A radiographic comparison of apical root resorption after orthodontic treatment with a standard edgewise and a straight-wire edgewise technique

Clinical risk factors caused by third molar levelling following extraction of a mandibular second molar

BACKGROUND/OBJECTIVES

Mandibular second molar (MdM2) is often lost, and its space is filled with a bridge or implant. MdM2 extraction followed by orthodontic treatment protracting mandibular third molar (MdM3) towards the MdM2 position may overcome the missing of MdM2. The objectives of our study were to describe the outcome of the procedure and examined clinical risk factors such as external apical root resorption (EARR) and alveolar bone loss (ABL), as the indicators of poor orthodontic treatment outcomes.

MATERIALS/METHODS

This retrospective study included 70 cases in 56 patients who received orthodontic treatment at Tokyo Medical and Dental University Hospital between 2007 and 2018. Multi-bracket appliances were used in all patients for MdM3 protraction. Using linear mixed effects models, EARR and ABL were regressed on various factors, including panoramic and cephalometric variables.

RESULTS

With the mean treatment duration of 1040.4 ± 441.8 days, MdM2 space closure was achieved in 92.8% (65 cases). The ANB angle (P = .023) and the use of temporary anchorage devices (TADs) (P = .021) were significantly associated with the greater EARR, while the mandibular plane angle (P = .033) was associated with the greater ABL. MdM3 protraction using the fixed appliances resulted in the closure of MdM2 space in > 90% of cases without evident root resorption.

LIMITATION

There is a possibility of residual confounding due to the nature of observational study.

CONCLUSION/IMPLICATION

Orthodontic treatment of MdM3 protraction may be a feasible strategy to close the space of the missing MdM2.

Panoramic evaluation of external root resorption in mandibular molars during orthodontic treatment: a comparison between root-filled and vital teeth treated with fixed appliances or clear aligners

BACKGROUND

This investigation compared the extent of external apical root resorption (EARR) in root-filled teeth (RFT) and their contralateral vital pulp teeth (VPT) counterparts during orthodontic treatment (OT) with clear aligner (CA) treatment or fixed appliance (FA) treatment.

METHODS

Sixty-six patients with similar baseline American Board of Orthodontics (ABO) discrepancy index scores were divided into two groups: 37 patients (21 females, 16 males; mean age 17.45 ± 2.67 years) in the FA group, and 29 patients (18 females, 11 males; mean age 18.33 ± 1.96 years) in the CA group. Digital panoramic radiographs captured pre- and post-OT were used to measure tooth lengths and root surface measurements in mandibular molars. EARR in both RFT and contralateral VPT was evaluated pre- and post-OT. Statistical analysis employed paired t-tests, independent t-tests, and analysis of covariance (ANCOVA) (p < .05).

RESULTS

All teeth exhibited varying degrees of EARR following OT. FA treatment resulted in significantly longer treatment duration (p < .05) and greater EARR compared to CA treatment (p < .05). Moreover, statistically significant differences in EARR were observed within both groups between RFT and VPT (p < .05).

CONCLUSIONS

Comparison of pre- and post-OT radiographs revealed different degrees of EARR in all teeth. CA treatment resulted in less frequent and less severe EARR compared to FA treatment. RFT demonstrated greater resistance to EARR than VPT in both treatment groups.

Impact of molar teeth distalization by clear aligners on maxillary alveolar bone thickness and root resorption: a three‑dimensional study

OBJECTIVE

This study aimed to evaluate the impact of molar teeth distalization movement by clear aligners on changes in the alveolar bone thickness and orthodontically induced inflammatory root resorption (OIIRR) in maxillary molars using conebeam computed tomography (CBCT).

MATERIALS AND METHODS

Three-dimensional CBCT scans of 35 adult patients (one hundred forty maxillary molars) with pre-designed selection criteria and a mean age of 24.4 ± 7.1 years were included. The measured parameters, including alveolar bone thickness for maxillary molars and root resorption (OIIRR), were analyzed using pre-and post-treatment CBCT (T0 and T1, respectively) with Invivo 6.0 software.

RESULT

Post-treatment, relevant statistically significant changes included deposition of bone in the average palatal surface of the 1st molars. The reduction of bone was seen in the average buccal surface of the first molars and both surfaces of the second molars. Regarding root length after treatment, the average maxillary 1st molar roots showed significant OIIRR (p < 0.001).

CONCLUSION

Clear aligner treatment could effectively reduce the incidence of alveolar bone thickness reduction and OIIRR in treating Class II malocclusions compared to conventional braces, as shown in previous studies. This research will aid in fully grasping the benefits of clear aligners.

Effects of Low-Level Laser Therapy and Bracket Systems on Root Resorption during Orthodontic Treatment: A Randomized Clinical Trial

This study aimed to assess the outcomes of low-level laser therapy (LLLT) with the conventional bracket (CB) and self-ligating (SL) bracket systems on root resorption (RR) during orthodontic treatment. A total of 32 patients were included in this randomized clinical trial. All the patients were randomly divided into four individual groups (SLL: self-ligating laser, CBL: conventional bracket laser, SLNL: self-ligating non-laser, CBNL: conventional bracket non-laser). RR was measured from the cone-beam computed tomography (CBCT) radiographs which were taken at two stages of the orthodontic treatment: pre-treatment (T1) and after leveling and alignment stage (T2). Wilcoxon rank test for the comparison was conducted to compare the RR at T1 and T2 stages within each group and showed a significant difference (p < 0.05) for various variables. Mann Whitney test compared the RR in laser and non-laser groups irrespective of the bracket systems and exhibited no significant differences except the left lateral incisor. Moreover, CB and SL groups showed no significant difference in RR among any tooth. Kruskal Wallis test was performed to compare the RR among all groups which presented no significant differences. LLLT and bracket systems have no consequences on RR until the leveling and alignment stage of orthodontic treatment.

A quantitative three-dimensional comparative study of alveolar bone changes and apical root resorption between clear aligners and fixed orthodontic appliances

BACKGROUND

This study aimed to evaluate and compare the alveolar bone changes and to investigate the prevalence and severity of orthodontically induced inflammatory root resorption (OIIRR) of maxillary incisors in patients who received treatment with clear aligners (CA) versus conventional fixed appliances (FA), using cone-beam computed tomography (CBCT).

METHODS

One hundred sixty maxillary incisors from 40 patients with similar baseline characteristics based on the American Board of Orthodontics discrepancy index scores were divided into the CA and FA groups. The dentoalveolar quantitative changes were analyzed using pre- (T0) and post-treatment (T1) CBCT. The measured parameters included alveolar bone thickness (ABT), alveolar bone height (ABH), root length (OIIRR), and maxillary incisor inclinations.

RESULTS

Post-treatment, the average palatal and total ABT significantly decreased in central and lateral incisors in the FA group. In contrast, the CA group's average labial ABT of the lateral incisors decreased considerably. Regarding the ABH, both groups showed significant labial and palatal marginal bone resorption. In both groups, root lengths significantly decreased after treatment (p < 0.005). The inter-group comparison revealed that ABT and root length had significantly decreased in the FA group compared to the CA group, while the ABH showed no significant difference between the two groups. The mean absolute reductions of ABT and OIIRR in the CA group were significantly less (- 0.01 ± 0.89 and 0.31 ± 0.42) than those in the FA group (0.20 ± 0.82 and 0.68 ± 0.97), respectively.

