Photobiostimulatory Effect of a Single Dose of Low-Level Laser on Orthodontic Tooth Movement and Pain.

Objective: To assess the effect of low-level laser applied at 3 weeks intervals on orthodontic tooth movement (OTM) and pain using conventional brackets (CB). Materials and Methods: Twenty patients with Angle's class II div 1 (10 males and 10 females; aged 20.25 ± 3.88 years) needing bilateral extractions of maxillary first bicuspids were recruited. Conventional brackets MBT of 0.022 in slot (McLaughlin Bennett Trevisi) prescription braces (Ortho Organizers, Carlsbad, Calif) were bonded. After alignment and levelling phase, cuspid retraction began with nitinol closed coil spring on 19 × 25 stainless steel archwire, wielding 150 gram force. 7.5 J/cm2 energy was applied on 10 points (5 buccal and 5 palatal) on the canine roots on the investigational side using gallium-aluminum-arsenic diode laser (940 nm wavelength, iLase™ Biolase, Irvine, USA) in a continuous mode. Target tissues were irradiated once in three weeks for 9 weeks at a stretch (T0, T1, and T2). Patients were given a feedback form based on the numeric rating scale (NRS) to record the pain intensity for a week. Silicon impressions preceded the coil activation at each visit (T0, T1, T2, and T3), and the casts obtained were scanned with the Planmeca CAD/CAM™ (Helsinki, Finland) scanner. Results: The regimen effectively accelerated (1.55 ± 0.25 mm) tooth movement with a significant reduction in distress on the investigational side as compared to the placebo side (94 ± 0.25 mm) (p < 0.05). Conclusions: This study reveals that the thrice-weekly LLLT application can accelerate OTM and reduce the associated pain.

Rayleigh-half normal distribution for modeling tooth movement data.

Clear aligners provide a recent technique to induce orthodontic tooth movement. In this paper, a new one-parameter model, called, Rayleigh-Half Normal distribution (RHN) is proposed for modeling tooth movement data. Various statistical and reliability properties including moments and its associated measures, mean residual life, survival and hazard functions are derived and studied. Moreover, the model parameter is estimated via the method of moments and maximum likelihood. A simulation study was performed to examine the bias and mean square error of the estimated parameter. Finally, the flexibility of the proposed model is illustrated by utilizing a real dental data. The results showed that it could give a better fit than other well-known models.

The National Dental Practice-Based Research Network Adult Anterior Open Bite Study: Treatment recommendations and their association with patient and practitioner characteristics.

INTRODUCTION: This aim of this paper is to describe and identify the practitioner and patient characteristics that are associated with treatment recommendations for adult anterior open bite patients across the United States. METHODS: Practitioners and patients were recruited within the framework of the National Dental Practice-Based Research Network. Practitioners were asked about their demographic characteristics and their treatment recommendations for these patients. The practitioners also reported on their patients' dentofacial characteristics and provided initial cephalometric scans and intraoral photographs. Patients were asked about their demographic characteristics, previous orthodontic treatment, and goals for treatment. Four main treatment groups were evaluated: aligners, fixed appliances, temporary anchorage devices (TADs), and orthognathic surgery. Extractions were also investigated. Predictive multivariable models were created comparing various categories of treatment as well as extraction/nonextraction decisions. RESULTS: Ninety-one practitioners (mostly orthodontists) and 347 patients were recruited from October 2015 to December 2016. Increased aligner recommendations were associated with white and Asian patients, the presence of tongue habits, and female practitioners. TADs were recommended more often in academic settings. Recommendations for orthognathic surgery were associated with demographic factors, such as availability of insurance coverage and practitioner race/ethnicity, and dentofacial characteristics, such as anteroposterior discrepancies, more severe open bites, and steeper mandibular plane angles. Extraction recommendations were largely associated with severe crowding and incisor proclination. CONCLUSIONS: Both doctor and patient demographic factors, as well as dentofacial characteristics, were significantly associated with treatment recommendations for adult anterior open bite patients.

A biomechanical case study on the optimal orthodontic force on the maxillary canine tooth based on finite element analysis.

