Residents’ journal review

Abstract

Assessing risk of gingival recession in adultsSarfati A, Bourgeois D, Katsahian S, Mora F, Bouchard P. Risk assessment for buccal gingival recession defects in an adult population. J Periodontol 2010;81:1419-25Gingival recession is common in adults. However, it is not clear how periodontal, systemic, and environmental factors are associated with gingival recession. This cross-sectional study examined some of the risk factors. The data originated in the First National Periodontal and Systemic Examination Survey; 1093 men and 1051 women, aged 35 to 65 years, were selected with a multi-stage stratification method by age, sex, socioeconomic status, and region to represent the total French civilian population. Full-mouth periodontal evaluation, biometric data, body mass index, blood serum glucose concentration, frequency of dental visits, smoking status, and alcohol consumption were all recorded. The extent and the severity of midbuccal recession were the focus of the study and were measured as the number of affected sites and quantified in millimeters. Mesial and distal buccal sites were used for the Miller classifications. Age, sex, alcohol consumption, and diabetic status were set as the categorical variables for the multivariate linear regression models with backward selection. The results demonstrated that 84.6% of the sample had at least 1 recession site. Only 1.8% of the sample had severe recession (≥6 mm). The Miller classes I and II included most of the sample; gingival recession could affect any tooth. Age, sex, plaque index, and tobacco consumption are independent risk factors for the extent and severity of gingival recessions. Furthermore, the number of missing teeth and the gingival bleeding index are related to the severity of gingival defects. Diabetes, increase of body mass index, alcohol intake, and dental visits showed no correlation with gingival recession.Reviewed by YunYan Tracy ShenSystematic review of profile change after maxillofacial surgeryJoss CU, Joss-Vassalli IM, Bergé SJ, Kuijpers-Jagtman AM. Soft tissue profile changes after bilateral sagittal split osteotomy for mandibular setback: a systematic review. J Oral Maxillofac Surg 2010;68:2792-801; e-pub, August 2010The prediction of facial profile changes after maxillofacial surgery is a significant part of treatment planning for surgical orthodontic patients. Since most clinicians use a 2-dimensional approach with lateral cephalograms, the availability of precise research data as a basis for prediction software is critical. This article provides a systematic review of the literature on the soft-tissue changes in patients who underwent bilateral sagittal split osteotomies for mandibular setback. The authors sought to determine the ratio between soft-tissue and hard-tissue movements and illustrate differences in short-term and long-term results. An online search resulted in 766 articles. After assessment and extraction of the articles by 2 observers, 8 articles met the inclusion criteria and were selected. Studies other than human clinical trials, and those with syndromic patients and patients who needed further surgical intervention, or sample sizes less than 10, were excluded. The authors observed that anteroposterior changes in lower lip to mandibular incisor and mentolabial fold to B-point had a 1:1 ratio in both the short and long terms. Soft-tissue pogonion to pogonion exhibited a 1:1 ratio in the short term but was lower in the long term. The response of the upper lip was highly variable when compared with the mandibular incisor, B-point, and pogonion, primarily exhibiting protrusion. Evidence-based conclusions on soft-tissue changes are difficult to draw, and there is a need for well-designed prospective studies with adequate sample sizes and exclusion of additional surgical procedures. Moreover, variability in postsurgical relapse and the presence of bonded brackets are variables that might affect the accuracy of measurements and should be considered in the future.Reviewed by Christine KownatzkiOne-year comparison of 3 retention methodsEdman Tynelius G, Bondemark L, Lilja-Karlander E. Evaluation of orthodontic treatment after 1 year of retention—a randomized controlled trial. Eur J Orthod 2010;32:542-7; e-pub, January 2010The aims of this randomized controlled trial were to evaluate and compare 3 retention methods after 1 year of orthodontic retention. Seventy-five patients were recruited and randomly assigned to 3 groups of 25: a vacuum-formed retainer in the maxilla and bonded canine-to-canine retainer in the mandible, a vacuum-formed retainer in the maxilla combined with stripping of the 10 proximal surfaces of the mandibular anterior teeth, and a prefabricated positioner covering the teeth in the maxilla and the mandible. The inclusion criteria were treatment plan involving extraction of 4 premolars, space deficiencies in both jaws, Class I molar relationship or 3-mm anterior-posterior deviation, permanent dentition, and no prior orthodontic treatment. All subjects underwent fixed straight-wire appliance treatment by 1 orthodontist. Dental casts were obtained at 3 times: before treatment, immediately after treatment, and after 12 months of retention. Six measurements—Little’s irregularity index, intercanine width, intermolar width, arch length, overjet, and overbite—were obtained. The groups were compared by 1-way analysis of variance (ANOVA). The results showed that, on a short-term basis (1 year), all 3 retention strategies had an equal capacity to retain the orthodontic treatment results. Small but significant differences were seen in mandibular intercanine width, mandibular arch length, and overbite groups 1 and 2. The authors asserted that this study was the first randomized controlled trial study to demonstrate that mandibular anterior stripping without additional retention methods was sufficient for successful retention, and that a positioner can be used in the permanent dentition as a successful short-term retention device.Reviewed by Vanessa KuEffect of glucocorticoids on osteoclasts and bone resorptionSøe K, Delaissé JM. Glucocorticoids maintain human osteoclasts in the active mode of their resorption cycle. J Bone Miner Res 2010;25:2184-92Glucocorticoids (GCs) are widely used immune suppressants that can lead to bone loss. Previous studies have shown that high doses of GCs impair the function of osteoblasts, therefore having a negative impact on bone