Residents' journal review

Abstract

Long-term changes in untreated dental archesTsiopas N, Nilner M, Bondemark L, Bjerklin K. A 40 years follow-up of dental arch dimensions and incisor irregularity in adults. Eur J Orthod 2011 Oct 19 [Epub ahead of print]Studies describing 40 years of changes in dental arch dimensions and irregularity are rare. Researchers at Malmo University in Sweden followed 35 patients for an average of 38.4 years. The inclusion criteria were no missing teeth, no history of orthodontic or prosthodontic treatment, and at least 20 years of age at the initial records. They were followed up at 10-year and 30-year time points. The results describe 18 patients included in this study. Mandibular incisor crowding increased, with Little’s irregularity index showing a 1.0-mm average change. No changes were observed in the maxilla. Intercanine distances decreased by 1.1 mm in the mandible and by 0.8 mm in the maxilla. Intermolar widths increased by 0.7 mm in the mandible and remained unchanged in the maxilla. Arch lengths decreased in both the mandible and the maxilla, with an average of 0.7 mm mainly at the first follow-up time point. Arch depths decreased in both the mandible and the maxilla, with similar changes for the molars and the canines. The authors believed that this represented a gradual mesial migration of the dentition. No statistically significant changes were found in overjet, overbite, and frequency of Class I occlusion, Class II occlusion, crossbite, open bite, and deepbite. This study confirms the finding of previous studies (Bishara, 1996; Bishara, 1997; Tibana, 2004). The authors concluded that the dentoalveolar process is dynamic and will continue to experience changes throughout an adult’s lifetime. Both patients and orthodontists should be aware of and expect dentoalveolar changes throughout life.Reviewed by Michael C. MeruEffect of intercuspidation on Class II dental correctionThurman MM, King GJ, Ramsay DS, Wheeler TT, Phillips C. The effect of an anterior biteplate on dental and skeletal Class II correction using headgears: a cephalometric study. Orthod Craniofac Res 2011;14:213-21Class II malocclusions include many combinations of dental, skeletal, and esthetic problems that usually do not self-correct. Recent studies have suggested that dental intercuspidation might contribute to the maintenance of a Class II malocclusion despite the greater amount of mandibular growth relative to the maxilla during adolescence. These authors hypothesized that separating the dentition during Class II treatment will enhance the correction of the dental Class II relationship. They compared the cephalometric treatment outcomes between 2 groups: Class II subjects treated with headgear alone, and Class II subjects treated with headgear and biteplane to disclude the posterior teeth. Group 1 (University of Florida) included 81 subjects with a minimum of a bilateral end-to-end Class II molar relationship. Treatment consisted of a biteplane worn full time and headgear (16 ounces) worn 14 hours a day until a Class I molar relationship was achieved, up to 24 months. Group 2 (University of North Carolina) included 50 subjects with overjet of 7 mm or greater, treated with a combination headgear at night (8-10 oz) for 15 months. The authors’ main finding was that the biteplane provided no additional benefit to headgear treatment for Class II growth modification. The biteplane’s occlusal separation did not permit greater mandibular growth or greater forward translation of the mandibular dentition. The headgear-biteplane group did show a significantly greater effect on overbite reduction than did the headgear group, confirming that biteplanes are effective for the correction of deep overbites. The analytic challenges of comparing 2 cohorts from 2 separate randomized clinical trials are discussed.Reviewed by Laura HarshbargerUse of pharmacotherapy to influence condylar resorption: a review of the literatureGunson MJ, Arnett GW, Milam SB. Pathophysiology and pharmacologic control of osseous mandibular condylar resorption. J Oral Maxillofac Surg 2011 Oct 17 [Epub ahead of print]The purpose of this article was to perform a nonsystematic review of the current literature on condylar resorption and the use of pharmacotherapy to control arthritic erosions and resorption. Osseous mandibular condylar resorption can be attributed to numerous factors, including inflammatory arthritis, temporomandibular joint compression, trauma, and hormone imbalances, among others. Although each of these causes is initiated differently, the pathophysiologic pathway for articular bone loss is similar. Based on the current literature, the authors concluded that common events at the cellular level and responsible for articular resorption include activation of osteoblasts by cytokines, free radicals, hormone imbalances, and phospholipid catabolites that release enzymes from the osteoclasts. It is believed that these processes and molecules are responsible for the breakdown of hydroxyapatite and collagen. Previous studies have shown that antioxidants, tetracyclines, omega-3 fatty acids, nonsteroidal anti-inflammatory drugs, and inflammatory cytokine inhibitors have been successful in preventing and controlling articular bone loss. The authors indicated that, by understanding the pathways that lead to condylar resorption and each patient’s susceptibilities, targeted pharmacology might be able to interfere with and prevent further