Excessive forces may cause root resorption and insufficient forces would introduce no effect in orthodontics. The objective of this study was to investigate the optimal orthodontic forces on a maxillary canine, using hydrostatic stress and logarithmic strain of the periodontal ligament (PDL) as indicators. Finite element models of a maxillary canine and surrounding tissues were developed. Distal translation/tipping forces, labial translation/tipping forces, and extrusion forces ranging from 0 to 300 g (100 g=0.98 N) were applied to the canine, as well as the force moment around the canine long axis ranging from 0 to 300 g·mm. The stress/strain of the PDL was quantified by nonlinear finite element analysis, and an absolute stress range between 0.47 kPa (capillary pressure) and 12.8 kPa (80% of human systolic blood pressure) was considered to be optimal, whereas an absolute strain exceeding 0.24% (80% of peak strain during canine maximal moving velocity) was considered optimal strain. The stress/strain distributions within the PDL were acquired for various canine movements, and the optimal orthodontic forces were calculated. As a result the optimal tipping forces (40-44 g for distal-direction and 28-32 g for labial-direction) were smaller than the translation forces (130-137 g for distal-direction and 110-124 g for labial-direction). In addition, the optimal forces for labial-direction motion (110-124 g for translation and 28-32 g for tipping) were smaller than those for distal-direction motion (130-137 g for translation and 40-44 g for tipping). Compared with previous results, the force interval was smaller than before and was therefore more conducive to the guidance of clinical treatment. The finite element analysis results provide new insights into orthodontic biomechanics and could help to optimize orthodontic treatment plans.

Coordinating bracket torque and incisor inclination : Part 1: The development of widely applicable equations.

PURPOSE: The objective of this investigation was to develop equations to describe the geometric relations among "targeted incisor inclinations" (tU1, tL1) accommodating different cephalometric norms (Ricketts, Bergen, etc.) with the "expected inclinations" (eU1, eL1), as they can be generated by bracket torque values according to Andrews, Roth, Ricketts, and MBT. METHODS: In its key parts, the present study is a theoretical work in which structural relationships are described using standard mathematical and geometric methodologies. RESULTS: The "targeted norm-inclinations" (tU1, tL1) were calculated relative to a single reference plane (BOP according to Downs), thus, allowing for a direct comparison of different cephalometric values. Referring to the "expected inclinations" (eU1, eL1), it was found that in addition to bracket torque (BT) morphological and structural parameters also have to be taken into account. These are the "torque coordination angle" (TCA) representing the variation in dental morphology and, the correction angles between BOP and the upper (uOP) (α1) or the lower (lOP) occlusal plane (ß1). Moreover, the angles α2 between an upper (uBPP) and ß2 between a lower bracket positioning plane (lBPP) and the occlusal planes (uOP, lOP) have to be considered. As a consequence, suitable equations were developed (eU1(BOP) = 90°â€¯- BT(U1) - TCA(U1) + α1 - α2, and eL1(BOP) = 90°â€¯- BT(L1) - TCA(L1) + ß1 - ß2), allowing the calculation of expected torque-dependent inclinations (eU1, eL1) and representing the prerequisite for a comparison with the cephalometric targeted values (tU1, tL1). CONCLUSIONS: By developing suitable equations, it became possible to name and quantify those parameters that are responsible for incisor inclinations and enable a comparison with targeted cephalometric values.

Efeito da corticotomia e decorticalização na movimentação ortodôntica: estudo em ratos / Corticotomy and Decortication effect on orthodontic tooth movement: study in rats

Este estudo comparou dois protocolos cirúrgicos, corticotomia e corticotomia com decorticalização, em ratos para verificar alteração na movimentação ortodôntica convencional. 60 animais foram divididos aleatoriamente: Grupo controle (GC) - movimentação ortodôntica convencional; Grupo 1 (G1) -movimentação ortodôntica e corticotomia; Grupo 2 (G2) - movimentação ortodôntica com corticotomia e decorticalização. Os animais foram eutanasiados após 7 e 14 dias. No G1 e G2 houve uma maior movimentação ortodôntica comparado aos animais do GC aos 14 dias (p = 0,009 e 0,016) com uma maior área radiográfica interradicular, menor volume ósseo/volume total, menor área final e menor porcentagem de osso. Aos 7 dias os animais do G2 apresentaram menor volume de osso/volume total comparado com GC e aos 14 dias os animais do G2 apresentaram uma menor medida linear da crista óssea comparado com o GC. Os animais do GC aos 14 dias apresentaram uma maior área final comparado aos 7 dias, enquanto o G2 apresentou maior número de células TRAP positivas tanto aos 7 quanto aos 14 dias comparado com o G1. Na análise histológica aos 7 dias houve frequente reabsorção radicular inicial geralmente associada às áreas de hialinização e aos 14 dias, presença do infiltrado inflamatório e com menor ocorrência de áreas hialinas. O padrão de reabsorção radicular iniciado no 7º dia de movimento e consolidado no 14º dia. Concluímos que a corticotomia acelera a movimentação ortodôntica em 14 dias independente da magnitude da injúria cirúrgica (AU)

