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Enamel demineralization: A sequelae of pH and molarity changes
Reviews and abstracts
sue, cell, and molecular levels. These differences account, indeed, for the level of mandibular “growth potential” and “responsiveness” (i.e., for the degree of effectiveness of functional appliances .) The cybernetic approach to facial growth contributed to the elaboration of a biologically and cephalometrically based procedure in orthodontic decision making. This procedure, using a new classification of facial growth rotations, leads to the indirect identification of the level of mandibular “growth potential” and “responsiveness .” The fact is that these biologic features of mandibular tissues are essential for the selection of the most appropriate treatment of skeletal malrelations and dental malocclusions. Alex Jacobson
~ol~gical Evaluation of the Effects of ognathic Surgery for Male and Female nts With Mandibular Prognathism corner Itok, Shoko and Hideo Mitani J. Jpn.
&hod.
Sot.
Yamakage,
Yasuko
Endo,
1988;47:601-11
This study evaluated sex differences in psychological effects between male and female patients who underwent orthognathic surgery for correction of mandibular prognathism. Materials consisted of 14 male and 16 female patients, ail with diagnoses of severe mandibular prognathism before surgery. Evaluation was made at preoperative and postoperative stages by means of the ~atabe-Guilford Personality Inventory Test and a questionnaire especially designed for this study. The questionnaire was composed of 20 items concerning facial esthetics and oral functions and was statistically analyzed by factor analysis. The foolowing results were obtained: 1. In both sexes, the mean profile of the scale and factor values of the Y-G test indicated that the patients obtained higher emotional stability and extraversion after operation. However, the changes occurred more sig~ifica~tly in females than in males. 2. The questionnaire test showed that, at the preoperative stage, males had a greater inferiority complex to oral functional factors and that females had it to esthetic factors. The test also showed that this was improved after surgery. The study concluded that orthognathic surgery for mandibular prognathism caused psychological effects in patients, but the effects were different between male and female patients. Males related more to the effects
for social problems; females related to those for selfinternal emotional problems. Alex Jacobson
Thesis abstracts Enamel Demineralization: pH and Molarity Changes G. Kirkland Washington, Orthodorztic
and N. Soni D.C.: Howard University, Department, 1988
CoElege
qf Deniistry,
Forty-four extracted first premolar teeth received bondable orthodontic brackets and were submerged in one of the prepared acidic buffers. The buffers were citrate and acetate at 4.5 and 5 .O pH witb concentrations of 0.1, 0.01, and 0.001 M. The teeth remained in solution until there was clinical evidence of white spot formation, at which time the teeth were removed from the solution. Twelve of the teeth in the most concentrated solutions remained in solution until the teeth in the least concentrated solutions had white spot formation. Five milliliter aliquots of the used buffer solution were removed so that calcium and phosphate quantitation could be performed using the Automated Astra Instrumentation. The demineralized tooth was sectioned leaving only the buccal surface, which was analyzed under the scanning electron microscope. The bracket was removed from some of the teeth to compare the exposed to the unexposed tooth surfaces. Nonparametric statistical analyses were used to assess the data because of the small sample size. The initial day of demineralization for all 0.1 samples was at 2 days, at 5 days for all 0.0 1 M samples, and at 6 days for all 0.001 M samples. By means of the Mann-Whitney U test, it was determined that neither differing pH nor differing buffer when other variables were constant was statistically significant at or less than the 0.05 probability level. Comparison of the mineral loss between the most concentrated and the least concentrated solutions after 6 days was statistically significant at and less than the 0.05 probability level. Calcium loss with citrate buffer after 6 days at 0.1 M ranged from 10 to 15 times more than the loss at 0.001 M. The Kruskal-Wallis II test did not find the values for the three differing molarities to be statistically significant at or less than the 0.05 probability level, but it was significant for calcium at the 0.08 probability level.