condylar resorption. This would help the surgeon in restoring facial esthetics, airway patency, and occlusal harmony. Further research, in the form of basic clinical investigations and randomized clinical trials, is necessary to determine the effects, indications, and posology of pharmacologic prevention of condylar resorption.Reviewed by George AbichakerPerception of orthodontic bracket prescriptionMoesi B, Dyer F, Benson PE. Roth versus MBT: does bracket prescription have an effect on the subjective outcome of pre-adjusted edgewise treatment? Eur J Orthod 2011 Nov 2 [Epub ahead of print]Since the introduction of the straight wire appliance in the 1970s, there have been many suggested modifications to the tip and torque values used in preadjusted edgewise appliances. A retrospective study was conducted in the orthodontics department of the Charles Clifford Dental Hospital in the United Kingdom to determine whether the bracket prescription has an effect on the subjective outcome of preadjusted edgewise treatment as judged by professionals. Forty sets of posttreatment models from patients treated with preadjusted edgewise appliances (20 Roth, 20 MBT) were selected. The models were shown in random order to 9 experienced orthodontic clinicians, who were asked to assess the quality of the outcome using a prepiloted questionnaire. Differences in esthetic outcomes were examined with a total incisor and canine esthetic torque and tip score. The responses to 6 questions were given a score (0-4) regarding the torque of the maxillary and mandibular incisors, the torque of the maxillary canines, and the tip of the maxillary canines. There were statistically significant differences between the subjective assessments of the 9 judges (P <0.001), but there were no statistically significant differences between the 2 bracket prescriptions (P = 0.900). The best agreement between a clinician’s judgment of the prescription used and the actual prescription was fair (kappa, 0.25; CI, 0.05-0.55). The ability to determine which bracket prescription was used was no better than chance for most clinicians. Bracket prescription had no effect on the subjective esthetic judgment of the outcomes.Reviewed by John JeromeComposite removal and repeated etching during bracket rebondingRüger D, Harzer W, Krisjane Z, Tausche E. Shear bond strength after multiple bracket bonding with or without repeated etching. Eur J Orthod 2001;33:521-7Accidental debonding of brackets is a common problem in orthodontics; hence, researchers try to establish the optimum method for rebonding brackets. Bond strength is considered clinically deficient below 8 MPa and has an increased risk for enamel damage above 13 MPa. In this study, 120 brackets were bonded to extracted premolars. The sample was divided into 3 groups (n = 40), and each bracket was debonded and rebonded 3 times with 3 methods. In group 1, all remaining composite was removed, and the surface was etched and bonded. In group 2, all composite was removed, and the surface was bonded without etching. In group 3, the remaining composite was reduced to a thin but extensive layer, and the surface was rebonded without etching. The techniques used in groups 1 and 3 achieved clinically acceptable bond strengths above 8 MPa, whereas the bond strengths in group 2 fell below this level. Only the bond strengths in group 1 surpassed 13 MPa, and a corresponding increase of enamel tear-outs was seen compared with the other 2 groups. The technique applied in group 3 achieved clinically acceptable bond strengths, maximizing enamel protection. However, it is only appropriate if an extensive layer of composite remains on the tooth surface. The group 1 technique was acceptable but represents increased risk to enamel. The group 2 technique was not clinically acceptable and not recommended.Reviewed by Garrett FongGene therapy and accelerated tooth movementIglesias-Linares A, Moreno-Fernandez AM, Yañes-Vico R, Mendoza-Mendoza A, Gonzalez-Moles M, Solano-Reina E. The use of gene therapy vs corticotomy surgery in accelerating tooth movement. Orthod Craniofac Res 2011;14:138-48It is accepted that corticotomy as an adjunctive treatment to orthodontics induces the so-called regional acceleratory phenomenon and decreases orthodontic treatment time by accelerating tooth movement. Studies have linked the resulting accelerated tooth movement to an increase in osteoclastic activity induced by higher levels of receptor activator of nuclear factor kappa-B ligand (RANKL). The purpose of this study was to compare bone resorption and accelerated tooth movement induction via corticotomy surgery with RANKL gene transfer. For the in-vitro portion, the RANKL expression vector (pcDNA-mRANKL) was transfected into NIH3T3 cells, and protein products were analyzed by PCR, Western blot, and a functional ex-vivo mineral resorption assay. The subsequent in-vivo portion involved a 32-day split-mouth rat study that compared gene therapy with the corticotomy by quantification of RANKL immunofluorescence, fluorescence-based tartrate-resistant acid phosphatase+ (TRAP+) osteoclast counts, and histologic examinations. The investigators observed a 46% (P <0.05) increase in RANKL production and 37.9% (P <0.05) higher bone resorption rates in the transfected samples compared with the controls. The animal study provided similar results, with higher TRAP+ osteoclast counts, a prolonged increased level of RANKL production, and more tooth movement in the