This study compared two surgical protocols, corticotomy and decorticalization corticotomy, in rats to verify alteration in conventional orthodontic movement. 60 animals were randomly divided: Group 1 (G1) orthodontic movement and corticotomy, and Group 2 (G2) orthodontic movement with corticotomy and decorticalization. The animals were euthanized after 7 and 14 days. In G1 and G2, there was a greater orthodontic movement compared to CG animals at 14 days (p = 0.009 and 0.016) with a higher interradicular radiographic area, lower bone volume / total volume, lower final area and lower percentage of bone. At 7 days the G2 animals presented lower bone volume / total volume compared to CG and at 14 days G2 animals presented a smaller linear measure of bone crest compared to CG. GC animals at 14 days presented a larger final area compared to 7 days, while G2 presented a higher number of TRAP cells positive at 7 and 14 days compared to G1. In the histological analysis at 7 days, there was frequent initial root resorption generally associated with hyalinization areas and at 14 days, presence of inflammatory infiltrate and less occurrence of hyaline areas. The root resorption pattern started on day 7 of movement and was consolidated on the 14th day. We conclude that corticotomy accelerates orthodontic movement in 14 days regardless of the magnitude of the surgical injury(AU)

Differences between active and passive self-ligating brackets for orthodontic treatment : Systematic review and meta-analysis based on randomized clinical trials.

PURPOSE: In orthodontic treatment, the effects of differences in the design between active and passive self-ligating bracket (ASLB and PSLB, respectively) are usually neglected. This study investigated differences in effectiveness and efficiency between ASLBs and PSLBs. METHODS: To identify randomized, controlled clinical trials (RCTs) comparing ASLB with PSLB, the electronic databases Medline, Embase, Cochrane Central Register of Controlled Trials, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and Chinese Medical Journal Database were searched without language or time limits. Relevant available dental journals and reference lists from included studies were manually searched for applicable reports. Meta-analyses were conducted with the Review Manager program. Two independent reviewers performed all search processes; disagreements were discussed with a third reviewer. RESULTS: Eight studies were included in the systematic review, of which six were included in the meta-analysis due to the data consistency. Three had a low risk of bias, four had an unclear risk of bias, and one had a high risk of bias. With regard to alignment efficiency, meta-analysis favors ASLB [mean difference (MD) -10.24 days, 95% confidence interval (CI) -17.68 to -2.80]. However, the same analysis does not favor either design in terms of width change due to treatment for intercanine (MD -0.49 mm, 95% CI -1.10 to 0.13 mm) interfirst premolar (MD -0.07 mm, 95% CI -0.69, 0.56 mm) intersecond premolar (MD -0.58 mm, 95% CI -1.25 to 0.08 mm) and intermolar (MD 0.10 mm, 95% CI -0.82 to 1.02 mm) width. CONCLUSIONS: Based on current clinical evidence from RCTs, ASLB appears to be more efficient for alignment, while neither design shows an advantage for width change. Further research is needed to confirm present results.

The effectiveness of pendulum, K-loop, and distal jet distalization techniques in growing children and its effects on anchor unit: A comparative study.