formation. However, the impairment of osteoblasts alone does not explain a rapid increase in fracture risk in the first 3 to 6 months of treatment. This study examined the effect of GCs on osteoclasts (OCs) and bone resorption. Mature human OCs were generated from CD14+ cells in the presence of M-CSF and RANKL and then seeded on bone slices with the addition of 1.6 μM of prednisolone in the experimental group. The results showed that GCs act directly on OCs and change the morphology of resorption lacunae. No difference was found in the total resorbed bone surface, and metabolic activity was either unaffected or negatively affected in the experimental group. With GCs, there was a 30% increase in the number of deeper and elongated trenches, an increase in TRACP (OCs activity marker), a 3-times increase in CTX levels (OC collagenolysis activity marker), and less collagen left over at the bottom of the excavations. Exposure to GCs changes the resorption pattern of OCs from alternating between resorption and migration to continuous erosion of the bone surface. This behavioral change is thought to occur through enhanced collagenolysis, ensuring prolonged contact between OCs and mineral components. The authors concluded that the change in osteoclastic resorption mode from intermittent to continuous might contribute to the early bone fragilization of patients treated with GCs.Reviewed by Ga LeeUpper airway length and sleep apneaSusarla SM, Abramson ZR, Dodson TB, Kaban LB. Cephalometric measurement of upper airway length correlates with the presence and severity of obstructive sleep apnea. J Oral Maxillofac Surg 2010;68:2846-55Obstructive sleep apnea (OSA) is a breathing disorder characterized by recurrent episodic collapses of the upper airway and is associated with increases in resistance to airflow in the pharyngeal airway. Previous studies have established a correlation between upper airway length (UAL), measured on computed tomograms, with the presence and severity of OSA. However, using computed tomography scans to evaluate OSA can be costly, inconvenient, and excessive in radiation exposure. The aims of this study were to measure UAL on lateral cephalograms and to assess its relationship with the presence and severity of OSA. The authors hypothesized that UAL, measured along the long axis of the airway from the posterior palate to the superior hyoid would be longer in patients with OSA. With a case-control study design, 96 adults with OSA and 56 controls with skeletal Class II malocclusion without OSA were enrolled. The respiratory disturbance index (RDI) was used to measure disease severity. Bivariate analysis indicated that OSA subjects were predominately older and male, and had a higher body mass index, longer and narrower airway, longer hyoid-mandible distance, and longer soft palates. UAL was significantly longer in patients with OSA and is a predictor of OSA in both men and women, with UAL of ≥72 mm in men and ≥62 mm in women. UAL strongly correlated with RDI in men and moderately correlated with RDI in women. The results demonstrated high sensitivity and high specificity of UAL for the diagnosis of OSA. The authors recommended that UAL should be included in the routine cephalometric measurements for evaluating and following patients with OSA.Reviewed by Betty ChenExpanding sutures with continuous forcesLiu SS, Kyung HM, Buschang PH. Continuous forces are more effective than intermittent forces in expanding sutures. Eur J Orthod 2010;32:371-80; e-pub, January 2010The authors reported greater sutural separation and bone formation with continuous forces vs intermittent forces in a suture-expansion study involving juvenile male New Zealand white rabbits. A 50-g expansion force was generated by a nickel-titanium open-coil spring placed between 2 titanium miniscrew implants. These implants were located 4 to 5 mm from the midsagittal suture on the dorsum of the cranium. One group (n = 7) had the force applied continuously for 29 consecutive days. The second group (n = 7) had the force applied intermittently (5 days on, 1 day off) for 29 days. Two fluorescent bone labels, oxytetracycline and calcein, were administered to all animals at various times during the study to quantify new bone formation. The continuous group averaged 1.3 mm of sutural separation, and the intermittent group showed 0.8 mm of separation. The 4 one-day breaks in the intermittent group resulted in a 61% sutural opening compared with the continuous group. Since forces were applied for 86% of the time in the intermittent group, the authors calculated a relapse of 25% and cited the recoil of stretched collagen fibers as reasons for relapse. Between days 7 and 17, the intermittent group showed 59% as much mineral apposition and 61% as much bone formation; sutural bone formation was proportional to sutural separation. The authors mentioned other mineralized tissue adaptation studies with long bones that showed greater endocortical and periosteal activity under oscillating loads. However, this study suggests that, for sutural bone growth, continuous forces are more effective.Reviewed by Jared T. LeePulpal vitality of traumatized maxillary incisorsBauss O, Schäfer W, Sadat-Khonsari R, Knösel M. Influence of orthodontic extrusion on pulpal vitality of traumatized maxillary incisors. J Endod 2010;36:203-7; e-pub, December 2009This retrospective study aimed to investigate the effects of orthodontic extrusion on the pulpal vitality of previously traumatized maxillary incisors. Patients were selected at 3 private orthodontic practices. Three groups were compared. Group 1 (n = 77 teeth) underwent orthodontic treatment to extrude a previously traumatized and vital maxillary incisor. Group 2 included orthodontic patients with no trauma history (n = 400), and group 3 had traumatized teeth with no orthodontic treatment (n = 193). Groups 1 and 3 were further subdivided into subgroups: periodontal injuries (subluxation, extrusion, lateral luxation, and intrusive luxation) and hard-tissue lesions (fracture of enamel or enamel and dentin). Pulpal vitality was diagnosed by using crown color, cryogenic spray, and periapical and panoramic radiographs. Differences between the groups were tested with the chi-square test and α = 0.05. Greater losses of vitality were found in the orthodontics and trauma group with periodontal injuries compared with the orthodontic group (P <0.001) and the trauma group (P <0.004). No differences were found between the central