transfected group than in both the control and the corticotomy groups. The authors concluded that gene therapy is a more effective way to increase tooth movement compared with surgical corticotomy. Gene therapy could be a viable alternative to corticotomy-assisted orthodontics—the treatment could shorten time and accelerate tooth movement. Further research is needed to evaluate systemic toxicity and possible secondary effects of gene therapy.Reviewed by Stefan Alexandroni Long-term changes in untreated dental archesTsiopas N, Nilner M, Bondemark L, Bjerklin K. A 40 years follow-up of dental arch dimensions and incisor irregularity in adults. Eur J Orthod 2011 Oct 19 [Epub ahead of print]Studies describing 40 years of changes in dental arch dimensions and irregularity are rare. Researchers at Malmo University in Sweden followed 35 patients for an average of 38.4 years. The inclusion criteria were no missing teeth, no history of orthodontic or prosthodontic treatment, and at least 20 years of age at the initial records. They were followed up at 10-year and 30-year time points. The results describe 18 patients included in this study. Mandibular incisor crowding increased, with Little’s irregularity index showing a 1.0-mm average change. No changes were observed in the maxilla. Intercanine distances decreased by 1.1 mm in the mandible and by 0.8 mm in the maxilla. Intermolar widths increased by 0.7 mm in the mandible and remained unchanged in the maxilla. Arch lengths decreased in both the mandible and the maxilla, with an average of 0.7 mm mainly at the first follow-up time point. Arch depths decreased in both the mandible and the maxilla, with similar changes for the molars and the canines. The authors believed that this represented a gradual mesial migration of the dentition. No statistically significant changes were found in overjet, overbite, and frequency of Class I occlusion, Class II occlusion, crossbite, open bite, and deepbite. This study confirms the finding of previous studies (Bishara, 1996; Bishara, 1997; Tibana, 2004). The authors concluded that the dentoalveolar process is dynamic and will continue to experience changes throughout an adult’s lifetime. Both patients and orthodontists should be aware of and expect dentoalveolar changes throughout life.Reviewed by Michael C. Meru Tsiopas N, Nilner M, Bondemark L, Bjerklin K. A 40 years follow-up of dental arch dimensions and incisor irregularity in adults. Eur J Orthod 2011 Oct 19 [Epub ahead of print]Studies describing 40 years of changes in dental arch dimensions and irregularity are rare. Researchers at Malmo University in Sweden followed 35 patients for an average of 38.4 years. The inclusion criteria were no missing teeth, no history of orthodontic or prosthodontic treatment, and at least 20 years of age at the initial records. They were followed up at 10-year and 30-year time points. The results describe 18 patients included in this study. Mandibular incisor crowding increased, with Little’s irregularity index showing a 1.0-mm average change. No changes were observed in the maxilla. Intercanine distances decreased by 1.1 mm in the mandible and by 0.8 mm in the maxilla. Intermolar widths increased by 0.7 mm in the mandible and remained unchanged in the maxilla. Arch lengths decreased in both the mandible and the maxilla, with an average of 0.7 mm mainly at the first follow-up time point. Arch depths decreased in both the mandible and the maxilla, with similar changes for the molars and the canines. The authors believed that this represented a gradual mesial migration of the dentition. No statistically significant changes were found in overjet, overbite, and frequency of Class I occlusion, Class II occlusion, crossbite, open bite, and deepbite. This study confirms the finding of previous studies (Bishara, 1996; Bishara, 1997; Tibana, 2004). The authors concluded that the dentoalveolar process is dynamic and will continue to experience changes throughout an adult’s lifetime. Both patients and orthodontists should be aware of and expect dentoalveolar changes throughout life.Reviewed by Michael C. Meru Studies describing 40 years of changes in dental arch dimensions and irregularity are rare. Researchers at Malmo University in Sweden followed 35 patients for an average of 38.4 years. The inclusion criteria were no missing teeth, no history of orthodontic or prosthodontic treatment, and at least 20 years of age at the initial records. They were followed up at 10-year and 30-year time points. The results describe 18 patients included in this study. Mandibular incisor crowding increased, with Little’s irregularity index showing a 1.0-mm average change. No changes were observed in the maxilla. Intercanine distances decreased by 1.1 mm in the mandible and by 0.8 mm in the maxilla. Intermolar widths increased by 0.7 mm in the mandible and remained unchanged in the maxilla. Arch lengths decreased in both the mandible and the maxilla, with an average of 0.7 mm mainly at the first follow-up time point. Arch depths decreased in both the mandible and the maxilla, with similar changes for the molars and the canines. The authors believed that this represented a gradual mesial migration of the dentition. No statistically significant changes were found in overjet, overbite, and frequency of Class I occlusion, Class II occlusion, crossbite, open bite, and deepbite. This study confirms the finding of previous studies (Bishara, 1996; Bishara, 1997; Tibana, 2004). The