BACKGROUND: A common strategy to correct Class II malocclusions using a nonextraction protocol in children is to move the maxillary molars distally using molar distalization appliances, which usually derive their anchorage from maxillary premolars, causing mesialization of premolars and protrusion of incisors. OBJECTIVES: To evaluate the skeletal, dental and soft tissue changes produced by three different distalizing appliances, namely, pendulum, K-loop, and distal jet appliances. MATERIALS AND METHODS: Sixty-six children of mean age 14.13 years requiring molar distalization were divided into three groups: Group I (pendulum appliance), Group II (K-loop), and Group III (distal jet). Lateral cephalometric films were taken before and after 5 months of molar distalization and following cephalometric parameters were used to assess the effects of maxillary molar distalization, namely, anteroposterior skeletal (SNA/SNB/ANB), vertical skeletal (face height ratio/Frankfort-mandibular plane [FMA]/angle formed between Maxillary plane & Mandibular plane (MM)), interdental (overjet/overbite), maxillary dentoalveolar, and soft tissue parameters. RESULTS: There was no significant age difference between the three groups. In overall treatment changes among the three groups, the Anteroposterior skeletal changes were not statistically significant, vertically FMA angle increased by 1.79° ± 2.25° and overbite reduced by 2.38 ± 1.83 mm. The maxillary first molars were distalized by an average of 4.70 ± 3.01 mm (Upper 6 [U6] to pterygoid vertical [PTV]). The maxillary central incisor labial tipping increased to an average of 1.61 ± 2.73 mm and cant of upper lip increased by 3.40° ± 5.88° are statistically significant (P < 0.05). CONCLUSION: All three distalization techniques in growing children produced significant effects on anchor unit. There was an increase in FMA angle, significant bite opening, proclination of the maxillary incisors and increase in the cant of the upper lip.

Evaluation of the Influence of Local Administration of Vitamin D on the Rate of Orthodontic Tooth Movement.

Accelerated orthodontic tooth movement is currently the subject of numerous scientific studies that aimed to improve the duration of orthodontic treatment. Several approaches had been performed in order to reduce the period in which a patient is subjected to orthodontic treatment. This are biological, surgical and physical approaches. Aim: This study has two purposes: first to assess the influence of local administration of vitamin D3 on orthodontic tooth movement and second to evaluate if there is any secondary effect of locally administration of vitamin D3 on dental roots. Material and methods: Every dental arch has been divided in two: one control quadrant and one experimental quadrant. The control canine received only conventional orthodontic treatment in comparison with the experimental canine who benefited from the association between orthodontic therapy and intraligamentary administration of vitamin D3. Results: 6 dental arches were studied. The average rate of tooth movement was greater in experimental canines compared to control canines. We recorded an average of 70 % more tooth movement for the experimental teeth compared to control ones. The differences between the two quadrants (control and experimental) are statistically significant. Conclusions: Locally administration of vitamin D3 seemed to increase the rate of orthodontic tooth movement. No root resorption was found three months after the first administration of vitamin D3 evaluated on cone-beam CT exam (cone-beam computed tomography).

Removable plate treatment of anterior forced crossbite: Effectiveness, efficiency, and potential outcome predictors.

OBJECTIVES: In addition to studying the effectiveness and efficiency of removable acrylic plates in correcting anterior forced crossbite, the influence of outcome predictors were evaluated. METHODS: In all, 65 patients met the inclusion criteria of anterior forced crossbite, mixed dentition, removable plate treatment, and complete case documentation. Effectiveness was assessed based on pre- and posttreatment study casts (which were analyzed for successful treatment outcomes defined as ≥ 1 mm of overjet and overbite) and efficiency was assessed based on treatment duration and number of appointments. Potential outcome predictors were also evaluated, including age, gender, dental maturity, Angle Class, number of teeth in crossbite, severity of crossbite, overbite, ANB angle, Wits appraisal, mandibular plane angle, and patient compliance. RESULTS: Successful crossbite correction was achieved in 48 of the 65 patients (74%) within a median of 2.8 months and 2.0 appointments. Plate treatment was discontinued following another median of 11.6 months and 6.5 appointments. Promising outcome predictors are the number of teeth in crossbite (1-2 versus 3-4 teeth = success in 81 versus 42% of cases), dental maturity (early versus late mixed dentition = success in 84 versus 52% of cases), and Angle Class (I versus III = success in 83 versus 61% of cases). CONCLUSION: Removable acrylic plates were found to be moderately effective and efficient in correcting anterior forced crossbite. Children presenting with Angle Class I and crossbites involving not more than two teeth when treatment is started during the period of early mixed dentition had the best prognosis for treatment success.

