Sample size estimation: an overview with applications to orthodontic clinical trial designs

Comparison Between an Expert Operator an Inexperienced Operator, and Artificial Intelligence Software: A Brief Clinical Study of Cephalometric Diagnostic

INTRODUCTION

Artificial intelligence (AI) is constantly developing in several medical areas and has become useful to assist with treatment planning. Orthodontics and maxillofacial surgery use AI-based technology to identify and select cephalometric points for diagnostics. Although some studies have shown promising results from the use of AI, the evidence is still limited. Hence, additional investigation is justified.

MATERIALS AND METHODS

In this retrospective study, 2 human operators (1 expert and 1 inexperienced) and 1 software analyzed 30 lateral cephalograms of individuals with orthodontic treatment indications. They measured 10 cephalometric variables and then 2 weeks later, repeated measurements on 30% of the sample. We evaluated the reliability of the measurements between the 2-time points and the differences in the means between the expert operator and the AI software and between the expert and inexperienced operators.

RESULTS

There was high reliability for the expert operator and AI measurements, and moderate reliability for the inexperienced operator measurements. There were some significant differences in the means produced by the AI software and the inexperienced operator compared with the expert operator.

CONCLUSION

Although AI is useful for cephalometric analysis, it should be used with caution because there are differences compared with analysis by humans.

Comparative in-vivo bond failure rate of orthodontic brackets when bracket base is treated with micro-abrasive blasting vs. acid etching: eighteen month randomized control trial and scanning electron microscope study

Background

The aim of this study was threefold. Firstly, it aimed to introduce and detail a novel method for chemically etching the bases of stainless-steel orthodontic brackets. Secondly, the study sought to investigate the structural alterations within the brackets' microstructure following chemical etching compared to those with sandblasted bases, using electron microscopy analysis. Lastly, the study aimed to evaluate and compare the long-term durability and survivability of orthodontic brackets with chemically etched bases versus those with sandblasted bases, both bonded using the conventional acid etch technique with Transbond XT adhesive, over an 18-month follow-up period.

Methods

The study was a randomized clinical control trial with triple blinding and split-mouth study design and consisted of two groups. The brackets in the sandblasted group were prepared by sandblasting the intaglio surface of the base of the bracket with 50 µm SiO2 particles. Hydrofluoric acid was used to roughen the base in the acid-etched group. The bases of the brackets were viewed under an electron microscope to analyze the topographical changes.

Results

A total of 5,803 brackets (3,006 acid-etch, 2,797 sandblasted) in 310 patients were bonded, in a split-mouth design by the same operator. The patients were followed for 18 months. The failure rate of 2.59% and 2.7% was noted in an acid-etched and sandblasted group, respectively. There was a close approximation of curves in the Kaplan-Meier plot, and the survival distribution of the two groups in the log-rank (Mantel-Cox) test was insignificant; x2 = 0.062 (P value = 0.804).

Conclusion

Acid etching if the bases of the brackets can be used as an alternative to sandblasting furthermore acid etching can be performed on the chair side.

Cone-beam computed tomography study of mandibular morphology and tooth compensation in asymmetrical patients

INTRODUCTION

This study evaluated mandibular morphology and transverse dental compensation between symmetrical and asymmetrical subjects, allocated according to sagittal skeletal patterns. In addition, the hypothesis that mandibular morphology and dental compensations differed between symmetrical/asymmetrical groups and also among the different types of sagittal skeletal patterns was tested.

METHODS

Cone-beam computed tomography images of 96 patients were included in this study and were divided into 2 groups according to the degree of menton deviation: a symmetrical group with deviation up to 2.0 mm (n = 48; mean age, 15 ± 6 years), and an asymmetrical group with deviation from 3.5 mm (n = 48; mean age, 16 ± 8 years). The 2 groups were divided in accordance with the ANB angle: Class I, II, and III. Skeletal and dental measurements were performed. Intergroup and intragroup analyses were carried out, using a 2-way analysis of variance to assess the interaction of factors: symmetry and sagittal skeletal pattern; and the Student t test for differences between deviated (Dv) and nondeviated (NDv) sides.