authors concluded that the dentoalveolar process is dynamic and will continue to experience changes throughout an adult’s lifetime. Both patients and orthodontists should be aware of and expect dentoalveolar changes throughout life. Reviewed by Michael C. Meru Effect of intercuspidation on Class II dental correctionThurman MM, King GJ, Ramsay DS, Wheeler TT, Phillips C. The effect of an anterior biteplate on dental and skeletal Class II correction using headgears: a cephalometric study. Orthod Craniofac Res 2011;14:213-21Class II malocclusions include many combinations of dental, skeletal, and esthetic problems that usually do not self-correct. Recent studies have suggested that dental intercuspidation might contribute to the maintenance of a Class II malocclusion despite the greater amount of mandibular growth relative to the maxilla during adolescence. These authors hypothesized that separating the dentition during Class II treatment will enhance the correction of the dental Class II relationship. They compared the cephalometric treatment outcomes between 2 groups: Class II subjects treated with headgear alone, and Class II subjects treated with headgear and biteplane to disclude the posterior teeth. Group 1 (University of Florida) included 81 subjects with a minimum of a bilateral end-to-end Class II molar relationship. Treatment consisted of a biteplane worn full time and headgear (16 ounces) worn 14 hours a day until a Class I molar relationship was achieved, up to 24 months. Group 2 (University of North Carolina) included 50 subjects with overjet of 7 mm or greater, treated with a combination headgear at night (8-10 oz) for 15 months. The authors’ main finding was that the biteplane provided no additional benefit to headgear treatment for Class II growth modification. The biteplane’s occlusal separation did not permit greater mandibular growth or greater forward translation of the mandibular dentition. The headgear-biteplane group did show a significantly greater effect on overbite reduction than did the headgear group, confirming that biteplanes are effective for the correction of deep overbites. The analytic challenges of comparing 2 cohorts from 2 separate randomized clinical trials are discussed.Reviewed by Laura Harshbarger Thurman MM, King GJ, Ramsay DS, Wheeler TT, Phillips C. The effect of an anterior biteplate on dental and skeletal Class II correction using headgears: a cephalometric study. Orthod Craniofac Res 2011;14:213-21Class II malocclusions include many combinations of dental, skeletal, and esthetic problems that usually do not self-correct. Recent studies have suggested that dental intercuspidation might contribute to the maintenance of a Class II malocclusion despite the greater amount of mandibular growth relative to the maxilla during adolescence. These authors hypothesized that separating the dentition during Class II treatment will enhance the correction of the dental Class II relationship. They compared the cephalometric treatment outcomes between 2 groups: Class II subjects treated with headgear alone, and Class II subjects treated with headgear and biteplane to disclude the posterior teeth. Group 1 (University of Florida) included 81 subjects with a minimum of a bilateral end-to-end Class II molar relationship. Treatment consisted of a biteplane worn full time and headgear (16 ounces) worn 14 hours a day until a Class I molar relationship was achieved, up to 24 months. Group 2 (University of North Carolina) included 50 subjects with overjet of 7 mm or greater, treated with a combination headgear at night (8-10 oz) for 15 months. The authors’ main finding was that the biteplane provided no additional benefit to headgear treatment for Class II growth modification. The biteplane’s occlusal separation did not permit greater mandibular growth or greater forward translation of the mandibular dentition. The headgear-biteplane group did show a significantly greater effect on overbite reduction than did the headgear group, confirming that biteplanes are effective for the correction of deep overbites. The analytic challenges of comparing 2 cohorts from 2 separate randomized clinical trials are discussed.Reviewed by Laura Harshbarger Class II malocclusions include many combinations of dental, skeletal, and esthetic problems that usually do not self-correct. Recent studies have suggested that dental intercuspidation might contribute to the maintenance of a Class II malocclusion despite the greater amount of mandibular growth relative to the maxilla during adolescence. These authors hypothesized that separating the dentition during Class II treatment will enhance the correction of the dental Class II relationship. They compared the cephalometric treatment outcomes between 2 groups: Class II subjects treated with headgear alone, and Class II subjects treated with headgear and biteplane to disclude the posterior teeth. Group 1 (University of Florida) included 81 subjects with a minimum of a bilateral end-to-end Class II molar relationship. Treatment consisted of a biteplane worn full time and headgear (16 ounces) worn 14 hours a day until a Class I molar relationship was achieved, up to 24 months. Group 2 (University of North Carolina) included 50 subjects with overjet of 7 mm or greater, treated with a combination headgear at night (8-10 oz) for 15 months. The authors’ main finding was that the biteplane provided no additional benefit to headgear treatment for Class II growth