Surgical adjunctive procedures for accelerating orthodontic treatment.

BACKGROUND: A range of surgical and non-surgical techniques have received increasing attention in recent years in an effort to reduce the duration of a course of orthodontic treatment. Various surgical techniques have been used; however, uncertainty exists in relation to the effectiveness of these procedures and the possible adverse effects related to them. OBJECTIVES: To assess the effects of surgically assisted orthodontics on the duration and outcome of orthodontic treatment. SEARCH METHODS: We searched the following electronic databases: the Cochrane Oral Health Group's Trials Register (to 10 September 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 8), MEDLINE via OVID (1946 to 10 September 2014), EMBASE via OVID (1980 to 10 September 2014), LILACS via BIREME (1980 to 10 September 2014), metaRegister of Controlled Trials (to 10 September 2014), ClinicalTrials.gov (to 10 September 2014), and the World Health Organization (WHO) International Clinical Trials Registry Platform (to 10 September 2014). We checked the reference lists of all trials identified for further studies. There were no restrictions regarding language or date of publication in the electronic searches. SELECTION CRITERIA: Randomised controlled trials (RCTs) evaluating the effect of surgical adjunctive procedures for accelerating tooth movement compared with conventional treatment (no surgical adjunctive procedure). DATA COLLECTION AND ANALYSIS: At least two review authors independently assessed the risk of bias in the trials and extracted data. We used the fixed-effect model and expressed results as mean differences (MD) with 95% confidence intervals (CI). We investigated heterogeneity with reference to both clinical and methodological factors. MAIN RESULTS: We included four RCTs involving a total of 57 participants ranging in age from 11 to 33 years. The interventions evaluated were corticotomies to facilitate orthodontic space closure or alignment of an ectopic maxillary canine, with the effect of repeated surgical procedures assessed in one of these studies. The studies did not report directly on the primary outcome as prespecified in our protocol: duration of orthodontic treatment, number of visits during active treatment (scheduled and unscheduled) and duration of visits. The main outcome assessed within the trials was the rate of tooth movement, with periodontal effects assessed in one trial and pain assessed in one trial. A maximum of just three trials with small sample sizes were available for each comparison and outcome. We assessed all of the studies as being at unclear risk of bias.Tooth movement was found to be slightly quicker with surgically assisted orthodontics in comparison with conventional treatment over periods of one month (MD 0.61 mm; 95% CI 0.49 to 0.72; P value < 0.001) and three months (MD 2.03 mm, 95% CI 1.52 to 2.54; P value < 0.001). Our results and conclusions should be interpreted with caution given the small number of included studies. Information on adverse events was sought; however, no data were reported in the included studies. AUTHORS' CONCLUSIONS: This review found that there is limited research concerning the effectiveness of surgical interventions to accelerate orthodontic treatment, with no studies directly assessing our prespecified primary outcome. The available evidence is of low quality, which indicates that further research is likely to change the estimate of the effect. Based on measured outcomes in the short-term, these procedures do appear to show promise as a means of accelerating tooth movement. It is therefore possible that these procedures may prove useful; however, further prospective research comprising assessment of the entirety of treatment with longer follow-up is required to confirm any possible benefit.

Severe root resorption resulting from orthodontic treatment: prevalence and risk factors.

OBJECTIVE: To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. METHODS: A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. RESULTS: Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. CONCLUSION: This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset.

Reliability of linear and angular dental measurements with the OrthoMechanics Sequential Analyzer.

INTRODUCTION: The aim of this study was to evaluate the reliability of newly developed software in the assessment of orthodontic tooth movement 3 dimensionally. METHODS: The sample consisted of pretreatment and posttreatment computed tomography scans and plaster dental models of 20 orthodontic patients treated with a hyrax palatal expander as a part of their comprehensive orthodontic treatment. Dental-arch measurements, including arch widths, tooth inclinations, and angulation parameters, were measured on the scans using InvivoDental 3D imaging software (version 5.1; Motionview, Hixson, Tenn). The plaster dental models were laser scanned and superimposed, and measurements were obtained digitally using the new software. Agreement between the digital models and the computed tomography measurements was evaluated with intraclass correlation coefficients, paired t tests, and Bland-Altman plots. A P value of ≤0.05 was considered statistically significant. RESULTS: High agreement, a nonsignificant paired t test, and no indication of agreement discrepancies were observed for most of the measured parameters. CONCLUSIONS: The results confirmed that the new software program offers a reliable tool for dental-arch measurements obtained from 3-dimensional laser-scanned models.