Volume 96 Number 4
Reviews
Scanning electron microscopic studies showed three types of surface lesion: (1) multiple areas of cavitation along the enamel surface, although clinically no cavitations were visible, (2) partial destruction of surface enamel giving the irregular “overetched” appearance with minimal evidence of cavitation, and (3) prismatic pattern of destruction of surface enamel. The unexposed, protected enamel beneath the bracket more closely approximated the “normal” enamel surface than $he surfaces directly exposed to acid.
The Hyoid Bone Position in Mouth : Cross-Sectional Study reath J. Tu~~kin Washington, Orthodonfic
and E. Kudlick D.C.: Howard University, Department, 1987
College
of Dentistry,
A sample of the records of 66 patients (33 male and 33 female patients) was taken from the Orthodontic Clinic of Howard University College of Dentistrv. The
AA0
MEETING
und
abstracts
type of breather was determined during the gatient’s initial clinical examination. Acetate tracing paper was placed over lateral and frontal radiographs to measure the mandibular plane angle, diameter of the posterior turbinates, deviation of the nasal septum, protuberance of the adenoid tissue, airway, head posture, and the vertical and horizontal distances between the hyoid bone to epiglottis and genial tubercules. The purpose of this study was to evaluate patients who were mouth breathers and nasal breathers to determine whether there were any significant differences between the two groups when comparing mandibular growth patterns and the position of the hyoid bone to the epiglottis and the genial tubercules of the mandible. The conclusions drawn from this study suggested that impedance of the functional airway was associated with high mandibular plane angles, a decrease in horizontal distance between the hyoid bone and epiglottis, and a decrease in horizontal distance between the hyoid bone and genial tubercules.
CALENDAR
1990-Washington, D.C., May 6 to 9, Washington Convention Center 1991 -Seattle, Wash., May 12 to 15, Seattle Convention Center 1992-St. Louis, MO., May 10 to 13, St. Louis Convention Center 1993-Toronto, Canada, May 16 to 19, Metropolitan Toronto Convention Center 1994-Orlando, Fla., May 1 to 4, Orange County Convention and Civic Center 1995-San Francisco, Calif., May 7 to 10, Moscone Convention Center 1996-New York, N.Y., April 21 to 24, Javits Convention Center
sue, cell, and molecular levels. These differences account, indeed, for the level of mandibular “growth potential” and “responsiveness” (i.e., for the degree of effectiveness of functional appliances .) The cybernetic approach to facial growth contributed to the elaboration of a biologically and cephalometrically based procedure in orthodontic decision making. This procedure, using a new classification of facial growth rotations, leads to the indirect identification of the level of mandibular “growth potential” and “responsiveness .” The fact is that these biologic features of mandibular tissues are essential for the selection of the most appropriate treatment of skeletal malrelations and dental malocclusions. Alex Jacobson
~ol~gical Evaluation of the Effects of ognathic Surgery for Male and Female nts With Mandibular Prognathism corner Itok, Shoko and Hideo Mitani J. Jpn.
&hod.
Sot.
