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Clinical considerations in extraction decisions
American Journal of Orthodontics and Dentofacial Orthopedics
Reviews and abstracts
391
Volume 103, No. 4
The effects of transforming growth factor-I~ (TGF-13) on intracellular calcium in osteoblastlike clone cells MC3T3-E1. A. D. Mau, San Francisco, California: University of Pacific, School of Dentistry, 1991
In this study transforming growth factor-J3 was introduced to the osteoblastic cell line MC3T3-EI to evaluate how this growth factor influenced the intracel[ular calcium of these cells. The aequorin scrape-loading technique was employed to measure cytosolic calcium concentrations. The intracellular calcium concentrations were recorded before the growth factor was introduced to the cells and after four separate and different doses were perfused through the cells. The doses of TGF-I3 were; 0.2 ng/ml, 1.0 ng/ml, 2.0 ng/ml, and 10.0 ng/ml. A Student t test revealed that TGF-[3 caused statistically significant increase intracellular calcium except for the 0.2 ng/ml dose. A correlation curve was established and it was conchtded that transforming growth factor-J3 does hzfl,rence cytosol!c calcium in MC3T3-E1 cell Ihre in a dose dependent maturer.
The effects of unilateral cervical sympathectomy on mandibular growth in
young rats. C. R. Chan, San Francisco, California: Universit'j" of the Pacific, School of Dentistry, 1991
The effects of sympathetic denervation on mandibular growth after unilateral superior cervical ganglionectomy was evaluated in 24 growing Sprague-Dawley rats. The animals were divided into three groups: experimental, sham control, and control animals. Mandibular morphology and growth was evaluated using qualitative (microscopic) and quantitative analyses. Vital osteogenic bone labels were used to analyze mandibular growth including: length, height, width, and rate of growth. Our results indicated that sympathetic denervation did not affect growth of the mandible anteroposteriorly or in the vertical dimension. Sympathetic denervation also did not influence mandibular width changes or rate of growth. Tire conclusion that sympathetic neurotrophism contributes a major factor hz the regulation of craniofacial growth cannot be supported.
Immunohistochemistry of the binding of monoclonal antibody to Ca *2 Mg § ATPase in rat alveolar bone cells during unimpeded tooth movement. N. Warshawsky, A. E. Zaki, and J. L. Borke, Cl, icago: University of lllhzois and Loyola University School of Dental Medichze, 1992 The purpose of this study was to examine the binding of monoclonal anticalcium pump antibody to rat alveolar bone cells during increased bone activity. Twelve rats of 125 to 150 gm were anesthetized, and the right maxillary first molar was extracted to encourage unimpeded eruption of the opposing teeth. Rats were killed 1, 6, 24, and 48 hours after extraction witli an ether overdose and intracardially perfused. Maxillae were dissected out, and the molars were removed
en bloc along with a coronal section through the growing end of the mandibular incisor. After fixation, the tissue was demineralized and sectioned approximately 4 i.tm thick. Sections were cut at the level of the bifurcation of the molar roots, 100 p.m, and 200 tim deeper and mounted on glass slides that had sections of secretory ameloblasts previously mounted on them. Sections were immunohistochemically incubated for antigens specific to 5f10, an antibody specific for the calcium pump prepared from human erythrocytes. Tissue was incubated in an avidin-biotin complex followed by 3,3'diaminobenzidine tetrahydrochloride (DAB). Stained slides where then counterstained with Mayer's hemotoxylin. Controls included cold sections without the antibody as well as sections of secretory ameloblasts, positive for this staining reaction. Histologic results showed an increase in the rate of distobuccal drift of all right mandibular molars. The effects were most notable for the mandibular first molars. An increased number of osteoclasts were seen with time on the alveolar bone surface facing the distal root surfaces. The PDL showed signs of hyalinization after 24 hours after extraction. Immunohistochemical results showed an inconsistent number of osteoclasts opposing the distal surface of the root with staining along their membrane from the marker. The occurrence was greatest 48 hours after extraction. Some of the blood elements within the, bone marrow also consistently stained for the 5f10 marker, regardless of whether or not extraction was performed. By using imnnmohistochemical techniques an epitope of the human e~'throcyte plasma tnenrbrane Ca +§ pump was observed along the cell membrane of the rat osteoclast. Its presence was linked in a time dependent manner to increased physiologic drift of the mandibular molars. Tire sporadic presence of the binding of this antibody to osteoclasts imply that this protehr may play a role in regulating the hltracelhdar calciun! concentration of the osteoclast, as well as its surrounding tnicroenvironment. The presence of this marker in hematopoietic tissue inthnates that a plasma membrane Ca § § pump may be present in some cells of the bone marrow, but the implications of this are trot well understood.