modification. The biteplane’s occlusal separation did not permit greater mandibular growth or greater forward translation of the mandibular dentition. The headgear-biteplane group did show a significantly greater effect on overbite reduction than did the headgear group, confirming that biteplanes are effective for the correction of deep overbites. The analytic challenges of comparing 2 cohorts from 2 separate randomized clinical trials are discussed. Reviewed by Laura Harshbarger Use of pharmacotherapy to influence condylar resorption: a review of the literatureGunson MJ, Arnett GW, Milam SB. Pathophysiology and pharmacologic control of osseous mandibular condylar resorption. J Oral Maxillofac Surg 2011 Oct 17 [Epub ahead of print]The purpose of this article was to perform a nonsystematic review of the current literature on condylar resorption and the use of pharmacotherapy to control arthritic erosions and resorption. Osseous mandibular condylar resorption can be attributed to numerous factors, including inflammatory arthritis, temporomandibular joint compression, trauma, and hormone imbalances, among others. Although each of these causes is initiated differently, the pathophysiologic pathway for articular bone loss is similar. Based on the current literature, the authors concluded that common events at the cellular level and responsible for articular resorption include activation of osteoblasts by cytokines, free radicals, hormone imbalances, and phospholipid catabolites that release enzymes from the osteoclasts. It is believed that these processes and molecules are responsible for the breakdown of hydroxyapatite and collagen. Previous studies have shown that antioxidants, tetracyclines, omega-3 fatty acids, nonsteroidal anti-inflammatory drugs, and inflammatory cytokine inhibitors have been successful in preventing and controlling articular bone loss. The authors indicated that, by understanding the pathways that lead to condylar resorption and each patient’s susceptibilities, targeted pharmacology might be able to interfere with and prevent further condylar resorption. This would help the surgeon in restoring facial esthetics, airway patency, and occlusal harmony. Further research, in the form of basic clinical investigations and randomized clinical trials, is necessary to determine the effects, indications, and posology of pharmacologic prevention of condylar resorption.Reviewed by George Abichaker Gunson MJ, Arnett GW, Milam SB. Pathophysiology and pharmacologic control of osseous mandibular condylar resorption. J Oral Maxillofac Surg 2011 Oct 17 [Epub ahead of print]The purpose of this article was to perform a nonsystematic review of the current literature on condylar resorption and the use of pharmacotherapy to control arthritic erosions and resorption. Osseous mandibular condylar resorption can be attributed to numerous factors, including inflammatory arthritis, temporomandibular joint compression, trauma, and hormone imbalances, among others. Although each of these causes is initiated differently, the pathophysiologic pathway for articular bone loss is similar. Based on the current literature, the authors concluded that common events at the cellular level and responsible for articular resorption include activation of osteoblasts by cytokines, free radicals, hormone imbalances, and phospholipid catabolites that release enzymes from the osteoclasts. It is believed that these processes and molecules are responsible for the breakdown of hydroxyapatite and collagen. Previous studies have shown that antioxidants, tetracyclines, omega-3 fatty acids, nonsteroidal anti-inflammatory drugs, and inflammatory cytokine inhibitors have been successful in preventing and controlling articular bone loss. The authors indicated that, by understanding the pathways that lead to condylar resorption and each patient’s susceptibilities, targeted pharmacology might be able to interfere with and prevent further condylar resorption. This would help the surgeon in restoring facial esthetics, airway patency, and occlusal harmony. Further research, in the form of basic clinical investigations and randomized clinical trials, is necessary to determine the effects, indications, and posology of pharmacologic prevention of condylar resorption.Reviewed by George Abichaker The purpose of this article was to perform a nonsystematic review of the current literature on condylar resorption and the use of pharmacotherapy to control arthritic erosions and resorption. Osseous mandibular condylar resorption can be attributed to numerous factors, including inflammatory arthritis, temporomandibular joint compression, trauma, and hormone imbalances, among others. Although each of these causes is initiated differently, the pathophysiologic pathway for articular bone loss is similar. Based on the current literature, the authors concluded that common events at the cellular level and responsible for articular resorption include activation of osteoblasts by cytokines, free radicals, hormone imbalances, and phospholipid catabolites that release enzymes from the osteoclasts. It is believed that these processes and molecules are responsible for the breakdown of hydroxyapatite and collagen. Previous studies have shown that antioxidants, tetracyclines, omega-3 fatty acids, nonsteroidal anti-inflammatory drugs, and inflammatory cytokine inhibitors have been successful in preventing and controlling articular bone loss. The authors indicated that, by understanding