CONCLUSIONS

CA and FA treatments appear to cause a significant ABT reduction and a statistically significant increased OIIRR in the maxillary incisor region, with a greater extent expected with FA treatment. However, the increased OIIRR values in the majority of both groups' cases were not clinically significant. Both treatment modalities resulted in a significant ABH reduction, with the highest found in the labial side of lateral incisors in the CA group.

Are asthma and allergy associated with increased root resorption following orthodontic treatment? A meta-analysis

OBJECTIVE

The aim of this study is to systematically investigate the available evidence from human studies regarding the association of asthma and/or allergy with EARR.

MATERIALS AND METHODS

Unrestricted searches in 6 databases and manual searching were performed up to May 2022. We looked for data on EARR after orthodontic treatment in patients with/without asthma or allergy. Relevant data were extracted, and the risk of bias was assessed. An exploratory synthesis was carried out using the random effects model, and the overall quality of the evidence was assessed with the Grades of Recommendation, Assessment, Development, and Evaluation.

RESULTS

From the initially retrieved records, nine studies met the inclusion criteria (three cohort and six case-control). Overall, increased EARR was observed in the individuals with allergies in their medical history (Standardised Mean Difference [SMD]: 0.42, 95% Confidence Interval [CI]: 0.19 to 0.64). No difference in EARR development was observed among individuals with or without a medical history of asthma (SMD: 0.20, 95% CI: -0.06 to 0.46). The quality of available evidence, excluding studies at high risk, was rated as moderate for the exposure to allergy, and low for the exposure to asthma.

CONCLUSION

Increased EARR was noted in individuals with allergies compared to the control group, while no difference was observed for individuals with asthma. Until more data become available, good practice would suggest that it is important to identify patients with asthma or allergy and consider the possible implications.

Effect of Serum Level of Vitamin D on External Apical Root Resorption in Maxillary Anterior Teeth in Patients under Fixed Orthodontic Treatment

Introduction

This study aimed to assess the effect of serum level of vitamin D on external apical root resorption (EARR) in maxillary anterior teeth in patients under fixed orthodontic treatment.

Materials and Methods

This retrospective cohort was conducted on patients under fixed orthodontic treatment who were between 12 to 30 years of age. All patients underwent the same treatment technique by the same orthodontist using a 0.022 MBT system. EARR in maxillary anterior teeth was evaluated on pre- and postoperative panoramic radiographs. Blood samples were also collected from patients, and their serum level of vitamin D was measured after the completion of treatment. Data were analyzed by independent t-test and Chi-square test (alpha = 0.05).

Results

A reduction in root length was noted in all patients, which was significant (P < 0.0001); 75% of patients showed EARR in at least one maxillary incisor. EARR had no significant correlation with the serum level of vitamin D (P=0.423).

Conclusions

Serum level of vitamin D had no significant correlation with the occurrence of EARR. However, the high prevalence of EARR calls for measures to minimize it.

The influence of bracket torque on external apical root resorption in bimaxillary protrusion patients: a retrospective study

Background

To evaluate the difference in root resorption between standard torque self-ligating brackets and high torque self-ligating brackets in bimaxillary protrusion patients after orthodontic treatment.

Methods

Pre-treatment and post-treatment Cone beam computed tomography (CBCT) of 32 patients (16 treated with the high torque DamonQ 0.022″ bracket and 16 with the 0.022″ standard torque self-ligating bracket) were selected. The first premolars were extracted from all patients before treatment. After mini-screw implants were inserted into the buccal region between the second premolar and first molar, 150 g of force was applied to retract the upper and lower anterior teeth to close the extraction space on each side. CBCT images of all patients were taken before and after treatment. Three-dimensional reconstruction of the maxillary central incisor, lateral incisor and canine was conducted with Mimics 20.0 software. The volumes of the roots were calculated using Gomagics Studio 12.0 software. The differences between the pre-treatment and post-treatment root volumes were statistically evaluated with a paired-samples t-test.

Results

There was no statistically significant difference in root resorption degree between the two kinds of torque brackets. The patient’s degree of root resorption in the high torque self-ligating group was greater than that in the standard torque group.

Conclusions

There was no significant difference in root external apical resorption between the high torque self-ligating brackets and the standard torque self-ligating brackets in bimaxillary protrusion patients.

An Assessment of the Effects of Orthodontic Treatment after Apexification of Traumatized Immature Permanent Teeth: A Retrospective Study

INTRODUCTION

Root resorption may occur in traumatized necrotic teeth that have undergone apexification after orthodontic treatment. This study examined the effects of orthodontic treatment on the outcome of apexification.

METHODS

This retrospective study included 36 children presenting with anterior permanent traumatized teeth with immature roots who were treated by apexification and root canal treatment. The orthodontic group consisted of 17 children with 24 teeth that were subjected to orthodontic treatment after apexification. The control group consisted of 19 children with 21 teeth that underwent only apexification without orthodontic treatment. Almost half of the teeth in both groups underwent apexification with calcium hydroxide, whereas the other half were treated with mineral trioxide aggregate. The effects of sex, stage of root development, and apexification material on the outcomes of apexification were analyzed and compared between the 2 groups.

RESULTS

Apexification was successful in 88% of cases after at least 5 years of follow-up. Neither apexification technique nor sex had a significant effect on treatment outcome. The stage of root development had a positive effect on outcome, although it was not statistically significant. Some root resorption (average = 0.3 mm) was observed after orthodontic treatment, whereas teeth that underwent apexification without orthodontic treatment exhibited some root elongation (average = 0.1 mm). This difference was highly significant.

CONCLUSIONS

Minor root resorption was observed in the orthodontic group compared with a minor increase in root length in the control group. Orthodontic movement of immature traumatized teeth after apexification appears to be safe.

Occlusal outcome after orthodontic treatment with preadjusted straight-wire and standard edgewise appliances : A retrospective cohort study

PURPOSE

Orthodontic fixed appliances have been proven to be effective in treating a wide variety of malocclusions, and different types of appliances have emerged during recent decades. However, the comparative effects of different appliances have not been adequately assessed. Thus, the aim was to assess the occlusal outcome of orthodontic treatment with preadjusted straight-wire (SWIRE) and standard edgewise (SEDGE) appliances.

METHODS

In all, 56 patients (mean age: 13.5 years; 45% male) receiving extraction-based treatment with either SWIRE or SEDGE appliances were included. Between-group differences in the occlusal outcome assessed with the American Board of Orthodontists Objective Grading System (ABO-OGS) and treatment duration were analyzed statistically at the 5% level.