Yamakage,
Yasuko
Endo,
1988;47:601-11
This study evaluated sex differences in psychological effects between male and female patients who underwent orthognathic surgery for correction of mandibular prognathism. Materials consisted of 14 male and 16 female patients, ail with diagnoses of severe mandibular prognathism before surgery. Evaluation was made at preoperative and postoperative stages by means of the ~atabe-Guilford Personality Inventory Test and a questionnaire especially designed for this study. The questionnaire was composed of 20 items concerning facial esthetics and oral functions and was statistically analyzed by factor analysis. The foolowing results were obtained: 1. In both sexes, the mean profile of the scale and factor values of the Y-G test indicated that the patients obtained higher emotional stability and extraversion after operation. However, the changes occurred more sig~ifica~tly in females than in males. 2. The questionnaire test showed that, at the preoperative stage, males had a greater inferiority complex to oral functional factors and that females had it to esthetic factors. The test also showed that this was improved after surgery. The study concluded that orthognathic surgery for mandibular prognathism caused psychological effects in patients, but the effects were different between male and female patients. Males related more to the effects
for social problems; females related to those for selfinternal emotional problems. Alex Jacobson
Thesis abstracts Enamel Demineralization: pH and Molarity Changes G. Kirkland Washington, Orthodorztic
and N. Soni D.C.: Howard University, Department, 1988
CoElege
qf Deniistry,
Forty-four extracted first premolar teeth received bondable orthodontic brackets and were submerged in one of the prepared acidic buffers. The buffers were citrate and acetate at 4.5 and 5 .O pH witb concentrations of 0.1, 0.01, and 0.001 M. The teeth remained in solution until there was clinical evidence of white spot formation, at which time the teeth were removed from the solution. Twelve of the teeth in the most concentrated solutions remained in solution until the teeth in the least concentrated solutions had white spot formation. Five milliliter aliquots of the used buffer solution were removed so that calcium and phosphate quantitation could be performed using the Automated Astra Instrumentation. The demineralized tooth was sectioned leaving only the buccal surface, which was analyzed under the scanning electron microscope. The bracket was removed from some of the teeth to compare the exposed to the unexposed tooth surfaces. Nonparametric statistical analyses were used to assess the data because of the small sample size. The initial day of demineralization for all 0.1 samples was at 2 days, at 5 days for all 0.0 1 M samples, and at 6 days for all 0.001 M samples. By means of the Mann-Whitney U test, it was determined that neither differing pH nor differing buffer when other variables were constant was statistically significant at or less than the 0.05 probability level. Comparison of the mineral loss between the most concentrated and the least concentrated solutions after 6 days was statistically significant at and less than the 0.05 probability level. Calcium loss with citrate buffer after 6 days at 0.1 M ranged from 10 to 15 times more than the loss at 0.001 M. The Kruskal-Wallis II test did not find the values for the three differing molarities to be statistically significant at or less than the 0.05 probability level, but it was significant for calcium at the 0.08 probability level.
Volume 96 Number 4
Reviews
Scanning electron microscopic studies showed three types of surface lesion: (1) multiple areas of cavitation along the enamel surface, although clinically no cavitations were visible, (2) partial destruction of surface enamel giving the irregular “overetched” appearance with minimal evidence of cavitation, and (3) prismatic pattern of destruction of surface enamel. The unexposed, protected enamel beneath the bracket more closely approximated the “normal” enamel surface than $he surfaces directly exposed to acid.
The Hyoid Bone Position in Mouth : Cross-Sectional Study reath J. Tu~~kin Washington, Orthodonfic
and E. Kudlick D.C.: Howard University, Department, 1987
College
of Dentistry,
A sample of the records of 66 patients (33 male and 33 female patients) was taken from the Orthodontic Clinic of Howard University College of Dentistrv. The
AA0
MEETING
und
abstracts
type of breather was determined during the gatient’s initial clinical examination. Acetate tracing paper was placed over lateral and frontal radiographs to measure the mandibular plane angle, diameter of the posterior turbinates, deviation of the nasal septum, protuberance of the adenoid tissue, airway, head posture, and the vertical and horizontal distances between the hyoid bone to epiglottis and genial tubercules. The purpose of this study was to evaluate patients who were mouth breathers and nasal breathers to determine whether there were any significant differences between the two groups when comparing mandibular growth patterns and the position of the hyoid bone to the epiglottis and the genial tubercules of the mandible. The conclusions drawn from this study suggested that impedance of the functional airway was associated with high mandibular plane angles, a decrease in horizontal distance between the hyoid bone and epiglottis, and a decrease in horizontal distance between the hyoid bone and genial tubercules.
CALENDAR
1990-Washington, D.C., May 6 to 9, Washington Convention Center 1991 -Seattle, Wash., May 12 to 15, Seattle Convention Center 1992-St. Louis, MO., May 10 to 13, St. Louis Convention Center 1993-Toronto, Canada, May 16 to 19, Metropolitan Toronto Convention Center 1994-Orlando, Fla., May 1 to 4, Orange County Convention and Civic Center 1995-San Francisco, Calif., May 7 to 10, Moscone Convention Center 1996-New York, N.Y., April 21 to 24, Javits Convention Center