and lateral incisors or in hard-tissue lesions with or without orthodontic treatment. The authors concluded that maxillary incisors were in more danger of pulpal necrosis if they had a history of periodontal trauma. They also recommended the use lighter extrusive forces during treatment. The frequency of devitalization was small (9.1%, 0.5%, and 1.6%, respectively, in the 3 groups). Further research with larger groups of patients is needed to increase the statistical power.Reviewed by Brendan Smith Assessing risk of gingival recession in adultsSarfati A, Bourgeois D, Katsahian S, Mora F, Bouchard P. Risk assessment for buccal gingival recession defects in an adult population. J Periodontol 2010;81:1419-25Gingival recession is common in adults. However, it is not clear how periodontal, systemic, and environmental factors are associated with gingival recession. This cross-sectional study examined some of the risk factors. The data originated in the First National Periodontal and Systemic Examination Survey; 1093 men and 1051 women, aged 35 to 65 years, were selected with a multi-stage stratification method by age, sex, socioeconomic status, and region to represent the total French civilian population. Full-mouth periodontal evaluation, biometric data, body mass index, blood serum glucose concentration, frequency of dental visits, smoking status, and alcohol consumption were all recorded. The extent and the severity of midbuccal recession were the focus of the study and were measured as the number of affected sites and quantified in millimeters. Mesial and distal buccal sites were used for the Miller classifications. Age, sex, alcohol consumption, and diabetic status were set as the categorical variables for the multivariate linear regression models with backward selection. The results demonstrated that 84.6% of the sample had at least 1 recession site. Only 1.8% of the sample had severe recession (≥6 mm). The Miller classes I and II included most of the sample; gingival recession could affect any tooth. Age, sex, plaque index, and tobacco consumption are independent risk factors for the extent and severity of gingival recessions. Furthermore, the number of missing teeth and the gingival bleeding index are related to the severity of gingival defects. Diabetes, increase of body mass index, alcohol intake, and dental visits showed no correlation with gingival recession.Reviewed by YunYan Tracy Shen Sarfati A, Bourgeois D, Katsahian S, Mora F, Bouchard P. Risk assessment for buccal gingival recession defects in an adult population. J Periodontol 2010;81:1419-25Gingival recession is common in adults. However, it is not clear how periodontal, systemic, and environmental factors are associated with gingival recession. This cross-sectional study examined some of the risk factors. The data originated in the First National Periodontal and Systemic Examination Survey; 1093 men and 1051 women, aged 35 to 65 years, were selected with a multi-stage stratification method by age, sex, socioeconomic status, and region to represent the total French civilian population. Full-mouth periodontal evaluation, biometric data, body mass index, blood serum glucose concentration, frequency of dental visits, smoking status, and alcohol consumption were all recorded. The extent and the severity of midbuccal recession were the focus of the study and were measured as the number of affected sites and quantified in millimeters. Mesial and distal buccal sites were used for the Miller classifications. Age, sex, alcohol consumption, and diabetic status were set as the categorical variables for the multivariate linear regression models with backward selection. The results demonstrated that 84.6% of the sample had at least 1 recession site. Only 1.8% of the sample had severe recession (≥6 mm). The Miller classes I and II included most of the sample; gingival recession could affect any tooth. Age, sex, plaque index, and tobacco consumption are independent risk factors for the extent and severity of gingival recessions. Furthermore, the number of missing teeth and the gingival bleeding index are related to the severity of gingival defects. Diabetes, increase of body mass index, alcohol intake, and dental visits showed no correlation with gingival recession.Reviewed by YunYan Tracy Shen Gingival recession is common in adults. However, it is not clear how periodontal, systemic, and environmental factors are associated with gingival recession. This cross-sectional study examined some of the risk factors. The data originated in the First National Periodontal and Systemic Examination Survey; 1093 men and 1051 women, aged 35 to 65 years, were selected with a multi-stage stratification method by age, sex, socioeconomic status, and region to represent the total French civilian population. Full-mouth periodontal evaluation, biometric data, body mass index, blood serum glucose concentration, frequency of dental visits, smoking status, and alcohol consumption were all recorded. The extent and the severity of midbuccal recession were the focus of the study and were measured as the number of affected sites and quantified in millimeters. Mesial and distal buccal sites were used for the Miller classifications. Age, sex, alcohol consumption, and diabetic status were set as the categorical variables for the multivariate linear regression models with backward selection. The results demonstrated that 84.6% of the sample had at least 1 recession site. Only 1.8% of the sample had severe recession (≥6 mm). The Miller classes I and II included most of the sample; gingival recession could affect any tooth. Age, sex, plaque index, and tobacco consumption are independent risk factors for the extent and severity of gingival recessions. Furthermore, the number of missing teeth and the gingival bleeding index are related to the severity of gingival defects. Diabetes, increase of body mass index, alcohol intake, and dental visits showed no correlation with gingival recession. Reviewed by YunYan Tracy Shen Systematic review of profile change after maxillofacial surgeryJoss CU, Joss-Vassalli IM, Bergé SJ, Kuijpers-Jagtman AM. Soft tissue profile changes after bilateral sagittal split osteotomy for mandibular setback: a systematic review. J Oral Maxillofac Surg 2010;68:2792-801; e-pub, August 2010The prediction of facial profile changes after maxillofacial surgery is a significant part of treatment planning for surgical orthodontic patients. Since most clinicians