RESULTS

The average ABO-OGS score was 31.3 ± 7.2 points and 34.0 ± 10.4 points in the SWIRE and SEDGE groups with no statistically significant difference between groups (P = 0.26). Treatment duration was significantly shorter in the SWIRE group compared to the SEDGE group, with an average difference of -6.8 months (95% confidence interval [95% CI] = -9.6 to -4.0 months; P < 0.001). Likewise, fewer visits were needed with SWIRE compared to SEDGE appliances with an average difference of -7.2 visits (95% CI = -10.3 to -4.2 visits; P < 0.001). Adjusting for the influence of any potential confounders did not considerably impact the results.

CONCLUSION

Similar treatment outcomes were observed after premolar extraction treatment with SWIRE and SEDGE appliances. On the other hand, SEDGE appliances were associated with prolonged treatment duration and more visits needed to complete treatment compared to SWIRE appliances.

Effect of orthodontic forces on root length of immature mandibular second premolars: a split-mouth randomized clinical trial

Objective:

To assess the effect of orthodontic forces on changes in root length of immature mandibular second premolars.

Methods:

Sixty-four mandibular second premolars (MSP) with immature apices (left and right sides) of 32 patients aged between 10 and 13 years were evaluated. Orthodontic treatment was started after obtaining periapical radiographs (T₁) from the MSPs of each patient. Brackets were bonded, except the ones of MSPs (left or right by random as control MSP, and the other side as test MSP). After 9-12 months, a second periapical radiograph (T₂) was obtained from the MSPs of each patient. Then, brackets were bonded to the control MSPs, which were not bonded before. After 18 ± 3 months, a third periapical radiograph (T₃) was obtained. Changes in root length were evaluated by using a new formula. The test and control MSPs at T₁, T₂ and T₃ were compared using repeated measures ANOVA and parametric tests. P-value smaller than 0.05 was statistically significant.

Results:

There was no significant difference between the test and control groups in the mean root length of MSP at T₁ (p= 0.48) and T₃ (p= 0.078). The root length at T₂ (p= 0.001) was significantly different between test and control MSPs, and the test group showed longer root length than the control group.

Conclusions:

Orthodontic force applied for leveling and alignment of immature MSPs may not have destructive effects on the roots, and may accelerates root formation in short-term. Normal root length was achieved at the end of root development.

A randomized trial on the effects of root resorption after orthodontic treatment using pulsating force

Background

An orthodontic device that moves teeth with pulsating force was invented and underwent a single center, controlled, clinical trial to test its safety and efficacy for treatment. The device has a custom-made thermo-plastic mouthpiece which fits over the teeth with an inflatable silicone element. A console that measures and controls the pulsating force level in real-time controls the air pressure that delivers a pulsating force. In this study, the effect of the device on root resorption during orthodontic treatment was evaluated using 3D cone beam computed tomography and compared with a control group of patients who received Invisalign treatment.

Methods

Twenty-eight subjects were enrolled in the investigational arm and 15 in the control group. Subjects were followed until the average score of the mandibular and maxillary teeth achieved a Little’s Irregularity Index of 1.5 mm or less.

Results

There were no adverse events reported throughout the study for either treatment arm. No clinically significant root resorption was observed for either group. The investigational device did not cause root resorption greater than the control group. Both devices produced a safety profile compared to current orthodontic techniques.

Conclusion

The investigational device did not produce more root resorption than similar conventional orthodontic appliances.

Trial registration

ClinicalTrials.gov, NCT03421886. Registered 12 January 2018 - Retrospectively registered.

Prevalence and severity of apical root resorption during orthodontic treatment with clear aligners and fixed appliances: a cone beam computed tomography study

Background

Fixed appliances have been the mainstream for orthodontic treatment, while clear aligners, such as Invisalign system, have become increasingly popular. The prevalence of apical root resorption (ARR) in patients with clear aligners is still controversial. The aim of this study was to investigate and compare the prevalence and severity of ARR in patients treated with clear aligners and fixed appliances using cone beam computed tomography (CBCT).

Materials and methods

A total of 373 roots from 70 subjects, with similar baseline characteristics and the ABO discrepancy index scores (i.e., treatment difficulty), were included into two groups: the clear aligners group (Invisalign, Align Technology, California, USA) and fixed appliances group (Victory Series; 3 M Unitek, California, USA). Root length of each anterior tooth was measured on the CBCT images by two blinded investigators. The ARR on each tooth was calculated as the difference of root length before and after orthodontic treatment. Chi-square test and paired t test was used to compare the ARR between the two groups as well as before and after orthodontic treatments.

Results

Prevalence of ARR in the clear aligners group (56.30%) was significantly lower than that in the fixed appliances group (82.11%) (P < 0.001). The severity of ARR in the clear aligners group (0.13 ± 0.47 mm) was significantly less than that in the fixed appliances group (1.12 ± 1.34 mm) (P < 0.001). The most severe ARR was found on the maxillary canine (1.53 ± 1.92 mm) and lateral incisor (1.31 ± 1.33 mm) in the fixed appliances group; the least ARR was found on the mandibular canine (− 0.06 ± 0.47 mm) and lateral incisor (0.04 ± 0.48 mm) in the clear aligners group (P < 0.001).

Conclusions

The prevalence and severity of ARR measured on CBCT in patients with clear aligners were less than those in patients with fixed appliances.

Apical root resorption after orthodontic treatment in patients with unilateral cleft lip and palate

OBJECTIVES

The aims of this retrospective longitudinal study were to present the incidence of external apical root resorption (EARR) in the maxillary anterior teeth of patients with complete unilateral cleft lip and palate (CUCLP) and to evaluate the influence of orthodontic treatment variables on the development of EARR.

MATERIAL AND METHODS

Forty-one patients with CUCLP participated in the study. Orthopantomograms (OPGs), taken before (T2) treatment with multiband orthodontic appliances (MBA), and periapical radiographs (PAs) of the maxillary anterior teeth taken at the end (T3) of orthodontic treatment (OT) were assessed for EARR.

RESULTS

The incidence of EARR at T3 (97.6%) was considerably higher than at T2 (51.2%). Central incisors and canines on the cleft side showed a significantly higher score (p < 0.01, p < 0.05 respectively) of EARR in comparison to the same group of teeth on the non-cleft side. Preexisting EARR and abnormal root morphology were identified as predisposing factors for EARR.

CONCLUSIONS

Patients with CUCLP treated with MBA have higher incidence of EARR on the maxillary anterior teeth of the cleft side. Severe EARR is rather rare but more often seen on central incisors of the cleft side.

CLINICAL RELEVANCE

As most of the patients with cleft lip and palate undergo a challenging and long-term OT with MBA, it is of importance to identify the predisposing factors related to the special anatomical features of the bone and teeth located in the cleft area, as well as the special OT needs of these patients.

Association of clinical variables and polymorphisms in RANKL, RANK, and OPG genes with external apical root resorption

OBJECTIVES

The aim of this study was to investigate the association of clinical variables and polymorphisms in the RANKL, RANK, and OPG genes with external apical root resorption (EARR).