Clinical considerations in extraction decisions. B. L. Grey, San Francisco, California: University of the Pacific, School of Dentistry, 1991 The purpose of this study was to compare the rationale of the expert clinician in the orthodontic extraction decision with the traditional cephalometric and dental measures used in orthodontic diagnosis. Seventy-two cases from the University of the Pacific School of Dentistry Orthodontic Clinic were evaluated by five of a panel of nine clinicians as to the individual clinician's rationale for or against extraction. Both the clinician assessments and the objective variables were correlated with the degree to which extraction was preferred. The number and character of the clinical considerations did --not v.ary appreciably over the range of extractiveness of the sample. In addition, the correlations of the objective variables were strongest when the adolescent and adult samples were
392
Reviews and abstracts
separated. This was both in terms of magnitude and degree of concurrence with the cited clinical considerations.
Cytoplasmic pH influence on cytoplasmic calcium ions in osteoblat MC3T3-E1 cells. L. Heng-Sheng, San Francisco, California: University of the Pacific, School of Dentistry. 1991 IntracellularpH is important to most metabolic processes, and it might play a role in bone remodeling along with calcium. I investigated the possible roles of cytoplasmic calcium (Ca'-+~) and hydrogen ions (pH,) as second messengers in osteoblasts in the control of bone metabolism. To do this, I loaded the mouse osteoblastic-like cell MC3R3-EI with aequorin, a calcium-sensitive luminescent protein, and then entrapped the-cells in a flow-through cuvette of a photometer. I then exposed the cells to experimental conditions that are known to change pH~ to see if they also changed Ca2§ Ca~*~ incre~asedwhen the cytoplasm of these cells was made alkaline withleither the addition of NH,CI or by the reduction of CO2 in the presence of 24 rmM NaHCOj. Ca2§ decreased when the cytoplasm was made acidic by either the removal of NH~CI or the reduction of NaHCO2 with 5% pCO2. These effects were. completely reversible, reproducible, and dos e depen- 9 dent. These results suggest that physiologic changes in p H do contribute importantly to the cellular homeostasis of Ca'-* in osteoblast cells.
The effect of prostaglandln E= on intracellular pH in the osteoblastic clonal line MC3T3-E1 cells. S. E. Markowitz, San Francisco, California: Universiry of the Pacific, School of Dentistry, 1991 Prostaglandins (PGE2) have been shown to enhance orthodontic therapy by altering osteoblastic activity. We are interested in the possible roles of cytoplasmic calcium ions (Ca2*,) and hydrogen ions (pHi) as second messengers in the response of osteoblasts to PGE_, stimulation. To do this, we loaded mouse ostoblastic cells (MC3R3-EI) with aequorin (A Ca'-§ sensitive luminescent protein that is insensitive to changes in pHi) and then entrapped the cells in a flow-through cuvctte of a photometer. When we then exposed the ceils to 10 I-tm prostaglandin E2, we observed a rapid increase in Ca"-+ followed by a plateau level above basal. This plateau was maintained as long as PGE2 was present. These changes in Ca2§ evoked by PGE_, were not altered by amiloride, an inhibitor of the N a + / H + exchanger, suggesting that PGE2 does not change the pHi in the cells by altering the activity of the N a + / H + antiporter. The pH sensitive fluorescent probe BCECF also indicated no change in pHi in the presence of PGE2, independently confirming this fir~ding. These results suggest that prostaglandin E2 hzcreases C a 2*~ bat does not change pHi in activathtg osteoblastic cells.