use a 2-dimensional approach with lateral cephalograms, the availability of precise research data as a basis for prediction software is critical. This article provides a systematic review of the literature on the soft-tissue changes in patients who underwent bilateral sagittal split osteotomies for mandibular setback. The authors sought to determine the ratio between soft-tissue and hard-tissue movements and illustrate differences in short-term and long-term results. An online search resulted in 766 articles. After assessment and extraction of the articles by 2 observers, 8 articles met the inclusion criteria and were selected. Studies other than human clinical trials, and those with syndromic patients and patients who needed further surgical intervention, or sample sizes less than 10, were excluded. The authors observed that anteroposterior changes in lower lip to mandibular incisor and mentolabial fold to B-point had a 1:1 ratio in both the short and long terms. Soft-tissue pogonion to pogonion exhibited a 1:1 ratio in the short term but was lower in the long term. The response of the upper lip was highly variable when compared with the mandibular incisor, B-point, and pogonion, primarily exhibiting protrusion. Evidence-based conclusions on soft-tissue changes are difficult to draw, and there is a need for well-designed prospective studies with adequate sample sizes and exclusion of additional surgical procedures. Moreover, variability in postsurgical relapse and the presence of bonded brackets are variables that might affect the accuracy of measurements and should be considered in the future.Reviewed by Christine Kownatzki Joss CU, Joss-Vassalli IM, Bergé SJ, Kuijpers-Jagtman AM. Soft tissue profile changes after bilateral sagittal split osteotomy for mandibular setback: a systematic review. J Oral Maxillofac Surg 2010;68:2792-801; e-pub, August 2010The prediction of facial profile changes after maxillofacial surgery is a significant part of treatment planning for surgical orthodontic patients. Since most clinicians use a 2-dimensional approach with lateral cephalograms, the availability of precise research data as a basis for prediction software is critical. This article provides a systematic review of the literature on the soft-tissue changes in patients who underwent bilateral sagittal split osteotomies for mandibular setback. The authors sought to determine the ratio between soft-tissue and hard-tissue movements and illustrate differences in short-term and long-term results. An online search resulted in 766 articles. After assessment and extraction of the articles by 2 observers, 8 articles met the inclusion criteria and were selected. Studies other than human clinical trials, and those with syndromic patients and patients who needed further surgical intervention, or sample sizes less than 10, were excluded. The authors observed that anteroposterior changes in lower lip to mandibular incisor and mentolabial fold to B-point had a 1:1 ratio in both the short and long terms. Soft-tissue pogonion to pogonion exhibited a 1:1 ratio in the short term but was lower in the long term. The response of the upper lip was highly variable when compared with the mandibular incisor, B-point, and pogonion, primarily exhibiting protrusion. Evidence-based conclusions on soft-tissue changes are difficult to draw, and there is a need for well-designed prospective studies with adequate sample sizes and exclusion of additional surgical procedures. Moreover, variability in postsurgical relapse and the presence of bonded brackets are variables that might affect the accuracy of measurements and should be considered in the future.Reviewed by Christine Kownatzki The prediction of facial profile changes after maxillofacial surgery is a significant part of treatment planning for surgical orthodontic patients. Since most clinicians use a 2-dimensional approach with lateral cephalograms, the availability of precise research data as a basis for prediction software is critical. This article provides a systematic review of the literature on the soft-tissue changes in patients who underwent bilateral sagittal split osteotomies for mandibular setback. The authors sought to determine the ratio between soft-tissue and hard-tissue movements and illustrate differences in short-term and long-term results. An online search resulted in 766 articles. After assessment and extraction of the articles by 2 observers, 8 articles met the inclusion criteria and were selected. Studies other than human clinical trials, and those with syndromic patients and patients who needed further surgical intervention, or sample sizes less than 10, were excluded. The authors observed that anteroposterior changes in lower lip to mandibular incisor and mentolabial fold to B-point had a 1:1 ratio in both the short and long terms. Soft-tissue pogonion to pogonion exhibited a 1:1 ratio in the short term but was lower in the long term. The response of the upper lip was highly variable when compared with the mandibular incisor, B-point, and pogonion, primarily exhibiting protrusion. Evidence-based conclusions on soft-tissue changes are difficult to draw, and there is a need for well-designed prospective studies with adequate sample sizes and exclusion of additional surgical procedures. Moreover, variability in postsurgical relapse and the presence of bonded brackets are variables that might affect the accuracy of measurements and should be considered in the future. Reviewed by Christine Kownatzki One-year comparison of 3 retention methodsEdman Tynelius G, Bondemark L, Lilja-Karlander E. Evaluation of orthodontic treatment after 1 year of retention—a randomized controlled trial. Eur J Orthod 2010;32:542-7; e-pub, January 2010The aims of this randomized controlled trial were to evaluate and compare 3 retention methods after 1 year of orthodontic retention. Seventy-five patients were recruited and randomly assigned to 3 groups of 25: a vacuum-formed retainer in the maxilla and bonded canine-to-canine retainer in the mandible, a vacuum-formed retainer in the maxilla combined with stripping of the 10 proximal surfaces of the mandibular anterior teeth, and a prefabricated positioner covering the teeth in the maxilla and the mandible. The inclusion criteria were treatment plan involving extraction of 4 premolars, space deficiencies in both jaws, Class I molar relationship or 3-mm anterior-posterior deviation, permanent dentition, and no prior orthodontic