METHODS

The sample was composed of 338 unrelated patients of both sexes, average age 14.9 years (range 8-21) with Class II Division 1 malocclusion, orthodontically treated. Periapical radiographs of the maxillary central incisor with the longer root (reference tooth) were taken before treatment and 6 months after starting treatment. DNA was extracted from buccal epithelial cells with the use of 10 mol/L ammonium acetate and 1 mmol/L EDTA. The analysis of 42 polymorphisms in the RANKL, RANK, and OPG genes was performed by means of real-time polymerase chain reaction. Univariate and multivariate analyzes were performed to verify the association of clinical and genetic variables with EARR (P <0.05).

RESULTS

The initial root length and patient age were associated with EARR. Considering the study of polymorphisms of RANKL, no significant association was found of genetic polymorphisms with EARR. For RANK polymorphisms, only rs12455775 was associated with EARR. Regarding OPG polymorphisms, an association of rs3102724, rs2875845, rs1032128, and rs3102728 with EARR was found. After multivariate analysis, the initial root length, rapid maxillary expansion, and rs3102724 of the OPG gene were associated with EARR.

CONCLUSIONS

Longer roots of upper central incisors and rapid maxillary expansion, as well as allele A of the rs3102724 polymorphism of the OPG gene, were associated with EARR in the study population.

The influence of bracket type on the external apical root resorption in class I extraction patients - a retrospective study

Background

The relationship between orthodontic treatment-related factors and EARR has never been fully answered. The aim of this study was to investigate whether conventional and passive self-ligating brackets affect the amount and severity of external apical root resorption (EARR) in withdrawal patients.

Methods

Ninety-eight patients were selected from department of orthodontic, hospital of stamotology, Wenzhou medical university. Patients received treatment with either a conventional edgewise appliance (n = 49, Mini, 3 M Unitek, USA) or a passive self-ligating bracket system (n = 49, Damon, Ormco, USA). EARR of the maxillary incisors was evaluated on panoramic radiographs at the before and end of orthodontic treatment, respectively. Intergroup comparisons of root resorption were performed with Mann-Whitney tests. The univariate and multivariate regression model was used to assess the appliance type, age, sex and duration of treatment on EARR.

Results

There was no significant difference in the amount of EARR between the two groups was found. Age and gender were not association with EARR, however, EARR was positively correlated with treatment duration.

Conclusions

The type of bracket did not influence the occurrence and severity of the external apical root resorption in class I extraction patients.

Ethnic differences in the root to crown ratios of the permanent dentition

OBJECTIVE

Root resorption due to orthodontic tooth movement may adversely affect the root-crown (R/C) ratios of permanent teeth, especially in patients with Short Root Anomaly (SRA), a poorly understood disorder affecting root development. Evaluation of SRA R/C ratios to normal dentition would facilitate diagnosis and orthodontic treatment planning. However, reference values are not available for all ethnicities. Our goal was to determine R/C ratios of permanent teeth and their relationship to gender and ethnicity.

SETTING/SAMPLE

A retrospective study of 333 patients (109 Caucasians, 112 African Americans and 112 Hispanics) from the University of Alabama at Birmingham School of Dentistry.

MATERIALS/METHODS

Root lengths and crown heights were measured from panoramic radiographs of 6241 teeth using modified Lind's method. A linear mixed model was used to compare the R/C ratios of teeth among subgroups (gender, ethnicity).

RESULTS

The mean R/C ratios varied from 1.80 to 2.21 for the maxillary teeth and 1.83-2.49 for the mandibular teeth. Gender differences in R/C ratios were found to be significant only for the lower central incisors (P < 0.05). Hispanics showed significantly lower ratios for most teeth compared to the other two groups (P < 0.05). There were significant differences in R/C ratios between African Americans and Caucasians in the upper lateral incisors, lower central incisors and lower first premolars (P < 0.05).

CONCLUSION

Our results suggest that ethnicity is an important factor in determining the R/C ratios of permanent teeth. Therefore, when diagnosing developmental conditions such as SRA, ethnic group-specific reference values should be considered.

Incisor root resorption in class II division 2 patients in relation to orthodontic treatment

Background/Objectives

The aims were 1. to analyse differences in the occurrence of orthodontic induced inflammatory root resorption (OIIRR) of the upper and lower incisors in Angle Class II division 2 patients, between patients treated with fixed appliance only (one-phase treatment group) and patients treated with removable appliance before treatment with fixed appliance (two-phase treatment group) and 2. to analyse differences in OIIRR between treatment time, age, gender, craniofacial morphology and deviations in the dentition for the two groups together.

Materials/Methods

Seventy-four subjects treated for Class II division 2 malocclusion were divided into two groups: 46 patients in the one-phase treatment group (28 girls, 18 boys, mean age 14.4) and 28 patients in the two-phase treatment group (18 girls, 10 boys, mean age 12.4) where 336 and 201 incisors were analysed respectively. OIIRR was assessed on intra oral radiographs, deviations of the dentition were assessed on orthopantomograms and the craniofacial morphology was assessed on lateral cephalograms. Differences were tested by Fisher Exact test, McNemar, and multiple regression analysis.

Results

The one-phase treatment group showed significantly more OIIRR for lower central incisors (P = 0.002) compared to the two-phase treatment group. For the both groups combined, boys showed more OIIRR than girls (P = 0.002) and patients with agenesis showed more OIIRR than patients without agenesis (P = 0.019) for the lower central incisors.

Conclusion

The results indicate that two-phase treatment modalities may be considered as an option for Angle Class II division 2 patients with enhanced risk for OIIRR.

Comparative study of root resorption of maxillary incisors in patients treated with lingual and buccal orthodontics

OBJECTIVE

To compare the magnitude of external apical root resorption (EARR) of maxillary incisors in patients with mild to moderate anterior crowding, treated with lingual and conventional (labial) orthodontics.

MATERIALS AND METHODS

The sample comprised 40 patients divided into two groups: lingual (20 patients) and conventional buccal brackets (20 patients). Patient ages ranged from 11 to 45 years, and the study included 12 men and 28 women. Apical root resorption was measured from periapical radiographs obtained at the beginning of treatment (T1) and at the end of the leveling phase (T2). Periapical radiographs were scanned and transferred to the CorelDraw X7 image-processing program, in which measurements of root lengths were performed. For intragroup and intergroup comparisons between the T1 and T2 phases, paired and independent t-tests, respectively, were used at 5% significance.

RESULTS

There was significant apical root resorption for all teeth evaluated; the magnitude of the EARR (T2-T1) ranged from -0.35 mm to -0.63 mm in the lingual group, and from -0.66 mm to -0.85 mm in the conventional group. Although there was an intergroup variation in the magnitude of EARR observed, no statistically significant differences were found. Neither group presented any teeth with resorption ≥1 mm.

CONCLUSIONS

The magnitude of apical root resorption in maxillary incisors in patients with anterior crowding was similar regardless of orthodontic technique, lingual or conventional. Both techniques resulting in an apical rounding considered clinically insignificant.

Cone-beam computed tomography for the assessment of root-crown ratios of the maxillary and mandibular incisors in a Korean population

Objective

This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root–crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT).

Methods

We included 672 Korean patients (141 men and 531 women; mean age, 27.2 ± 7.7 years) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships.

Results

Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age.