Numerical analysis of tooth movement in different plans of transparent tooth correction therapies.

BACKGROUND: The objective of this study was to investigate how treatment strategies in the same treatment affected the canine's initial displacement and the stress in periodontal ligament using three-dimensional finite element analysis. And to find out the way to design an effective treatment plan. METHODS: Based on computed tomography images of the teeth and their supporting tissues, solid models were used to build finite element models. Three treatment plans of three different transparent tooth correction therapies finite element-analyses were operated. RESULTS: The canine's initial displacement and stresses' distribution in periodontal ligament were obtained. CONCLUSIONS: For rotation movement, the canine should rotate along tooth long axis, and not combine with other kinds of tooth movement as possible. For translation movement, the combination of translation and inclination movement is helpful for the treatment.

Temporary anchorage device usage: a survey among Swiss orthodontists.

BACKGROUND: The aim of the survey was to obtain information on the treatment plan preferences, mechanics and characteristics of temporary anchorage device (TAD) application using a single case presented to orthodontists in Switzerland. METHODS: A structured questionnaire to be completed by all study participants with case-specific (treatment plan including mechanics and TAD usage) and general questions (general fixed appliance and TAD usage as well as professional, educational and demographic questions) together with an orthodontic borderline case was utilised. The case was a female adult with dental Class II/2, deep bite and maxillary anterior crowing, who had been treated in childhood with extraction of four premolars and fixed appliance followed by wisdom tooth extraction. RESULTS: The response rate was 24.4% (108 out of 443). The majority (96.3%, 104) proposed comprehensive treatment, while 3.7% (4) planned only alignment of maxillary teeth. 8.3% (9) included a surgical approach in their treatment plan. An additional 0.9% (1) combined the surgical approach with Class II mechanics. 75.1% (81) decided on distalization on the maxilla using TADs, 7.4% (8) planned various types of Class II appliances and 3.7% (4) combined distalization using TADs or headgear with Class II appliances and surgery. Palatal implants were the most popular choice (70.6%, 60), followed by mini-screws (22.4%, 19) and mini-plates on the infrazygomatic crests (7.0%, 6). The preferred site of TAD insertion showed more variation in sagittal than in transversal dimension, and the median size of mini-screws used was 10.0-mm long (interquartile range (IQR) 2.3 mm) and 2.0-mm wide (IQR 0.3 mm). CONCLUSIONS: Distalization against palatal implants and then distalization against mini-screws were the most popular treatment plans. Preferred site for TAD insertion varied depending on type and size but varied more widely in the sagittal than in the transversal dimension.

Class II treatment by extraction of maxillary first molars or Herbst appliance: dentoskeletal and soft tissue effects in comparison.

AIM: To compare dentoskeletal and soft tissue treatment effects of two alternative Class II division 1 treatment modalities (maxillary first permanent molar extraction versus Herbst appliance). METHODS: One-hundred-fifty-four Class II division 1 patients that had either been treated with extractions of the upper first molars and a lightwire multibracket (MB) appliance (n = 79; 38 girls, 41 boys) or non-extraction by means of a Herbst-MB appliance (n = 75; 35 girls, 40 boys). The groups were matched on age and sex. The average age at the start of treatment was 12.7 years for the extraction and for 13.0 years for the Herbst group. Pretreatment (T1) and posttreatment (T2) lateral cephalograms were retrospectively analyzed using a standard cephalometric analysis and the sagittal occlusal analysis according to Pancherz. RESULTS: The SNA decrease was 1.10° (p = 0.001) more pronounced in the extraction group, the SNB angle increased 1.49° more in the Herbst group (p = 0.000). In the extraction group, a decrease in SNB angle (0.49°) was observed. The soft tissue profile convexity (N-Sn-Pog) decreased in both groups, which was 0.78° more (n. s.) pronounced in the Herbst group. The nasolabial angle increased significantly more (+ 2.33°, p = 0.025) in the extraction group. The mechanism of overjet correction in the extraction group was predominantly dental (65% dental and 35% skeletal changes), while in the Herbst group it was predominantly skeletal (58% skeletal and 42% dental changes) in origin. CONCLUSION: Both treatment methods were successful and led to a correction of the Class II division 1 malocclusion. Whereas for upper first molar extraction treatment more dental and maxillary effects can be expected, in case of Herbst treatment skeletal and mandibular effects prevail.