treatment. All subjects underwent fixed straight-wire appliance treatment by 1 orthodontist. Dental casts were obtained at 3 times: before treatment, immediately after treatment, and after 12 months of retention. Six measurements—Little’s irregularity index, intercanine width, intermolar width, arch length, overjet, and overbite—were obtained. The groups were compared by 1-way analysis of variance (ANOVA). The results showed that, on a short-term basis (1 year), all 3 retention strategies had an equal capacity to retain the orthodontic treatment results. Small but significant differences were seen in mandibular intercanine width, mandibular arch length, and overbite groups 1 and 2. The authors asserted that this study was the first randomized controlled trial study to demonstrate that mandibular anterior stripping without additional retention methods was sufficient for successful retention, and that a positioner can be used in the permanent dentition as a successful short-term retention device.Reviewed by Vanessa Ku Edman Tynelius G, Bondemark L, Lilja-Karlander E. Evaluation of orthodontic treatment after 1 year of retention—a randomized controlled trial. Eur J Orthod 2010;32:542-7; e-pub, January 2010The aims of this randomized controlled trial were to evaluate and compare 3 retention methods after 1 year of orthodontic retention. Seventy-five patients were recruited and randomly assigned to 3 groups of 25: a vacuum-formed retainer in the maxilla and bonded canine-to-canine retainer in the mandible, a vacuum-formed retainer in the maxilla combined with stripping of the 10 proximal surfaces of the mandibular anterior teeth, and a prefabricated positioner covering the teeth in the maxilla and the mandible. The inclusion criteria were treatment plan involving extraction of 4 premolars, space deficiencies in both jaws, Class I molar relationship or 3-mm anterior-posterior deviation, permanent dentition, and no prior orthodontic treatment. All subjects underwent fixed straight-wire appliance treatment by 1 orthodontist. Dental casts were obtained at 3 times: before treatment, immediately after treatment, and after 12 months of retention. Six measurements—Little’s irregularity index, intercanine width, intermolar width, arch length, overjet, and overbite—were obtained. The groups were compared by 1-way analysis of variance (ANOVA). The results showed that, on a short-term basis (1 year), all 3 retention strategies had an equal capacity to retain the orthodontic treatment results. Small but significant differences were seen in mandibular intercanine width, mandibular arch length, and overbite groups 1 and 2. The authors asserted that this study was the first randomized controlled trial study to demonstrate that mandibular anterior stripping without additional retention methods was sufficient for successful retention, and that a positioner can be used in the permanent dentition as a successful short-term retention device.Reviewed by Vanessa Ku The aims of this randomized controlled trial were to evaluate and compare 3 retention methods after 1 year of orthodontic retention. Seventy-five patients were recruited and randomly assigned to 3 groups of 25: a vacuum-formed retainer in the maxilla and bonded canine-to-canine retainer in the mandible, a vacuum-formed retainer in the maxilla combined with stripping of the 10 proximal surfaces of the mandibular anterior teeth, and a prefabricated positioner covering the teeth in the maxilla and the mandible. The inclusion criteria were treatment plan involving extraction of 4 premolars, space deficiencies in both jaws, Class I molar relationship or 3-mm anterior-posterior deviation, permanent dentition, and no prior orthodontic treatment. All subjects underwent fixed straight-wire appliance treatment by 1 orthodontist. Dental casts were obtained at 3 times: before treatment, immediately after treatment, and after 12 months of retention. Six measurements—Little’s irregularity index, intercanine width, intermolar width, arch length, overjet, and overbite—were obtained. The groups were compared by 1-way analysis of variance (ANOVA). The results showed that, on a short-term basis (1 year), all 3 retention strategies had an equal capacity to retain the orthodontic treatment results. Small but significant differences were seen in mandibular intercanine width, mandibular arch length, and overbite groups 1 and 2. The authors asserted that this study was the first randomized controlled trial study to demonstrate that mandibular anterior stripping without additional retention methods was sufficient for successful retention, and that a positioner can be used in the permanent dentition as a successful short-term retention device. Reviewed by Vanessa Ku Effect of glucocorticoids on osteoclasts and bone resorptionSøe K, Delaissé JM. Glucocorticoids maintain human osteoclasts in the active mode of their resorption cycle. J Bone Miner Res 2010;25:2184-92Glucocorticoids (GCs) are widely used immune suppressants that can lead to bone loss. Previous studies have shown that high doses of GCs impair the function of osteoblasts, therefore having a negative impact on bone formation. However, the impairment of osteoblasts alone does not explain a rapid increase in fracture risk in the first 3 to 6 months of treatment. This study examined the effect of GCs on osteoclasts (OCs) and bone resorption. Mature human OCs were generated from CD14+ cells in the presence of M-CSF and RANKL and then seeded on bone slices with the addition of 1.6 μM of prednisolone in the experimental group. The results showed that GCs act directly on OCs and change the morphology of resorption lacunae. No difference was found in the total resorbed bone surface, and metabolic activity was either unaffected or negatively affected in the experimental group. With GCs, there was a 30% increase in the number of deeper and elongated trenches, an increase in TRACP (OCs activity marker), a 3-times increase in CTX levels (OC collagenolysis activity marker), and less collagen left over at the bottom of the excavations. Exposure to GCs changes the resorption pattern of OCs from alternating between resorption and migration to continuous erosion of the bone surface. This behavioral change is thought to occur through enhanced collagenolysis, ensuring prolonged contact between OCs and mineral components. The authors concluded that the change in osteoclastic resorption mode from intermittent to continuous might contribute to the