Quantifying malocclusion: A comparison of two malocclusion indices. J. Drew, Son Francisco: "'University of the Pacific, School of Dentisto,, 1992 The purpose of this study is to evaluate two malocclusion indices, the handicapping labiolingual deviation index (HLD)
American Journal of Orthodontics and Dentofacial Orthopedics April 1993
and the modified ocelusal feature index (MOI), for reliability and correlation with a subjective evaluation of malocclusion severity by experts (orthodontic faculty). Pretreatment models and photographs of 30 cases, representing a wide spectrum of malocclusion severity, were evaluated by five orthodontic residents using each index. These same cases were evaluated subjectively, mild, moderate, or severe, by five experts (orthodontic faculty members). Interexaminer and intraexaminer reliability was calculated as was correlation between the index values and subjective values. The interexaminerreliability values were high. The experts value was 0.92. The residents HLD value was 0.94 and MOI value was 0.93. The correlation for intraexaminer reliability was also high at 0.92 (HLD) and 0.99 (MOI). The correlation values were 0.82 (HLD versus experts), 0.71 (MOI versus experts) and 0.68 (HLD versus MOI). htterexamhzer reliability values suggest that each hzdex can be used consistently. The two indices correlate modestly with each other. The HLD had a higher correlation than the MOI with the subjective evahtation by orthodontic facttlty experts.
Radiographic evaluation of TMJ pathology: Comparative study: tomography and panography..1. Irish and D. Hatcher, San Francisco: University of the Pacific, School of Dentistry, 1992
The objective of this study was to assess the ability of the panelipse to discern the information available from corrected tomograms for the evaluation of the temporomandibular joint. Key parameters examined include bony changes of the condyle and fossa, condyle position in the fossa, and condylar form. Records from 50 TMJ patients taken from the Center for Facial Pain, at the University of California, San Francisco, which included both corrected tomograms and panelipse x-ray films of each subject were evaluated. A method of quantitating the shape of the condyles, joint spaces, ramus lengths, and range of maximum opening were developed. Degenerative changes of the condyle and fossa were ranked by three examiners for the presence and severity of sclerosis, flattening, erosions, osteophytes, and subcondylar bone cysts. The examiners included an expert radiologist, an orthodontist who limits his practice to TMJ patients and a second-year orthodontic resident. Findings taken from each technique were compared with the alternate technique using correlation statistics. Examiner reliability was also evaluated. The following conclusions were drawn: 1. Weak correlations exist comparhlg degenerative bony change categories ushtg the two techniques. The recommendation that panoramic x-ray films are acceptable alternatives to corrected tomograms for evaluation of degenerative changes appears haphazard. Information gathered from corrected tomograms does not appear to be collaborated in the panelipse. 2. Condylar shape measttrements gathered front panoramic x-ray fihns in the ntethod used fit this study do not correlate well with the same findings determined front corrected tomograms. Use of these measurements appears to be without practical advantage.
Reviews and abstracts
391
Volume 103, No. 4
The effects of transforming growth factor-I~ (TGF-13) on intracellular calcium in osteoblastlike clone cells MC3T3-E1. A. D. Mau, San Francisco, California: University of Pacific, School of Dentistry, 1991
In this study transforming growth factor-J3 was introduced to the osteoblastic cell line MC3T3-EI to evaluate how this growth factor influenced the intracel[ular calcium of these cells. The aequorin scrape-loading technique was employed to measure cytosolic calcium concentrations. The intracellular calcium concentrations were recorded before the growth factor was introduced to the cells and after four separate and different doses were perfused through the cells. The doses of TGF-I3 were; 0.2 ng/ml, 1.0 ng/ml, 2.0 ng/ml, and 10.0 ng/ml. A Student t test revealed that TGF-[3 caused statistically significant increase intracellular calcium except for the 0.2 ng/ml dose. A correlation curve was established and it was conchtded that transforming growth factor-J3 does hzfl,rence cytosol!c calcium in MC3T3-E1 cell Ihre in a dose dependent maturer.
The effects of unilateral cervical sympathectomy on mandibular growth in
young rats. C. R. Chan, San Francisco, California: Universit'j" of the Pacific, School of Dentistry, 1991
The effects of sympathetic denervation on mandibular growth after unilateral superior cervical ganglionectomy was evaluated in 24 growing Sprague-Dawley rats. The animals were divided into three groups: experimental, sham control, and control animals. Mandibular morphology and growth was evaluated using qualitative (microscopic) and quantitative analyses. Vital osteogenic bone labels were used to analyze mandibular growth including: length, height, width, and rate of growth. Our results indicated that sympathetic denervation did not affect growth of the mandible anteroposteriorly or in the vertical dimension. Sympathetic denervation also did not influence mandibular width changes or rate of growth. Tire conclusion that sympathetic neurotrophism contributes a major factor hz the regulation of craniofacial growth cannot be supported.