the pathways that lead to condylar resorption and each patient’s susceptibilities, targeted pharmacology might be able to interfere with and prevent further condylar resorption. This would help the surgeon in restoring facial esthetics, airway patency, and occlusal harmony. Further research, in the form of basic clinical investigations and randomized clinical trials, is necessary to determine the effects, indications, and posology of pharmacologic prevention of condylar resorption. Reviewed by George Abichaker Perception of orthodontic bracket prescriptionMoesi B, Dyer F, Benson PE. Roth versus MBT: does bracket prescription have an effect on the subjective outcome of pre-adjusted edgewise treatment? Eur J Orthod 2011 Nov 2 [Epub ahead of print]Since the introduction of the straight wire appliance in the 1970s, there have been many suggested modifications to the tip and torque values used in preadjusted edgewise appliances. A retrospective study was conducted in the orthodontics department of the Charles Clifford Dental Hospital in the United Kingdom to determine whether the bracket prescription has an effect on the subjective outcome of preadjusted edgewise treatment as judged by professionals. Forty sets of posttreatment models from patients treated with preadjusted edgewise appliances (20 Roth, 20 MBT) were selected. The models were shown in random order to 9 experienced orthodontic clinicians, who were asked to assess the quality of the outcome using a prepiloted questionnaire. Differences in esthetic outcomes were examined with a total incisor and canine esthetic torque and tip score. The responses to 6 questions were given a score (0-4) regarding the torque of the maxillary and mandibular incisors, the torque of the maxillary canines, and the tip of the maxillary canines. There were statistically significant differences between the subjective assessments of the 9 judges (P <0.001), but there were no statistically significant differences between the 2 bracket prescriptions (P = 0.900). The best agreement between a clinician’s judgment of the prescription used and the actual prescription was fair (kappa, 0.25; CI, 0.05-0.55). The ability to determine which bracket prescription was used was no better than chance for most clinicians. Bracket prescription had no effect on the subjective esthetic judgment of the outcomes.Reviewed by John Jerome Moesi B, Dyer F, Benson PE. Roth versus MBT: does bracket prescription have an effect on the subjective outcome of pre-adjusted edgewise treatment? Eur J Orthod 2011 Nov 2 [Epub ahead of print]Since the introduction of the straight wire appliance in the 1970s, there have been many suggested modifications to the tip and torque values used in preadjusted edgewise appliances. A retrospective study was conducted in the orthodontics department of the Charles Clifford Dental Hospital in the United Kingdom to determine whether the bracket prescription has an effect on the subjective outcome of preadjusted edgewise treatment as judged by professionals. Forty sets of posttreatment models from patients treated with preadjusted edgewise appliances (20 Roth, 20 MBT) were selected. The models were shown in random order to 9 experienced orthodontic clinicians, who were asked to assess the quality of the outcome using a prepiloted questionnaire. Differences in esthetic outcomes were examined with a total incisor and canine esthetic torque and tip score. The responses to 6 questions were given a score (0-4) regarding the torque of the maxillary and mandibular incisors, the torque of the maxillary canines, and the tip of the maxillary canines. There were statistically significant differences between the subjective assessments of the 9 judges (P <0.001), but there were no statistically significant differences between the 2 bracket prescriptions (P = 0.900). The best agreement between a clinician’s judgment of the prescription used and the actual prescription was fair (kappa, 0.25; CI, 0.05-0.55). The ability to determine which bracket prescription was used was no better than chance for most clinicians. Bracket prescription had no effect on the subjective esthetic judgment of the outcomes.Reviewed by John Jerome Since the introduction of the straight wire appliance in the 1970s, there have been many suggested modifications to the tip and torque values used in preadjusted edgewise appliances. A retrospective study was conducted in the orthodontics department of the Charles Clifford Dental Hospital in the United Kingdom to determine whether the bracket prescription has an effect on the subjective outcome of preadjusted edgewise treatment as judged by professionals. Forty sets of posttreatment models from patients treated with preadjusted edgewise appliances (20 Roth, 20 MBT) were selected. The models were shown in random order to 9 experienced orthodontic clinicians, who were asked to assess the quality of the outcome using a prepiloted questionnaire. Differences in esthetic outcomes were examined with a total incisor and canine esthetic torque and tip score. The responses to 6 questions were given a score (0-4) regarding the torque of the maxillary and mandibular incisors, the torque of the maxillary canines, and the tip of the maxillary canines. There were statistically significant differences between the subjective assessments of the 9 judges (P <0.001), but there were no statistically significant differences between the 2 bracket prescriptions (P = 0.900). The best agreement