RESULTS

Symmetrical/asymmetrical groups and Class I, II, and III groups were similar in relation to demographic aspects (P = 0.412 and P = 0.357 for sex and age, respectively). Asymmetrical patients had higher values for body length and mandibular ramus and condyle height on the NDv side (P = 0.011, P = 0.024, and P = 0.001, respectively). When comparing the different skeletal patterns, patients with a Class III relationship demonstrated higher values for mandibular ramus height. Intergroup analysis showed no differences in dental parameters. In the comparison between the sides, the asymmetrical group showed a significant difference in canine inclination (P = 0.008), mandibular ramus height (P = 0.004), condyle height (P = 0.010) and gonion to midsagittal plane distance (P = 0.018).

CONCLUSIONS

Asymmetrical subjects showed higher values for canine inclination and mandibular body, ramus and condylar height on the NDv side. The hypothesis was partially confirmed that mandibular morphology and dental compensations are different between symmetrical/asymmetrical groups and among different sagittal skeletal patterns.

Relapse in class II orthognathic surgery: a systematic review

OBJECTIVES

Relapse after orthognathic surgery seems to depend on diverse factors. Proffit et al. postulated in 2007 a "hierarchy of stability" (Head Face Med 6:66, 2007), ranking posttreatment stability after various orthognathic procedures, but no systematically reviewed evidence was provided. Therefore, the aim of this review was to investigate the extent of class II relapse in orthognathic surgery of Angle class II patients depending on the surgical procedure used.

MATERIALS AND METHODS

Seven databases were searched for randomized and controlled clinical trials to compare relapse in surgical procedures for Angle class II patients. After duplicate study selection, data extraction and risk of bias assessment were performed with the ROBINS-I tool as well as data synthesis by frequency distribution, followed by assessment of the quality of evidence with GRADE.

RESULTS

Four non-randomized cohort-studies with a total of 132 patients were included. Bimaxillary procedures as well mandibular advancement procedures proved to be highly stable. Single jaw interventions at the maxilla achieved mostly stable results at sagittal dimension and problematic stability in the vertical dimension. However, there were only limited data available with low quality of evidence.

CONCLUSIONS

Limited existing evidence of low quality partly support the postulated hierarchy of stability of Proffit et al. (Head Face Med 6:66, 2007) and indicates that a surgical correction of class II dysgnathia with bimaxillary procedures and mandibular advancement seems to be highly stable. However, additional studies are needed to address the relation between relapse and surgical orthognathic intervention. Trial registration PROSPERO 2019 CRD42019144873.

Impact of orthodontic brackets on intraoral and extraoral scans

INTRODUCTION

The purpose of this study was to evaluate whether the presence of orthodontic brackets influences the accuracy of digital models generated by intraoral and extraoral scanning from the same patients.

METHODS

Eighteen orthodontic patients in permanent dentition underwent full-arch intraoral scanning with a CEREC Omnicam scanner (Dentsply Sirona, York, Pa). Alginate impressions from each patient's arch were taken, and plaster models were made and scanned. Intermolar, intercanine, and mesiodistal width of the incisors were measured on 2 digital and 1 plaster models. Analysis of variance or Friedman's test was used, with differences between pairs verified by the Bonferroni test or Wilcoxon test, respectively. Both digital models were superimposed using surface-based registration.

RESULTS

Lin's lowest coefficient of agreement was 0.960 (95% confidence interval, 0.900-0.984), which was clinically adequate. No statistically significant differences between the 3 types of model measurements were observed, except for the mandibular left lateral incisor in which scanned intraoral digital models presented Δmedium of 0.05 mm, which was higher than the plaster model. The superimposition of the extraoral and intraoral digital models revealed a minimum difference between models with a mean of means of 0.12 ± 0.03 mm.

CONCLUSIONS

Brackets bonded to teeth affected intraoral scanning; however, the intraoral digital models are clinically comparable and present fewer distortions than plaster models. Moreover, measurements on intraoral and extraoral digital models are excellent in terms of trueness and precision and can be used clinically and in plaster models.

Comparison Between Removable and Fixed Devices for Nonskeletal Anterior Crossbite Correction in Children and Adolescents: A Systematic Review

OBJECTIVE

To compare removable and fixed orthodontic devices in the correction of non-skeletal anterior crossbite in children and adolescents in the mixed dentition.

MATERIALS AND METHODS

Electronic searches were conducted in the following databases: PubMed, Web of Science, Scopus, Medline Ovid, Lilacs, US Clinical Trials, and Proquest. A hand search of the reference lists of the included articles and a Google Scholar search were also conducted. References were evaluated by 2 review authors. Articles that met the eligibility criteria were included. Data extraction, methodological quality assessment (Cochrane tool), and strength of the evidence evaluation (GRADE) were also carried out.

