of the 14-day groups, and the following measurements were made: mandibular length, mandibular height, and occlusal plane to mandibular plane angle. Results were statistically significant (by analysis of variance) for the variables of appliance and field. The protrusive appliance resulted in increases in body weight and in osseous matrix deposition and in decreases in the thickness of the condylar proliferative zone and in the maturation and hypertrophic zones. The effect of the higher electric field was positive on chondrogenic tissues in comparison to the higher magnetic field, which was observed to have a positive osteogenic effect. The effect seen in combining the protrusive appliances with the PEMFs was not synergistic for condylar or mandibular growth.
An analysis of the effects of PEMF stimulation and protrusive appliances on mandibular and condylar growth in juvenile rats Janice J. Wilmot
The effect of maxillary surgery on respiration Ronald R. Lints
Ann Arbor, Michigan: The University of Michigan, 1989
Ann Arbor, Michigan: The University of Michigan, 1989
Previous studies have described increased growth of mandibular condylar cartilage after pulsed electromagnetic field (PEMF) stimulation, while other studies have shown increased condylar growth in rats wearing protrusive appliances. The aim of this study was to determine whether PEMF stimulation combined with a
In the past, marly orthodontic studies have attempted to evaluate the relationship between function and form of the craniofacial complex and to base their rationale on the premise that function alters form. This prospective study was planned to evaluate the extent to which altered form changes function. When surgeons
Volume 99 Number 2
change the position of the maxilla relative to the cranial base and alter the nasopharyngeal airway, changes in respiratory function may occur. Morphologic changes induced by surgery may include alteration of the bony walls of the maxilla, manipulation of the nasal septum, removal of the inferior turbinates, and alteration of the shape of the liminal valve. The specific purpose of this thesis is to evaluate the influence of maxillary surgery on both nasal resistance to respiratory airflow and percent nasal respiration relative to total respiration. Correlating these respiratory parameters with morphologic changes due to surgery can provide insights into the form/function interaction and the adaptive mechanisms of the craniofacial complex. The sample consisted of 36 maxillary surgery patients ranging in age from 13 to 42 years, with a mean age of 23.2 years, obtained from the dentofacial program and the Department of Oral and Maxillofacial Surgery at the University of Michigan School of Dentistry. Of the 36 patients who underwent maxillary surgery, 28 had impaction of the maxilla with or without anterior movement, one had a maxillary setback, and seven had maxillary advancement. Respiratory function was tested before surgery and 1 year after surgery. Results indicated that associations between the amount of vertical movement of the maxilla and the change in respiratory values were weak. The correlations between the horizontal change in the maxilla and respiratory changes were small. Presurgical and postsurgical respiration parameters (nasal resistance and percent nasal respiration) had weak association with the anteroposterior dimensions of the nasopharynx. No cor-
Reviews and abstracts
189
relations reached a level of significance at p < 0.05. Small and insignificant correlations were found between respiration change, and the change in nasopharyngeal dimension resulting from surgery. Furthermore, this study found little correlation, either presurgically or postsurgically, between respiration and vertical dimensions (facial height or lip separation) of the total sample. Change in nasopharyngeal depth was strongly associated with the change in the horizontal position of the maxilla. However, the change in the airways determined by the previously described cephalometric points had weak correlations. It was concluded that (1) Because of the variability of respiratory response after maxillary surgery, predicting increase in nasal respiration of an individual is not supported; (2) the mean change in respiration after maxillary surgery tended to decrease for nasal resistance and not change for percent nasal respiration (the volume of air breathed through the nose over the total volume of air breathed); (3) use of a lateral cephalogram as a diagnostic aid to assess nasopharyngeal airway and respiratory function is not supported and may lead to unnecessary surgery suggested for respiratory benefits; (4) lip separation and vertical facial height as indicators of respiratory function are unreliable; (5) the variability of nasopharyngeal soft tissue positional change due to maxillary surgery is large, which precludes predictions of airway change after surgery; and (6) the position of the maxilla relative to cranial base does not seem to be an important factor in determining nasopharyngeal depth.