early bone fragilization of patients treated with GCs.Reviewed by Ga Lee Søe K, Delaissé JM. Glucocorticoids maintain human osteoclasts in the active mode of their resorption cycle. J Bone Miner Res 2010;25:2184-92Glucocorticoids (GCs) are widely used immune suppressants that can lead to bone loss. Previous studies have shown that high doses of GCs impair the function of osteoblasts, therefore having a negative impact on bone formation. However, the impairment of osteoblasts alone does not explain a rapid increase in fracture risk in the first 3 to 6 months of treatment. This study examined the effect of GCs on osteoclasts (OCs) and bone resorption. Mature human OCs were generated from CD14+ cells in the presence of M-CSF and RANKL and then seeded on bone slices with the addition of 1.6 μM of prednisolone in the experimental group. The results showed that GCs act directly on OCs and change the morphology of resorption lacunae. No difference was found in the total resorbed bone surface, and metabolic activity was either unaffected or negatively affected in the experimental group. With GCs, there was a 30% increase in the number of deeper and elongated trenches, an increase in TRACP (OCs activity marker), a 3-times increase in CTX levels (OC collagenolysis activity marker), and less collagen left over at the bottom of the excavations. Exposure to GCs changes the resorption pattern of OCs from alternating between resorption and migration to continuous erosion of the bone surface. This behavioral change is thought to occur through enhanced collagenolysis, ensuring prolonged contact between OCs and mineral components. The authors concluded that the change in osteoclastic resorption mode from intermittent to continuous might contribute to the early bone fragilization of patients treated with GCs.Reviewed by Ga Lee Glucocorticoids (GCs) are widely used immune suppressants that can lead to bone loss. Previous studies have shown that high doses of GCs impair the function of osteoblasts, therefore having a negative impact on bone formation. However, the impairment of osteoblasts alone does not explain a rapid increase in fracture risk in the first 3 to 6 months of treatment. This study examined the effect of GCs on osteoclasts (OCs) and bone resorption. Mature human OCs were generated from CD14+ cells in the presence of M-CSF and RANKL and then seeded on bone slices with the addition of 1.6 μM of prednisolone in the experimental group. The results showed that GCs act directly on OCs and change the morphology of resorption lacunae. No difference was found in the total resorbed bone surface, and metabolic activity was either unaffected or negatively affected in the experimental group. With GCs, there was a 30% increase in the number of deeper and elongated trenches, an increase in TRACP (OCs activity marker), a 3-times increase in CTX levels (OC collagenolysis activity marker), and less collagen left over at the bottom of the excavations. Exposure to GCs changes the resorption pattern of OCs from alternating between resorption and migration to continuous erosion of the bone surface. This behavioral change is thought to occur through enhanced collagenolysis, ensuring prolonged contact between OCs and mineral components. The authors concluded that the change in osteoclastic resorption mode from intermittent to continuous might contribute to the early bone fragilization of patients treated with GCs. Reviewed by Ga Lee Upper airway length and sleep apneaSusarla SM, Abramson ZR, Dodson TB, Kaban LB. Cephalometric measurement of upper airway length correlates with the presence and severity of obstructive sleep apnea. J Oral Maxillofac Surg 2010;68:2846-55Obstructive sleep apnea (OSA) is a breathing disorder characterized by recurrent episodic collapses of the upper airway and is associated with increases in resistance to airflow in the pharyngeal airway. Previous studies have established a correlation between upper airway length (UAL), measured on computed tomograms, with the presence and severity of OSA. However, using computed tomography scans to evaluate OSA can be costly, inconvenient, and excessive in radiation exposure. The aims of this study were to measure UAL on lateral cephalograms and to assess its relationship with the presence and severity of OSA. The authors hypothesized that UAL, measured along the long axis of the airway from the posterior palate to the superior hyoid would be longer in patients with OSA. With a case-control study design, 96 adults with OSA and 56 controls with skeletal Class II malocclusion without OSA were enrolled. The respiratory disturbance index (RDI) was used to measure disease severity. Bivariate analysis indicated that OSA subjects were predominately older and male, and had a higher body mass index, longer and narrower airway, longer hyoid-mandible distance, and longer soft palates. UAL was significantly longer in patients with OSA and is a predictor of OSA in both men and women, with UAL of ≥72 mm in men and ≥62 mm in women. UAL strongly correlated with RDI in men and moderately correlated with RDI in women. The results demonstrated high sensitivity and high specificity of UAL for the diagnosis of OSA. The authors recommended that UAL should be included in the routine cephalometric measurements for evaluating and following patients with OSA.Reviewed by Betty Chen Susarla SM, Abramson ZR, Dodson TB, Kaban LB. Cephalometric measurement of upper airway length correlates with the presence and severity of obstructive sleep apnea. J Oral Maxillofac Surg 2010;68:2846-55Obstructive sleep apnea (OSA) is a breathing disorder characterized by recurrent episodic collapses of the upper airway and is associated with increases in resistance to airflow in the pharyngeal airway. Previous studies have established a correlation between upper airway length (UAL), measured on computed tomograms, with the presence and severity of OSA. However, using computed tomography scans to evaluate OSA can be costly, inconvenient, and excessive in radiation exposure. The aims of this study were to measure UAL on lateral cephalograms and to assess its relationship with the presence and severity of OSA. The authors hypothesized that UAL, measured along the long axis of the airway from the posterior palate to the superior hyoid would be longer in patients with OSA. With a case-control study design, 96 adults with OSA and 56 controls with skeletal Class II malocclusion without OSA were enrolled. The