Systematic review on self-ligating vs. conventional brackets: initial pain, number of visits, treatment time.

OBJECTIVE: Meta-analysis of differences between conventional and self-ligating brackets concerning pain during tooth movement, number of patient visits, total treatment duration, and ligation times. MATERIALS AND METHODS: Online search in Medline, Embase, and Central focused on randomized clinical trials and controlled clinical studies published between 1996 and 2012. RESULTS: Four studies on pain met our inclusion criteria, two on the number of appointments, two on overall treatment time but none on ligation times. Pain levels did not differ significantly between patients treated with conventional or self-ligating brackets after 4 h, 24 h, 3 and 7 days. The number of appointments and total treatment times revealed no significant differences between self-ligating and conventional brackets. CONCLUSION: The lack of significant overall effects apparent in this meta-analysis contradicts evidence-based statements on the advantages of self-ligating brackets over conventional ones regarding discomfort during initial orthodontic therapy, number of appointments, and total treatment time. Due to the limited number of studies included, further randomized controlled clinical trials are required to deliver more data and to substantiate evidence-based conclusions on differences between the two bracket types considering orthodontic pain, number of visits, treatment, and ligation times.

Effectiveness of computer-assisted orthodontic treatment technology to achieve predicted outcomes.

OBJECTIVE: To evaluate the effectiveness of computer-assisted orthodontic treatment technology to produce the tooth position prescribed by the virtual treatment plan. MATERIALS AND METHODS: Posttreatment models of 23 patients treated with SureSmile were digitally superimposed on their corresponding virtual treatment plan models utilizing best-fit surface-based registration. Individual tooth-position discrepancies between virtual treatment plan and actual outcome were computed. Discrepancies less than 0.5 mm in mesial-distal, facial-lingual, and vertical dimensions, and less than 2° for crown torque, tip, and rotation were considered clinically ideal. One-sided test of equivalence was performed on each discrepancy measurement, with P < .05 considered statistically significant. RESULTS: Mesial-distal tooth position was clinically ideal for all teeth with the exception of maxillary lateral incisors and second molars. Facial-lingual tooth position was clinically ideal for all teeth except maxillary central incisors, premolars, and molars, and mandibular incisors and second molars. Vertical tooth position was clinically ideal for all teeth except mandibular second molars. For crown torque, tip, and rotation, discrepancy exceeded the limits considered clinically ideal for all teeth except for crown torque on mandibular second premolars and crown tip on mandibular second premolars and first molars. CONCLUSIONS: The effectiveness of computer-assisted orthodontic treatment technology to achieve predicted tooth position varies with tooth type and dimension of movement.

Incidence and impact of previous orthodontic treatment in patients attending orthognathic combined clinics: a survey.

This prospective questionnaire-based study was designed to determine the incidence of patients attending orthognathic combined clinics who have previously had orthodontic treatment, and to assess the impact, if any, this has had on their proposed surgical treatment. Contemporaneous and historical data from consecutive patients at different stages of treatment who were attending clinics at two London hospitals during a three-month period were included. In total 22/56 patients (39%) had previously had orthodontic treatment, and of those, it had had an undesirable effect on the current management of 10 (45%). The effects included a reduced range of dental movements available to orthodontists (8/23, 35%), undesirable extractions (5/23, 22%), and a prolonging of preoperative orthodontics (5/23, 22%). The median age at which previous orthodontic treatment had been started was 13.5 (range 11-26). Nearly a third of patients reported that they had not been advised by their referring practitioner that a combined orthodontic and surgical approach might be required. The study suggests that preliminary assessment should be improved. Patients should be informed about and prevented from undergoing orthodontic treatment that may limit future surgical management, otherwise they may have to face repeated and prolonged orthodontic treatment, unexpected operations, and potential limitations to the outcome of surgical treatment. This could be achieved through the training and education of all practitioners and the development of referral guidelines.