Conclusions

The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

Correlation Between Orthodontic Forces and Root Resorption – a Systematic Review of the Literature

Orthodontically induced external apical root resorption (OIEARR) is a major concern regarding periodontal status after nonsurgical orthodontic treatment. The aim of this study was to assess this sequel by a systematic review of published data. For assessment, we performed an electronic search of one database for comprehensive data, using keywords in different combinations: “root resorption”, “periodontics” and “nonsurgical orthodontic treatment”. We supplemented the results searching by hand in published journals and we cross-referenced with the accessed articles. Patients included in the results presented a good general health status, with no previous history of OIEARR and no other associated pathologies. Finally, twenty-three studies were selected and included in this review. A high prevalence (69–98%) and moderate severity of OIEARR (<5 mm and <1/3 from original root length) were reported. No difference in root resorption was found regarding the sex of the patients. A moderate positive correlation between treatment duration and root resorption was found. Also, a mild correlation regarding antero-posterior apical displacement and root resorption was found.

The treatment timing of labial inversely impacted maxillary central incisors: A prospective study

OBJECTIVE

To determine the timing of treatment for the labial inversely impacted maxillary central incisors.

METHODS

Twenty-eight patients (mean age, 8.2 years) with labial inversely impacted maxillary central incisors were divided into early-treated and later-treated groups according to their dental age. All of the patients were treated with a combination of surgery and orthodontic traction using the Guide rod appliance. Cone-beam computed tomography images were taken immediately after treatment for assessing the root morphology, root length, and alveolar bone loss. Sagittal slices were evaluated at the widest labial-lingual width of the tooth in the axial view. All variables were evaluated by Simplant 13.0 software (Materialise Dental NV, Leuven, Belgium).

RESULTS

The rank sum test indicated that the root length of two groups showed a statistically significant difference between the impacted and homonym tooth, with a shorter length in the impacted tooth (P < .05). The D-value (difference of root length between the impacted and homonym tooth) and alveolar bone loss on the labial side of the impacted incisor are significantly less in the early-treated groups when compared with the later-treated groups (P < .05). Spearman rank correlation analysis showed a statistically positive association between the treatment timing and D-value (r  =  .623, P < .05). The chi-square test for morphology of root apex indicated that the incidence of the root-apex-directed labial side is significantly higher in the later-treated groups when compared with the early-treated groups.

CONCLUSION

The labial inversely impacted maxillary central incisors should be treated early to promote root development by achieving a better morphology of root apex, thus reducing the risk of alveolar bone loss on the labial side.

Resorption of maxillary incisors after orthodontic treatment--clinical study of risk factors

INTRODUCTION

External apical root resorption (EARR) is one of the major problems associated with orthodontic treatment. Such lesions represent an iatrogenic risk that must be detected as early as possible, with regular radiological follow-up and appropriate therapeutic precautions. The causes and mechanisms leading to susceptibility to root resorption following the application of an orthodontic force are often not clear and are generally said to be of multifactorial origin. The aim of this clinical study was to analyze the factors linked to the occurrence of moderate to severe resorption (MSR) of upper incisors during orthodontic treatment in a group of Moroccan patients treated in the Dento-Facial Orthopedic Department of the Dental Consultation and Treatment Center (Centre de consultation et de traitements dentaires [CCTD]) in Rabat.

MATERIAL AND METHODS

A total of 82 patients (28% males, 72% females) aged between 12 and 27, with various malocclusions, who had been treated with fixed appliances for at least 1 year and for whom panoramic X-rays at the start, during and at the end of treatment were available, were selected randomly. The reduction in maxillary incisor root length was evaluated using resorption scores. The factors studied in relation to the risk of occurrence of MSR were: age, sex, treatment duration, extraction or non-extraction, type of malocclusion (Class I arch-length discrepancy, Class II, Class III), the vertical diagnosis (normal, supraocclusion, open bite), presence of dysfunction, impacted canines and root morphology. Statistical analysis was performed using SPSS software, version 18.0. Statistical tests used were: Kaplan-Meier analysis and the univariate and multivariate Cox models for the study of factors associated with MSR. The threshold of significance adopted was 0.05.

RESULTS

The factors that were significantly associated with the occurrence of MSR at the level of the upper incisors were: tooth type, with a greater risk for the lateral incisor (HR=3.2 95% CI [2.3-4.5] P<0.001), treatments with extraction (HR=1.64 95% CI [1.16-2.33] P<0.05), the presence of supraocclusion (HR=2.17 95% CI [1.33-3.53] P<0.05) or open bite (HR=3.12 95% CI [1.66-5.86] P<0.001) and root malformation (HR=1.5 95% CI [1.09-2.07] P<0.05). Age, sex, type of malocclusion, dysfunction and impaction of canines were not associated at a statistically significant level with the risk of occurrence of MSR of the upper incisors.

CONCLUSION

EARR is difficult to avoid; the orthodontist's role remains crucial in identifying risk factors so as to adopt a treatment strategy taking these factors into account. In our population, the risk of MSR in the upper incisors appeared to increase in treatments with extraction, situations of supraocclusion or open bite, and in the presence of root abnormalities. Finally, clinical recommendations for the prevention of the occurrence of MSR of the maxillary incisors are proposed, taking into account all the risk factors identified.

A posteriori registration and subtraction of periapical radiographs for the evaluation of external apical root resorption after orthodontic treatment

Purpose

Materials and Methods

Results

Conclusion

Root resorption of self-ligating and conventional preadjusted brackets in severe anterior crowding Class I patients: a longitudinal retrospective study

Background

To test the null hypothesis that there is no difference in the apical root resorption seen after orthodontic treatment with the conventional brackets and the self-ligating brackets.

Methods

Pre-treatment and post-treatment periapical radio-graphs of 70 patients, (35 treated with the Damon3 0.022” bracket and 35 with the 0.022” 3 M bracket) were studied. The long cone paralleling technique was used for all the radio-graphs. Any image distortion between the pre-treatment and post-treatment radio-graph was calculated and compensated for by using the crown length measurements, on the assumption that the crown length remains unaltered during the treatment period. Quantitative measurements of crown and root lengths for the maxillary and the mandibular central and lateral incisors were compared. Means and standard deviations for the percentage root resorption per tooth group were calculated. A paired t-test and non paired t-test analysis was performed to determine whether there was an appliance, treatment time, or initial age effect on the amount of root resorption seen after treatment.

Result

No statistically significant difference in root resorption between the two appliance systems was found. The patient’s degree of root resorption were graded as grade 1 and grade 2 in the self-ligating group which is more than the conventional group.

Conclusions

There was no significant difference in root resorption between self-ligating brackets and conventional brackets in severe crowding incisors subjects.

Radiographic comparison of apical root resorption after orthodontic treatment between bidimensional and Roth straight-wire techniques

Objective:

The aim of this study was to compare the amount of root resorption after orthodontic treatment between the bidimensional and the Roth straight-wire techniques. Another objective was to compare the amount of root resorption in the whole sample studied and record the prevalence of root resorption.