Immunohistochemistry of the binding of monoclonal antibody to Ca *2 Mg § ATPase in rat alveolar bone cells during unimpeded tooth movement. N. Warshawsky, A. E. Zaki, and J. L. Borke, Cl, icago: University of lllhzois and Loyola University School of Dental Medichze, 1992 The purpose of this study was to examine the binding of monoclonal anticalcium pump antibody to rat alveolar bone cells during increased bone activity. Twelve rats of 125 to 150 gm were anesthetized, and the right maxillary first molar was extracted to encourage unimpeded eruption of the opposing teeth. Rats were killed 1, 6, 24, and 48 hours after extraction witli an ether overdose and intracardially perfused. Maxillae were dissected out, and the molars were removed
en bloc along with a coronal section through the growing end of the mandibular incisor. After fixation, the tissue was demineralized and sectioned approximately 4 i.tm thick. Sections were cut at the level of the bifurcation of the molar roots, 100 p.m, and 200 tim deeper and mounted on glass slides that had sections of secretory ameloblasts previously mounted on them. Sections were immunohistochemically incubated for antigens specific to 5f10, an antibody specific for the calcium pump prepared from human erythrocytes. Tissue was incubated in an avidin-biotin complex followed by 3,3'diaminobenzidine tetrahydrochloride (DAB). Stained slides where then counterstained with Mayer's hemotoxylin. Controls included cold sections without the antibody as well as sections of secretory ameloblasts, positive for this staining reaction. Histologic results showed an increase in the rate of distobuccal drift of all right mandibular molars. The effects were most notable for the mandibular first molars. An increased number of osteoclasts were seen with time on the alveolar bone surface facing the distal root surfaces. The PDL showed signs of hyalinization after 24 hours after extraction. Immunohistochemical results showed an inconsistent number of osteoclasts opposing the distal surface of the root with staining along their membrane from the marker. The occurrence was greatest 48 hours after extraction. Some of the blood elements within the, bone marrow also consistently stained for the 5f10 marker, regardless of whether or not extraction was performed. By using imnnmohistochemical techniques an epitope of the human e~'throcyte plasma tnenrbrane Ca +§ pump was observed along the cell membrane of the rat osteoclast. Its presence was linked in a time dependent manner to increased physiologic drift of the mandibular molars. Tire sporadic presence of the binding of this antibody to osteoclasts imply that this protehr may play a role in regulating the hltracelhdar calciun! concentration of the osteoclast, as well as its surrounding tnicroenvironment. The presence of this marker in hematopoietic tissue inthnates that a plasma membrane Ca § § pump may be present in some cells of the bone marrow, but the implications of this are trot well understood.
Clinical considerations in extraction decisions. B. L. Grey, San Francisco, California: University of the Pacific, School of Dentistry, 1991 The purpose of this study was to compare the rationale of the expert clinician in the orthodontic extraction decision with the traditional cephalometric and dental measures used in orthodontic diagnosis. Seventy-two cases from the University of the Pacific School of Dentistry Orthodontic Clinic were evaluated by five of a panel of nine clinicians as to the individual clinician's rationale for or against extraction. Both the clinician assessments and the objective variables were correlated with the degree to which extraction was preferred. The number and character of the clinical considerations did --not v.ary appreciably over the range of extractiveness of the sample. In addition, the correlations of the objective variables were strongest when the adolescent and adult samples were
392
Reviews and abstracts
separated. This was both in terms of magnitude and degree of concurrence with the cited clinical considerations.
Cytoplasmic pH influence on cytoplasmic calcium ions in osteoblat MC3T3-E1 cells. L. Heng-Sheng, San Francisco, California: University of the Pacific, School of Dentistry. 1991 IntracellularpH is important to most metabolic processes, and it might play a role in bone remodeling along with calcium. I investigated the possible roles of cytoplasmic calcium (Ca'-+~) and hydrogen ions (pH,) as second messengers in osteoblasts in the control of bone metabolism. To do this, I loaded the mouse osteoblastic-like cell MC3R3-EI with aequorin, a calcium-sensitive luminescent protein, and then entrapped the-cells in a flow-through cuvette of a photometer. I then exposed the cells to experimental conditions that are known to change pH~ to see if they also changed Ca2§ Ca~*~ incre~asedwhen the cytoplasm of these cells was made alkaline withleither the addition of NH,CI or by the reduction of CO2 in the presence of 24 rmM NaHCOj. Ca2§ decreased when the cytoplasm was made acidic by either the removal of NH~CI or the reduction of NaHCO2 with 5% pCO2. These effects were. completely reversible, reproducible, and dos e depen- 9 dent. These results suggest that physiologic changes in p H do contribute importantly to the cellular homeostasis of Ca'-* in osteoblast cells.