RESULTS

Seven articles were included. The results showed that removable and fixed devices were equally efficacious for overjet correction. Removable and fixed devices can also present inconveniences regarding pain and discomfort levels, the accomplishment of everyday activities (leisure and school), and the performance of functions, such as chewing and speech. However, treatment time and costs were significantly lower in orthodontic therapy with fixed appliances. Sequence generation, allocation concealment, and complete outcome data were not a concern. Blinding of participants or personnel was not reported in any article, and blinding of the assessor was a concern in 2 articles. Selective reporting was a concern in 2 articles. The certainty of the evidence for overjet correction was very low.

CONCLUSION

Removable and fixed orthodontic devices are efficacious for overjet correction in non-skeletal anterior crossbite. However, treatment time and costs are lower for cases treated with fixed devices.

Effects of the cervical headgear in growing Angle Class II malocclusion patients: a prospective study

Objective:

Evaluate dental and skeletal changes resulting from the exclusive use of the cervical headgear for 15 ± 4 months in the treatment of patients with Class II division 1 malocclusion.

Methods:

Differences between the beginning (T₁) and immediately after the end of the therapy (T₂) with the cervical headgear in growing patients (Experimental Group, EG, n = 23) were examined and compared, during compatible periods, with those presented by a group of untreated individuals (Control Group, CG, n =22) with similar malocclusions and chronological age. The cephalometric variables evaluated were: ANB, GoGn.SN, AO-BO, S'-ANS, S'-A, S'-B, S'-Pog and S'-U6 (maxillary first molar). The Shapiro-Wilk and Levene tests were used to evaluate the results.

Results:

Significant differences were found relative to the ANB, S'-U6, AO-BO, S'-ANS, S'-A, S'-B and S'-Pog variables between T₁ and T₂ when comparing both groups. No statistically significant variation was found regarding the GoGn.SN angle.

Conclusions:

The use of cervical headgear promoted distal movement of the maxillary first molars and restricted the anterior displacement of the maxilla, without significantly affecting the GoGn.SN angle.

Lower fixed retainers: bonded on all teeth or only on canines? A systematic review

OBJECTIVE

To evaluate the stability after orthodontic treatment between two types of lower fixed retainers: those bonded onto all anterior teeth or those bonded only onto the canines.

MATERIALS AND METHODS

The following electronic databases were consulted: PubMed, Scopus, Web of Science, Cochrane Library, Lilacs, OpenGrey, ClinicalTrials, and Google Scholar. No restriction of language or year were applied. After selection of studies, risk-of-bias evaluation and qualitative synthesis of the included studies were performed using The Cochrane Collaboration's tool for randomized studies and the "Risk of Bias in Non-randomized Studies of Interventions" (ROBINS-I) tool for nonrandomized studies, and a summary of the overall strength of evidence was presented using the "Grading of recommendations, assessment, development and evaluation" tool.

RESULTS

Among the 180 studies retrieved from the searches, five were included in this review. Three of them showed a low risk of bias, while two presented a high risk of bias. With regard to stability, two studies reported better stability for retainers bonded to all six teeth, while the other three showed no difference. The retainer bonded to all teeth presented a higher breakage rate in one study.

CONCLUSIONS

Stability seems better with lower fixed retainers bonded on all anterior teeth. The breakage rate may not change according to the bonding. However, studies with greater methodological soundness are necessary to reach a more reliable conclusion.

A single-centre investigator-blinded randomised parallel group clinical trial to investigate the effect of probiotic strains Streptococcus salivarius M18 and Lactobacillus acidophilus on gingival health of paediatric patients undergoing treatment with fixed orthodontic appliances: study protocol

BACKGROUND

There is limited data on the beneficial effects of probiotics on the gingival health of patients undergoing treatment with fixed orthodontic appliances. This study aims to compare the effect of probiotic tablets combined with regular oral hygiene versus regular oral hygiene alone on gingival status in these patients. The effect of probiotic intake on plaque formation and salivary microbiome composition will be also assessed.