Materials and Methods:

The sample consisted of 40 patients (age ranged between 11 and 18 years) with Angle Class II division 1 malocclusions, treated nonextraction. Twenty patients were treated with bidimensional technique and 20 with a 0.018-inch Roth straight-wire technique. Root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs.

Results:

The results demonstrated that the bidimensional and Roth straight-wire groups showed significant root resorption after treatment, 1.11 (0.17) and 0.86 (0.05), respectively, P < 0.001. When comparing the amount of root shortening between the bidimensional and Roth straight-wire groups, there was no significant difference between the mean change from pre- to post-treatment between bidimensional group (mean = 1.00 ± 1.34) and Roth straight-wire group (mean = 0.88 ± 0.86), P = 0.63. Considering the whole sample, there was no root resoprtion in 32.5% of the analysed teeth. There was only mild resorption in 56.2%, moderate in 8.8% and severe in only 2.5% of the teeth.

Conclusions:

Treatment with the bidimensional technique did not produce an increase in the amount of root resorption. The prevalence and amount of root resorption was similar between bidimensional and Roth straight-wire techniques.

Comparing the effectiveness of the 0.018-inch versus the 0.022-inch bracket slot system in orthodontic treatment: study protocol for a randomized controlled trial

Background

Edgewise fixed orthodontic appliances are available in two different bracket slot sizes (0.018 and 0.022 inch). Both systems are used by clinicians worldwide with some orthodontists claiming the superiority and clinical advantages of one system over the other. However, the scientific evidence supporting this area is scarce and weak. This leaves the clinician’s choice of bracket slot system to clinical preference. We aim to compare the 0.018-inch and 0.022-inch pre-adjusted bracket slot systems in terms of the effectiveness of orthodontic treatment.

Methods/Design

This is a prospective, multicenter, randomized clinical trial, undertaken in the secondary care hospital environment in the NHS Tayside region of Scotland (United Kingdom). A total of 216 orthodontic patients will be recruited in three centers in secondary care hospitals in NHS Tayside. The participants will be randomly allocated to treatment with either the 0.018-inch or 0.022-inch bracket slot systems (n = 108 for each group) using Victory series™ conventional pre-adjusted bracket systems (3 M Unitek, Monrovia, United States). Baseline records and outcome data collected during and at the end of orthodontic treatment will be assessed. The primary outcome measures will be the duration of orthodontic treatment in the maxillary and mandibular arches. The secondary outcome measures will be the number of scheduled appointments for orthodontic treatment in the maxillary and mandibular arches, treatment outcome using Peer Assessment Rating index (PAR), orthodontically induced inflammatory root resorption (as measured using periapical radiographs) and the patient’s perception of wearing orthodontic appliances.

Discussion

The results from the current study will serve as evidence to guide the clinician in deciding whether the difference in bracket slot size has a significant impact on the effectiveness of orthodontic treatment.

Trial registration

Registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338.

Radiologically determined orthodontically induced external apical root resorption in incisors after non-surgical orthodontic treatment of class II division 1 malocclusion: a systematic review

This study aims to critically evaluate orthodontically induced external apical root resorption (OIEARR) in incisors of patients undergoing non-surgical orthodontic treatment of class II division 1 malocclusion by a systematic review of the published data. An electronic search of two databases was performed; the bibliographies of relevant articles were also reviewed. Studies were included if they examined the amount of OIEARR in incisors produced during non-surgical orthodontic treatment of individuals with class II division I malocclusion in the permanent dentition. Individuals had no previous history of OIEARR, syndromes, pathologies, or general diseases. Study selections, risk of bias assessment, and data extraction were performed in duplicate. Eight studies of moderate methodological quality were finally included. An increased prevalence (65.6% to 98.1%) and mild to moderate severity of OIEARR (<4 mm and <1/3 original root) were reported. No sex difference in root resorption was found. For the maxillary incisors, there was no evidence that either the central or lateral incisor was more susceptible to OIEARR. A weak to moderate positive correlation between treatment duration and root resorption, and anteroposterior apical displacement and root resorption was found. Current limited evidence suggests that non-surgical comprehensive orthodontic treatment to correct class II division 1 malocclusions causes increased prevalence and severity of OIEARR the more the incisor roots are displaced and the longer this movement takes.

The effect of orthodontic therapy on periodontal health: a review of the literature

Objectives. This review aims to evaluate the effect of orthodontic therapy on periodontal health. Data. Original articles that reported on the effect of orthodontic therapy on periodontal health were included. The reference lists of potentially relevant review articles were also sought. Sources. A literature search was conducted using the databases, Medline, EMBASE, Cochrane Library, Web of Science, Google Scholar, and Scopus databases for relevant studies. The search was carried out by using a combined text and the MeSH search strategies: using the key words in different combinations: “periodontal disease,” “orthodontics” and “root resorption.” This was supplemented by hand-searching in peer-reviewed journals and cross-referenced with the articles accessed. Articles published only in English language were included. Letters to the Editor, historical reviews and unpublished articles were not sought. Conclusions. Within the limitations of the present literature review, it was observed that there is a very close inter-relationship between the periodontal health and the outcome of orthodontic therapy.

Root resorption after leveling with super-elastic and conventional steel arch wires: a prospective study

BACKGROUND

The aim of this prospective study was to compare root resorption after the leveling phase of treatment, performed by either super-elastic or conventional multi-stranded stainless steel arch wires.

METHODS

From a total of 156 future orthodontic patients in a private clinic, 82 were included in the study after excluding those who earlier had orthodontic or endodontic treatment or signs of resorption. Patients were equally arbitrary allocated into two groups, where leveling was performed either with super-elastic heat-activated or conventional multi-stranded stainless steel arch wires. Root length loss was calculated using pre-treatment and post-leveling periapical radiographs.

RESULTS

The use of super-elastic arch wires did not significantly increase the severity of root resorption, except for tooth 31, while it reduced leveling time compared to conventional stainless steel wires. Crossbite of maxillary lateral incisors seemed to be a risk factor for resorption.

CONCLUSION

Incisor root resorption after leveling did not differ significantly between patients treated with super-elastic and conventional stainless steel arch wires, except for a mandibular incisor.

The effect of photobiomodulation on root resorption during orthodontic treatment

Photobiomodulation is used to accelerate tooth movement during orthodontic treatments. The changes in root morphology in a group of orthodontic patients who received photobiomodulation were evaluated using the cone beam computed tomography technique. The device used is called OrthoPulse, which produces low levels of light with a near infrared wavelength of 850 nm and an intensity of 60 mW/cm² continuous wave. Twenty orthodontic patients were recruited for these experiments, all with class 1 malocclusion and with Little’s Irregularity Index (>2 mm) in either of the arches. Root resorption was detected by measuring changes in tooth length using cone beam computed tomography. These changes were measured before the orthodontic treatment and use of low-level laser therapy and after finishing the alignment level. Little’s Irregularity Index for all the patients was calculated in both the maxilla and mandible and patients were divided into three groups for further analysis, which were then compared to the root resorption measurements. Our results showed that photobiomodulation did not cause root resorption greater than the normal range that is commonly detected in orthodontic treatments. Furthermore, no correlation between Little’s Irregularity Index and root resorption was detected.