The effect of prostaglandln E= on intracellular pH in the osteoblastic clonal line MC3T3-E1 cells. S. E. Markowitz, San Francisco, California: Universiry of the Pacific, School of Dentistry, 1991 Prostaglandins (PGE2) have been shown to enhance orthodontic therapy by altering osteoblastic activity. We are interested in the possible roles of cytoplasmic calcium ions (Ca2*,) and hydrogen ions (pHi) as second messengers in the response of osteoblasts to PGE_, stimulation. To do this, we loaded mouse ostoblastic cells (MC3R3-EI) with aequorin (A Ca'-§ sensitive luminescent protein that is insensitive to changes in pHi) and then entrapped the cells in a flow-through cuvctte of a photometer. When we then exposed the ceils to 10 I-tm prostaglandin E2, we observed a rapid increase in Ca"-+ followed by a plateau level above basal. This plateau was maintained as long as PGE2 was present. These changes in Ca2§ evoked by PGE_, were not altered by amiloride, an inhibitor of the N a + / H + exchanger, suggesting that PGE2 does not change the pHi in the cells by altering the activity of the N a + / H + antiporter. The pH sensitive fluorescent probe BCECF also indicated no change in pHi in the presence of PGE2, independently confirming this fir~ding. These results suggest that prostaglandin E2 hzcreases C a 2*~ bat does not change pHi in activathtg osteoblastic cells.
Quantifying malocclusion: A comparison of two malocclusion indices. J. Drew, Son Francisco: "'University of the Pacific, School of Dentisto,, 1992 The purpose of this study is to evaluate two malocclusion indices, the handicapping labiolingual deviation index (HLD)
American Journal of Orthodontics and Dentofacial Orthopedics April 1993
and the modified ocelusal feature index (MOI), for reliability and correlation with a subjective evaluation of malocclusion severity by experts (orthodontic faculty). Pretreatment models and photographs of 30 cases, representing a wide spectrum of malocclusion severity, were evaluated by five orthodontic residents using each index. These same cases were evaluated subjectively, mild, moderate, or severe, by five experts (orthodontic faculty members). Interexaminer and intraexaminer reliability was calculated as was correlation between the index values and subjective values. The interexaminerreliability values were high. The experts value was 0.92. The residents HLD value was 0.94 and MOI value was 0.93. The correlation for intraexaminer reliability was also high at 0.92 (HLD) and 0.99 (MOI). The correlation values were 0.82 (HLD versus experts), 0.71 (MOI versus experts) and 0.68 (HLD versus MOI). htterexamhzer reliability values suggest that each hzdex can be used consistently. The two indices correlate modestly with each other. The HLD had a higher correlation than the MOI with the subjective evahtation by orthodontic facttlty experts.
Radiographic evaluation of TMJ pathology: Comparative study: tomography and panography..1. Irish and D. Hatcher, San Francisco: University of the Pacific, School of Dentistry, 1992
The objective of this study was to assess the ability of the panelipse to discern the information available from corrected tomograms for the evaluation of the temporomandibular joint. Key parameters examined include bony changes of the condyle and fossa, condyle position in the fossa, and condylar form. Records from 50 TMJ patients taken from the Center for Facial Pain, at the University of California, San Francisco, which included both corrected tomograms and panelipse x-ray films of each subject were evaluated. A method of quantitating the shape of the condyles, joint spaces, ramus lengths, and range of maximum opening were developed. Degenerative changes of the condyle and fossa were ranked by three examiners for the presence and severity of sclerosis, flattening, erosions, osteophytes, and subcondylar bone cysts. The examiners included an expert radiologist, an orthodontist who limits his practice to TMJ patients and a second-year orthodontic resident. Findings taken from each technique were compared with the alternate technique using correlation statistics. Examiner reliability was also evaluated. The following conclusions were drawn: 1. Weak correlations exist comparhlg degenerative bony change categories ushtg the two techniques. The recommendation that panoramic x-ray films are acceptable alternatives to corrected tomograms for evaluation of degenerative changes appears haphazard. Information gathered from corrected tomograms does not appear to be collaborated in the panelipse. 2. Condylar shape measttrements gathered front panoramic x-ray fihns in the ntethod used fit this study do not correlate well with the same findings determined front corrected tomograms. Use of these measurements appears to be without practical advantage.