respiratory disturbance index (RDI) was used to measure disease severity. Bivariate analysis indicated that OSA subjects were predominately older and male, and had a higher body mass index, longer and narrower airway, longer hyoid-mandible distance, and longer soft palates. UAL was significantly longer in patients with OSA and is a predictor of OSA in both men and women, with UAL of ≥72 mm in men and ≥62 mm in women. UAL strongly correlated with RDI in men and moderately correlated with RDI in women. The results demonstrated high sensitivity and high specificity of UAL for the diagnosis of OSA. The authors recommended that UAL should be included in the routine cephalometric measurements for evaluating and following patients with OSA.Reviewed by Betty Chen Obstructive sleep apnea (OSA) is a breathing disorder characterized by recurrent episodic collapses of the upper airway and is associated with increases in resistance to airflow in the pharyngeal airway. Previous studies have established a correlation between upper airway length (UAL), measured on computed tomograms, with the presence and severity of OSA. However, using computed tomography scans to evaluate OSA can be costly, inconvenient, and excessive in radiation exposure. The aims of this study were to measure UAL on lateral cephalograms and to assess its relationship with the presence and severity of OSA. The authors hypothesized that UAL, measured along the long axis of the airway from the posterior palate to the superior hyoid would be longer in patients with OSA. With a case-control study design, 96 adults with OSA and 56 controls with skeletal Class II malocclusion without OSA were enrolled. The respiratory disturbance index (RDI) was used to measure disease severity. Bivariate analysis indicated that OSA subjects were predominately older and male, and had a higher body mass index, longer and narrower airway, longer hyoid-mandible distance, and longer soft palates. UAL was significantly longer in patients with OSA and is a predictor of OSA in both men and women, with UAL of ≥72 mm in men and ≥62 mm in women. UAL strongly correlated with RDI in men and moderately correlated with RDI in women. The results demonstrated high sensitivity and high specificity of UAL for the diagnosis of OSA. The authors recommended that UAL should be included in the routine cephalometric measurements for evaluating and following patients with OSA. Reviewed by Betty Chen Expanding sutures with continuous forcesLiu SS, Kyung HM, Buschang PH. Continuous forces are more effective than intermittent forces in expanding sutures. Eur J Orthod 2010;32:371-80; e-pub, January 2010The authors reported greater sutural separation and bone formation with continuous forces vs intermittent forces in a suture-expansion study involving juvenile male New Zealand white rabbits. A 50-g expansion force was generated by a nickel-titanium open-coil spring placed between 2 titanium miniscrew implants. These implants were located 4 to 5 mm from the midsagittal suture on the dorsum of the cranium. One group (n = 7) had the force applied continuously for 29 consecutive days. The second group (n = 7) had the force applied intermittently (5 days on, 1 day off) for 29 days. Two fluorescent bone labels, oxytetracycline and calcein, were administered to all animals at various times during the study to quantify new bone formation. The continuous group averaged 1.3 mm of sutural separation, and the intermittent group showed 0.8 mm of separation. The 4 one-day breaks in the intermittent group resulted in a 61% sutural opening compared with the continuous group. Since forces were applied for 86% of the time in the intermittent group, the authors calculated a relapse of 25% and cited the recoil of stretched collagen fibers as reasons for relapse. Between days 7 and 17, the intermittent group showed 59% as much mineral apposition and 61% as much bone formation; sutural bone formation was proportional to sutural separation. The authors mentioned other mineralized tissue adaptation studies with long bones that showed greater endocortical and periosteal activity under oscillating loads. However, this study suggests that, for sutural bone growth, continuous forces are more effective.Reviewed by Jared T. Lee Liu SS, Kyung HM, Buschang PH. Continuous forces are more effective than intermittent forces in expanding sutures. Eur J Orthod 2010;32:371-80; e-pub, January 2010The authors reported greater sutural separation and bone formation with continuous forces vs intermittent forces in a suture-expansion study involving juvenile male New Zealand white rabbits. A 50-g expansion force was generated by a nickel-titanium open-coil spring placed between 2 titanium miniscrew implants. These implants were located 4 to 5 mm from the midsagittal suture on the dorsum of the cranium. One group (n = 7) had the force applied continuously for 29 consecutive days. The second group (n = 7) had the force applied intermittently (5 days on, 1 day off) for 29 days. Two fluorescent bone labels, oxytetracycline and calcein, were administered to all animals at various times during the study to quantify new bone formation. The continuous group averaged 1.3 mm of sutural separation, and the intermittent group showed 0.8 mm of separation. The 4 one-day breaks in the intermittent group resulted in a 61% sutural opening compared with the continuous group. Since forces were applied for 86% of the time in the intermittent group, the authors calculated a relapse of 25% and cited the recoil of stretched collagen fibers as reasons for relapse. Between days 7 and 17, the intermittent group showed 59% as much mineral apposition and 61% as much bone formation; sutural bone formation was proportional to sutural separation. The authors mentioned other mineralized tissue adaptation studies with long bones that showed greater endocortical and periosteal activity under oscillating loads. However, this study suggests that, for sutural bone growth, continuous forces are more effective.Reviewed by Jared T. Lee The authors reported greater sutural separation and bone formation with continuous forces vs intermittent forces in a suture-expansion study involving juvenile male New Zealand white rabbits. A 50-g expansion force was generated by a nickel-titanium open-coil spring placed between 2 titanium miniscrew implants. These implants were located 4 to 5 mm from the midsagittal suture on the dorsum of the cranium. One group (n = 7) had the force