Root resorption, treatment time and extraction rate during orthodontic treatment with self-ligating and conventional brackets

INTRODUCTION

This study determined the amount and severity of EARR (external apical root resorption) after orthodontic treatment with self-ligating (SL) and conventional (Non-SL) brackets. Differences regarding rate of extraction cases, appointments and treatment time were evaluated.

MATERIAL AND METHODS

213 patients with a mean age of 12.4 ± 2.2 years were evaluated retrospectively. The treatments were performed with SL brackets (n = 139, Smartclip, 3 M Unitek, USA) or Non-SL brackets (n = 74, Victory Series, 3 M Unitek, USA). Measurements of the crown and root length of the incisors were taken using panoramic radiographs. Three-factor analysis of variance (ANOVA) was performed for an appliance effect.

RESULTS

There was no difference between patients treated with Non-SL or SL brackets regarding the amount (in percentage) of EARR (Non-SL: 4.5 ± 6.6 vs. SL: 3.0 ± 5.6). Occurrence of severe EARR (sEARR) did also not differ between the two groups (Non-SL 0.5 vs. SL: 0.3). The percentage of patients with need of tooth extraction for treatment (Non SL: 8.1 vs. SL: 6.9) and the number of appointments (Non-SL: 12.4 ± 3.4 vs. SL: 13.9 ± 3.3) did not show any differences. The treatment time was shorter with Non-SL brackets (Non-SL: 18.1 ± 5.3 vs. SL: 20.7 ± 4.9 months).

CONCLUSIONS

This is the largest study showing that there is no difference in the amount of EARR, number of appointments and extraction rate between conventional and self-ligating brackets. For the first time we could demonstrate that occurrence of sEARR does not differ between the two types of brackets.

Cone-beam computed tomography evaluation of periodontal and bone support loss in extraction cases

Background

The aim of this study was to evaluate, in particular, whether bone resorption occurred at the extraction sites of a group of patients under orthodontic treatment, and, in general, whether extraction treatment predisposes patients to a greater degree of root resorption.

Methods

The study group comprised 12 class II division 1 malocclusion patients who underwent orthodontic treatment and extraction, and the control group comprised 10 class II division 1 patients who underwent orthodontic treatment without extraction. In both groups, treatments were carried out by the same operator using the same techniques. Cone-beam computed tomography performed before (T1) and after (T2) treatment was used to determine and compare the root length, the distance from the cementoenamel junction to the base of the defect and to the bone peak, the width of the defect and the buccolingual bone thickness.

Results

Root length was reduced following treatment in both groups, although to a statistically significantly greater extent in the study group. The buccolingual bone thickness was reduced after treatment in both groups, with no differences found between the study and control groups. The bone loss at the sites assessed was greater in the patients after extraction treatment, with a statistically significant difference revealed between the two groups. The site that showed the greatest variation in both groups was distal to the upper canines.

Conclusions

In the present study, extractive orthodontic treatment appeared to predispose patients to a greater degree of root resorption. Indeed, the bone at the extraction site showed greater resorption in the study group with respect to the control group, and the appearance of intraosseous defects was noted in the former.

Association analysis of clinical aspects and vitamin D receptor gene polymorphism with external apical root resorption in orthodontic patients

INTRODUCTION

Vitamin D is responsible for the regulation of certain genes at the transcription level, via interaction with the vitamin D receptor, and influences host immune responses and aspects of bone development, growth, and homeostasis. Our aim was to investigate the association of TaqI vitamin D receptor gene polymorphism with external apical root resorption during orthodontic treatment.

METHODS

Our subjects were 377 patients with Class II Division 1 malocclusion, divided into 3 groups: (1) 160 with external apical root resorption ≤1.43 mm, (2) 179 with external apical root resorption >1.43 mm), and (3) 38 untreated subjects. External apical root resorption of the maxillary incisors was evaluated on periapical radiographs taken before and after 6 months of treatment. After DNA collection and purification, vitamin D receptor TaqI polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphism. Univariate and multivariate analyses were performed to verify the association of clinical and genetic variables with external apical root resorption (P <0.05).

RESULTS

There was a higher proportion of external apical root resorption in orthodontically treated patients compared with the untreated subjects. In patients orthodontically treated, age higher than 14 years old, initial size of the maxillary incisor root superior to 30 mm, and premolar extraction were associated with increased external apical root resorption. Genotypes containing the C allele were weakly associated with protection against external apical root resorption (CC + CT × TT [odds ratio, 0.29; 95% confidence interval, 0.07-1.23; P = 0.091]) when treated orthodontic patients were compared to untreated individuals.

CONCLUSIONS

Clinical factors and vitamin D receptor TaqI polymorphism were associated with external apical root resorption in orthodontic patients.

Apical root resorption in maxillary incisors when employing micro-implant and J-hook headgear anchorage: a 4-month radiographic study

This study evaluated, over a 4-month study period, the amount of apical root resorption occurring in maxillary central incisors following their retraction when employing either micro-implant or J-hook headgear anchorage. The prospective randomised clinical trial was conducted in Orthodontic Clinic, College of Stomatology, China from 2008-2009. Subjects are patients requiring fixed appliances on waiting list (n=20). In female Han Chinese patients aged from 16-26 years, standardized periapical radiographs from 10 randomly assigned patients with maxillary protrusions comprising the micro-implant group, and from 10 similar patients comprising the J-hook headgear group, were assessed for maxillary central incisor apical root resorption. Measurements before and after orthodontic therapy were also obtained from lateral cephalometric radiographs to calculate incisor horizontal retraction and vertical intrusion distances. Estimated retraction force vectors were calculated in horizontal and vertical directions for both treatment groups. Data analysis employed t-tests and the Pearson correlation test, with α=0.05 for statistical significance. The results showed that when compared with the J-hook group, significantly more apical root resorption shortening of the maxillary central incisors was observed in the micro-implant group (1.27 mm difference, 95% CI=0.70-1.84, P<0.001), which was associated with a significantly larger retraction distance (P=0.004) and a smaller vertical force component (P<0.0001). We are led to conclude that continuous activation of the nickel-titanium coil springs used in the micro-implant group resulted in significantly more apical root resorption shortening and maxillary central incisor retraction than when intermittent J-hook retraction was employed. The employment of continuous duration orthodontic forces presents a risk for increased apical root resorption that requires careful radiographic monitoring.

External apical root resorption in maxillary incisors in orthodontic patients: associated factors and radiographic evaluation

Purpose

This study was performed to evaluate the incidence and degree of external apical root resorption of maxillary incisors after orthodontic treatment and to evaluate particular associated factors related to external apical root resorption.

Materials and Methods

The records and maxillary incisor periapical radiographs of 181 patients were investigated. Crown and root lengths were measured and compared on the pre- and post-treatment periapical radiographs. Crown length was measured from the center of the incisal edge to the midpoint of the cemento-enamel junction (CEJ). Root length was measured from the CEJ midpoint to the root apex. A correction factor for the enlargement difference was used to calculate root resorption.