between a clinician’s judgment of the prescription used and the actual prescription was fair (kappa, 0.25; CI, 0.05-0.55). The ability to determine which bracket prescription was used was no better than chance for most clinicians. Bracket prescription had no effect on the subjective esthetic judgment of the outcomes. Reviewed by John Jerome Composite removal and repeated etching during bracket rebondingRüger D, Harzer W, Krisjane Z, Tausche E. Shear bond strength after multiple bracket bonding with or without repeated etching. Eur J Orthod 2001;33:521-7Accidental debonding of brackets is a common problem in orthodontics; hence, researchers try to establish the optimum method for rebonding brackets. Bond strength is considered clinically deficient below 8 MPa and has an increased risk for enamel damage above 13 MPa. In this study, 120 brackets were bonded to extracted premolars. The sample was divided into 3 groups (n = 40), and each bracket was debonded and rebonded 3 times with 3 methods. In group 1, all remaining composite was removed, and the surface was etched and bonded. In group 2, all composite was removed, and the surface was bonded without etching. In group 3, the remaining composite was reduced to a thin but extensive layer, and the surface was rebonded without etching. The techniques used in groups 1 and 3 achieved clinically acceptable bond strengths above 8 MPa, whereas the bond strengths in group 2 fell below this level. Only the bond strengths in group 1 surpassed 13 MPa, and a corresponding increase of enamel tear-outs was seen compared with the other 2 groups. The technique applied in group 3 achieved clinically acceptable bond strengths, maximizing enamel protection. However, it is only appropriate if an extensive layer of composite remains on the tooth surface. The group 1 technique was acceptable but represents increased risk to enamel. The group 2 technique was not clinically acceptable and not recommended.Reviewed by Garrett Fong Rüger D, Harzer W, Krisjane Z, Tausche E. Shear bond strength after multiple bracket bonding with or without repeated etching. Eur J Orthod 2001;33:521-7Accidental debonding of brackets is a common problem in orthodontics; hence, researchers try to establish the optimum method for rebonding brackets. Bond strength is considered clinically deficient below 8 MPa and has an increased risk for enamel damage above 13 MPa. In this study, 120 brackets were bonded to extracted premolars. The sample was divided into 3 groups (n = 40), and each bracket was debonded and rebonded 3 times with 3 methods. In group 1, all remaining composite was removed, and the surface was etched and bonded. In group 2, all composite was removed, and the surface was bonded without etching. In group 3, the remaining composite was reduced to a thin but extensive layer, and the surface was rebonded without etching. The techniques used in groups 1 and 3 achieved clinically acceptable bond strengths above 8 MPa, whereas the bond strengths in group 2 fell below this level. Only the bond strengths in group 1 surpassed 13 MPa, and a corresponding increase of enamel tear-outs was seen compared with the other 2 groups. The technique applied in group 3 achieved clinically acceptable bond strengths, maximizing enamel protection. However, it is only appropriate if an extensive layer of composite remains on the tooth surface. The group 1 technique was acceptable but represents increased risk to enamel. The group 2 technique was not clinically acceptable and not recommended.Reviewed by Garrett Fong Accidental debonding of brackets is a common problem in orthodontics; hence, researchers try to establish the optimum method for rebonding brackets. Bond strength is considered clinically deficient below 8 MPa and has an increased risk for enamel damage above 13 MPa. In this study, 120 brackets were bonded to extracted premolars. The sample was divided into 3 groups (n = 40), and each bracket was debonded and rebonded 3 times with 3 methods. In group 1, all remaining composite was removed, and the surface was etched and bonded. In group 2, all composite was removed, and the surface was bonded without etching. In group 3, the remaining composite was reduced to a thin but extensive layer, and the surface was rebonded without etching. The techniques used in groups 1 and 3 achieved clinically acceptable bond strengths above 8 MPa, whereas the bond strengths in group 2 fell below this level. Only the bond strengths in group 1 surpassed 13 MPa, and a corresponding increase of enamel tear-outs was seen compared with the other 2 groups. The technique applied in group 3 achieved clinically acceptable bond strengths, maximizing enamel protection. However, it is only appropriate if an extensive layer of composite remains on the tooth surface. The group 1 technique was acceptable but represents increased risk to enamel. The group 2 technique was not clinically acceptable and not recommended. Reviewed by Garrett Fong Gene therapy and accelerated tooth movementIglesias-Linares A, Moreno-Fernandez AM, Yañes-Vico R, Mendoza-Mendoza A, Gonzalez-Moles M, Solano-Reina E. The use of gene therapy vs corticotomy surgery in accelerating tooth movement. Orthod Craniofac Res 2011;14:138-48It is accepted that corticotomy as an adjunctive treatment to orthodontics induces the so-called regional acceleratory phenomenon and decreases orthodontic treatment time by accelerating tooth movement. Studies have linked the resulting accelerated