applied continuously for 29 consecutive days. The second group (n = 7) had the force applied intermittently (5 days on, 1 day off) for 29 days. Two fluorescent bone labels, oxytetracycline and calcein, were administered to all animals at various times during the study to quantify new bone formation. The continuous group averaged 1.3 mm of sutural separation, and the intermittent group showed 0.8 mm of separation. The 4 one-day breaks in the intermittent group resulted in a 61% sutural opening compared with the continuous group. Since forces were applied for 86% of the time in the intermittent group, the authors calculated a relapse of 25% and cited the recoil of stretched collagen fibers as reasons for relapse. Between days 7 and 17, the intermittent group showed 59% as much mineral apposition and 61% as much bone formation; sutural bone formation was proportional to sutural separation. The authors mentioned other mineralized tissue adaptation studies with long bones that showed greater endocortical and periosteal activity under oscillating loads. However, this study suggests that, for sutural bone growth, continuous forces are more effective. Reviewed by Jared T. Lee Pulpal vitality of traumatized maxillary incisorsBauss O, Schäfer W, Sadat-Khonsari R, Knösel M. Influence of orthodontic extrusion on pulpal vitality of traumatized maxillary incisors. J Endod 2010;36:203-7; e-pub, December 2009This retrospective study aimed to investigate the effects of orthodontic extrusion on the pulpal vitality of previously traumatized maxillary incisors. Patients were selected at 3 private orthodontic practices. Three groups were compared. Group 1 (n = 77 teeth) underwent orthodontic treatment to extrude a previously traumatized and vital maxillary incisor. Group 2 included orthodontic patients with no trauma history (n = 400), and group 3 had traumatized teeth with no orthodontic treatment (n = 193). Groups 1 and 3 were further subdivided into subgroups: periodontal injuries (subluxation, extrusion, lateral luxation, and intrusive luxation) and hard-tissue lesions (fracture of enamel or enamel and dentin). Pulpal vitality was diagnosed by using crown color, cryogenic spray, and periapical and panoramic radiographs. Differences between the groups were tested with the chi-square test and α = 0.05. Greater losses of vitality were found in the orthodontics and trauma group with periodontal injuries compared with the orthodontic group (P <0.001) and the trauma group (P <0.004). No differences were found between the central and lateral incisors or in hard-tissue lesions with or without orthodontic treatment. The authors concluded that maxillary incisors were in more danger of pulpal necrosis if they had a history of periodontal trauma. They also recommended the use lighter extrusive forces during treatment. The frequency of devitalization was small (9.1%, 0.5%, and 1.6%, respectively, in the 3 groups). Further research with larger groups of patients is needed to increase the statistical power.Reviewed by Brendan Smith Bauss O, Schäfer W, Sadat-Khonsari R, Knösel M. Influence of orthodontic extrusion on pulpal vitality of traumatized maxillary incisors. J Endod 2010;36:203-7; e-pub, December 2009This retrospective study aimed to investigate the effects of orthodontic extrusion on the pulpal vitality of previously traumatized maxillary incisors. Patients were selected at 3 private orthodontic practices. Three groups were compared. Group 1 (n = 77 teeth) underwent orthodontic treatment to extrude a previously traumatized and vital maxillary incisor. Group 2 included orthodontic patients with no trauma history (n = 400), and group 3 had traumatized teeth with no orthodontic treatment (n = 193). Groups 1 and 3 were further subdivided into subgroups: periodontal injuries (subluxation, extrusion, lateral luxation, and intrusive luxation) and hard-tissue lesions (fracture of enamel or enamel and dentin). Pulpal vitality was diagnosed by using crown color, cryogenic spray, and periapical and panoramic radiographs. Differences between the groups were tested with the chi-square test and α = 0.05. Greater losses of vitality were found in the orthodontics and trauma group with periodontal injuries compared with the orthodontic group (P <0.001) and the trauma group (P <0.004). No differences were found between the central and lateral incisors or in hard-tissue lesions with or without orthodontic treatment. The authors concluded that maxillary incisors were in more danger of pulpal necrosis if they had a history of periodontal trauma. They also recommended the use lighter extrusive forces during treatment. The frequency of devitalization was small (9.1%, 0.5%, and 1.6%, respectively, in the 3 groups). Further research with larger groups of patients is needed to increase the statistical power.Reviewed by Brendan Smith This retrospective study aimed to investigate the effects of orthodontic extrusion on the pulpal vitality of previously traumatized maxillary incisors. Patients were selected at 3 private orthodontic practices. Three groups were compared. Group 1 (n = 77 teeth) underwent orthodontic treatment to extrude a previously traumatized and vital maxillary incisor. Group 2 included orthodontic patients with no trauma history (n = 400), and group 3 had traumatized teeth with no orthodontic treatment (n = 193). Groups 1 and 3 were further subdivided into subgroups: periodontal injuries (subluxation, extrusion, lateral luxation, and intrusive luxation) and hard-tissue lesions (fracture of enamel or enamel and dentin). Pulpal vitality was diagnosed by using crown color, cryogenic spray, and periapical and panoramic radiographs. Differences between the groups were tested with the chi-square test and α = 0.05. Greater losses of vitality were found in the orthodontics and trauma group with periodontal injuries compared with the orthodontic group (P <0.001) and the trauma group (P <0.004). No differences were found between the central and lateral incisors or in hard-tissue lesions with or without orthodontic treatment. The authors concluded that maxillary incisors were in more danger of pulpal necrosis if they had a history of periodontal trauma. They also recommended the use lighter extrusive forces during treatment. The frequency of devitalization was small (9.1%, 0.5%, and 1.6%, respectively, in the 3 groups). Further research with larger groups of patients is needed to increase the statistical power. Reviewed by Brendan Smith