Results

The periapical radiographs of 564 teeth showed that the average root resorption was 1.39±1.27 (8.24±7.22%) and 1.69±1.14 mm (10.16±6.78%) for the maxillary central and lateral incisors, respectively. The results showed that the dilacerated or pointed roots, maxillary premolar extraction cases, and treatment duration were highly significant factors for root resorption (p<0.001). Allergic condition was a significant factor at p<0.01. Age at the start of treatment, large overjet, and history of facial trauma were also factors significantly associated with root resorption (p<0.05). There was no statistically significant difference in root resorption among the factors of gender, overbite, tongue-thrusting habit, types of malocclusion, and types of bracket.

Conclusion

These results suggested that orthodontic treatment should be carefully performed in pre-treatment extraction patients who have pointed or dilacerated roots and need long treatment duration.

Apical root resorption of incisors after orthodontic treatment of impacted maxillary canines: a radiographic study

INTRODUCTION

The purpose of the study was to evaluate impacted maxillary canines as risk factor for orthodontic apical root resorption.

METHODS

The sample comprised 66 patients treated with fixed appliances. Thirty-two patients with a unilateral impacted maxillary canine, which was distanced from the roots of the incisors at a preliminary phase of treatment before bonding, formed the impaction group, and 34 patients without impactions served as the controls. Root shortening was calculated by using pretreatment and posttreatment intraoral radiographs. Inclination of the eruption path of the impacted canine relative to the midline, axis of the lateral incisor, and nasal line, root development, and the medial and vertical positions of the impacted tooth were recorded on orthopantomograms and lateral cephalometric films. The follicle/tooth ratio was evaluated by using periapical radiographs.

RESULTS

No significant difference in apical resorption of the maxillary incisors was detected between the impaction and control groups, or between the incisors of the impacted and contralateral sides in the same subject. Likewise, no difference in the severity of root resorption was found between the incisors of impacted side alone and the incisors of the control group. Mesial and vertical inclinations of the impacted canines were negatively related to a lateral incisor's root resorption. No correlations were found between resorption and medial or vertical position of the crown of the canine. The follicle/tooth ratio was significantly related to the mesial inclination of the impacted canine, but not to root resorption.

CONCLUSIONS

An impacted maxillary canine, after being distanced from the incisor roots, does not seem to be a risk factor for apical root resorption during orthodontic treatment.

Severe external apical root resorption--local cause or genetic predisposition?

BACKGROUND

Current data suggest that a large extent of the variation in orthodontic root resorption may be explained by differences in individual genetic predisposition. This would imply, however, a similar root resorption reaction in all teeth.

OBJECTIVE

To determine the incidence and extent of severe external apical root resorptions (SEARR) in maxillary incisors during multibracket (MB) appliance treatment.

PATIENTS AND METHODS

Of the whole sample of patients having completed MB treatment at the University of Giessen between 1991 and 2010 (P(Total)=3198), all subjects exhibiting severe root resorptions on at least one maxillary incisor were selected. SEARR were defined according to Malmgren et al. [39] (grade-IV RR=resorption >1/3 root length). Evaluation was performed using orthopantomograms from before and after MB treatment. The crown and root length of the affected teeth were measured. The extent of SEARR was assessed taking pretreatment crown length into consideration.

RESULTS

SEARR was detected in 16 patients. Thus, the incidence of SEARR on maxillary incisors during MB treatment totalled 0.5%. The median of SEARR of the affected incisors was 38.6% of the initial root length (minimum=33.4%, maximum=61.0%). Most subjects exhibited only single affected teeth. Only two subjects (0.06% absolute/12.5% relative) presented four maxillary incisors with SEARR.

CONCLUSIONS

The incidence of SEARR on maxillary incisors during MB treatment (0.5%) was very low compared to the literature. With only 12.5% of SEARR patients presenting four affected teeth, local rather than systemic/genetic factors seem to have predisposed the present subjects to SEARR.

Root shortening in patients treated with two-step and en masse space closure procedures with sliding mechanics

OBJECTIVE

To investigate the comparative amount of root shortening between two-step and en masse space closure procedures.

MATERIALS AND METHODS

Fifty-two patients were selected from a pool of patients satisfying the following inclusion criteria: no evidence of resorption on the pretreatment panoramic radiographs; no dental trauma; no dilacerations of incisor roots, anodontia, or impacted canines; complete root formation at the start of treatment; intact and caries-free incisors; no endodontically treated incisors; Angle Class I or II malocclusion; extraction of four first premolars; and space closure with moderate anchorage. Patients received treatment with either a two-step or an en masse procedure to close the extraction spaces after alignment and leveling with the same preadjusted appliances. Root shortening of the maxillary and mandibular incisors was evaluated on panoramic radiographs, taken before and after space closure, and measured in millimeters. Distortion of measurements caused by panoramic radiographs was corrected by using special metal rods ligated to brackets. Statistical comparisons of root shortening between space closure procedures were investigated with the two-sample t test.

RESULTS

No difference was found in the amount of root shortening between space closure procedures. The average root shortening of maxillary central and lateral incisors was 0.43 +/- 0.12 mm and 0.58 +/- 0.10 mm, respectively, and that of mandibular central and lateral incisors was 0.23 +/- 0.07 mm and 0.22 +/- 0.06 mm, respectively.

CONCLUSION

No difference should be expected in root resorption between two-step and en masse space closure procedure.

Root Resorption in Relation to Orthodontic Tooth Movement

Root resorption is an undesirable sequela of orthodontic tooth movement. The odontoclasts are responsible for root resorption and the process of hyalinization is known to preceed the orthodontic root resorption. It is found that there are several predisposing factors, therefore an evaluation of these factors should be done by careful examination of personal medical history, severity of malocclusion and dental treatment (if any due to previous history of trauma), anterior crossbite etc. The evaluation becomes an essential factor as it helps the orthodontists in detecting the occurance and severity of the root resorption and thereby plan out the treatment more effectively. Orthodontic tooth movements especially intrusion and other movements like tipping, torque are all known to influence the root resorption, therefore the detection using radiographs and repair of root resorption is of utmost significance as root resorption is a more serious problem from a medicolegal stand point of view. However some studies have shown that the repair process is known to occur after the cessation of orthodontic treatment by the deposition of cementum of cellular type. In the light of orthodontist’s liability of what is basically an unpredictable phenomenon, it is necessary that the speciality define this uncertainity and protect its members against unnecessary and unjustified litigation.

Teamwork in orthodontics: Limiting the risks of root resorption

Orthodontic treatment is not without risk. The risks may be due to patient factors (which may not always be evident before treatment) or may come about because of the treatment itself. While the common types of risk are well documented, less information is available as to how some of the more unusual problems can best be managed when they arise; often the need for teamwork between the patient, orthodontist and general dental practitioner (GDP) are underestimated. This paper presents three patients in whom various root-related problems existed either before orthodontic treatment or which arose during orthodontic treatment; demonstrates how they were managed; and highlights the need for teamwork to ensure a 'least harmful' outcome. All patients were followed up for over a year.