tooth movement to an increase in osteoclastic activity induced by higher levels of receptor activator of nuclear factor kappa-B ligand (RANKL). The purpose of this study was to compare bone resorption and accelerated tooth movement induction via corticotomy surgery with RANKL gene transfer. For the in-vitro portion, the RANKL expression vector (pcDNA-mRANKL) was transfected into NIH3T3 cells, and protein products were analyzed by PCR, Western blot, and a functional ex-vivo mineral resorption assay. The subsequent in-vivo portion involved a 32-day split-mouth rat study that compared gene therapy with the corticotomy by quantification of RANKL immunofluorescence, fluorescence-based tartrate-resistant acid phosphatase+ (TRAP+) osteoclast counts, and histologic examinations. The investigators observed a 46% (P <0.05) increase in RANKL production and 37.9% (P <0.05) higher bone resorption rates in the transfected samples compared with the controls. The animal study provided similar results, with higher TRAP+ osteoclast counts, a prolonged increased level of RANKL production, and more tooth movement in the transfected group than in both the control and the corticotomy groups. The authors concluded that gene therapy is a more effective way to increase tooth movement compared with surgical corticotomy. Gene therapy could be a viable alternative to corticotomy-assisted orthodontics—the treatment could shorten time and accelerate tooth movement. Further research is needed to evaluate systemic toxicity and possible secondary effects of gene therapy.Reviewed by Stefan Alexandroni Iglesias-Linares A, Moreno-Fernandez AM, Yañes-Vico R, Mendoza-Mendoza A, Gonzalez-Moles M, Solano-Reina E. The use of gene therapy vs corticotomy surgery in accelerating tooth movement. Orthod Craniofac Res 2011;14:138-48It is accepted that corticotomy as an adjunctive treatment to orthodontics induces the so-called regional acceleratory phenomenon and decreases orthodontic treatment time by accelerating tooth movement. Studies have linked the resulting accelerated tooth movement to an increase in osteoclastic activity induced by higher levels of receptor activator of nuclear factor kappa-B ligand (RANKL). The purpose of this study was to compare bone resorption and accelerated tooth movement induction via corticotomy surgery with RANKL gene transfer. For the in-vitro portion, the RANKL expression vector (pcDNA-mRANKL) was transfected into NIH3T3 cells, and protein products were analyzed by PCR, Western blot, and a functional ex-vivo mineral resorption assay. The subsequent in-vivo portion involved a 32-day split-mouth rat study that compared gene therapy with the corticotomy by quantification of RANKL immunofluorescence, fluorescence-based tartrate-resistant acid phosphatase+ (TRAP+) osteoclast counts, and histologic examinations. The investigators observed a 46% (P <0.05) increase in RANKL production and 37.9% (P <0.05) higher bone resorption rates in the transfected samples compared with the controls. The animal study provided similar results, with higher TRAP+ osteoclast counts, a prolonged increased level of RANKL production, and more tooth movement in the transfected group than in both the control and the corticotomy groups. The authors concluded that gene therapy is a more effective way to increase tooth movement compared with surgical corticotomy. Gene therapy could be a viable alternative to corticotomy-assisted orthodontics—the treatment could shorten time and accelerate tooth movement. Further research is needed to evaluate systemic toxicity and possible secondary effects of gene therapy.Reviewed by Stefan Alexandroni It is accepted that corticotomy as an adjunctive treatment to orthodontics induces the so-called regional acceleratory phenomenon and decreases orthodontic treatment time by accelerating tooth movement. Studies have linked the resulting accelerated tooth movement to an increase in osteoclastic activity induced by higher levels of receptor activator of nuclear factor kappa-B ligand (RANKL). The purpose of this study was to compare bone resorption and accelerated tooth movement induction via corticotomy surgery with RANKL gene transfer. For the in-vitro portion, the RANKL expression vector (pcDNA-mRANKL) was transfected into NIH3T3 cells, and protein products were analyzed by PCR, Western blot, and a functional ex-vivo mineral resorption assay. The subsequent in-vivo portion involved a 32-day split-mouth rat study that compared gene therapy with the corticotomy by quantification of RANKL immunofluorescence, fluorescence-based tartrate-resistant acid phosphatase+ (TRAP+) osteoclast counts, and histologic examinations. The investigators observed a 46% (P <0.05) increase in RANKL production and 37.9% (P <0.05) higher bone resorption rates in the transfected samples compared with the controls. The animal study provided similar results, with higher TRAP+ osteoclast counts, a prolonged increased level of RANKL production, and more tooth movement in the transfected group than in both the control and the corticotomy groups. The authors concluded that gene therapy is a more effective way to increase tooth movement compared with surgical corticotomy. Gene therapy could be a viable alternative to corticotomy-assisted orthodontics—the treatment could shorten time and accelerate tooth movement. Further research is needed to evaluate systemic toxicity and possible secondary effects of gene therapy. Reviewed by Stefan Alexandroni