METHODS AND ANALYSIS

This is a 3 month single-centre, single blind (clinical and laboratory examiners), parallel group randomised controlled two arm superiority trial. Fifty paediatric patients attending the Postgraduate Orthodontic Clinic at the Hamdan Bin Mohammed College of Dental Medicine (HBMCDM), Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU), Dubai, United Arab Emirates, who meet the eligibility criteria will be recruited. Block randomisation with 1:1 allocation and concealment of allocation will be carried out. The treatment group will receive probiotic tablets containing Streptococcus salivarius M18 and Lactobacillus acidophilus together with regular oral hygiene versus the control group on regular oral hygiene alone. Clinical examination and collection of saliva for microbiome assay will be carried out at baseline and end of study. Self-reporting by patients will be used to document acceptability and adverse effects. Statistically significant decrease in gingival bleeding on probing in the treatment group will be classified as primary outcome of treatment success. Statistically significant reduction in Plaque Index, Gingival Index and shift in the composition of the oral microbiome in favour of beneficial bacteria are secondary outcomes indicative of efficacy of probiotic intake.

ETHICS AND DISSEMINATION

Ethical approval for the study has been granted by the HBMCDM, MBRU, Institutional Review Board (Reference #: MBRU-IRB-2018-015). Study findings will be disseminated via publication in peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ISRCTN95085398.

Quality control in the orthodontic department of a Tertiary Military Dental Centre: A decade clinical audit

Background

The objective of the study was to analyze the quality control of the treatment within the orthodontic department by determining the workload, type of treatment, and quality of outcome.

Method

Two hundred eighty patients were selected from departmental archives, who underwent orthodontic treatment since January 2010 and assessed using index of complexity, outcome and treatment need. Descriptive statistics was performed by SPSS, version 21 (IBM, USA). Mann-Whitney U test was applied to assess the difference between complexity and improvement grade.

Result

Orthodontic treatment was provided to 56.43% of female and 43.57% male patients with a mean age of 16.91 years. Angle's class I type malocclusion was the highest with 35.71%. Preadjusted edgewise metal appliance with 95% dominated the mechanics. About 12.14% and 3.57% patients got benefited with myofunctional and orthopedic treatment, respectively. Ten percent of patients were treated with orthognathic surgery. The mean duration of treatment was 31.19 months with a range of minimum of 17 months to a maximum of 46 months. Among 87.14% patients treated by faculty, 47.95% had difficult complexity grading and 22.95% had very difficult complexity grading. Residents had provided treatment with 63.88% difficult and 19.44% very difficult grade. Mann-Whitney U test of overall complexity and improvement grade showed Z score of -9.25715 which was highly significant.

Conclusion

The present study concludes that fair quality control is being maintained by the department considering the number of patients, its severity, and excellent outcomes. However, being the premier institute of Indian Armed Forces, regular clinical audit should be conducted to fulfill demand and supply ratio in appropriation.

Regenerative Endodontic Treatment of Bilateral Necrotic Immature Permanent Maxillary Central Incisors with Platelet-rich Plasma versus Blood Clot: A Split Mouth Double-blinded Randomized Controlled Trial

AIM

Clinical and radiographic assessment of the regenerative potential of bilateral immature permanent maxillary central incisors with necrotic pulps using blood clot (BC) and platelet-rich plasma (PRP) scaffolds.

TRIAL DESIGN

This is a split mouth double-blinded parallel randomized controlled clinical trial.

SUBJECTS AND METHODS

Randomization and blinding: the study started with 15 patients with bilateral maxillary immature permanent central incisors with necrotic pulp. The two upper bilateral central incisors were randomly assigned to either the control (BC scaffold) group I or examined (PRP scaffold) group II. Participant: 13 patients aged 8-14 years fulfilled the study requirements. A follow-up was done for 3, 6, 9, and 12 months. Standardized radiographs were collected during the follow-up period, and radiographic changes were measured using Image J software. Primary outcome measured were clinical: pain, mobility, swelling, and sinus/fistula. Radiographic outcome included increased root length and increase in root thickness. Secondary outcomes were clinical: discoloration and sensibility test. Radiographic outcome included an increase in bone density measurements and a decrease in apical diameter. Standardized radiographs were collected during the follow-up period, and radiographic changes were measured using Image J software.

RESULTS

All 26 treated teeth survived during the 12-month follow-up period with 100% success rate. PRP-treated teeth showed a statistically significant increase in radiographic root length, width, periapical bone density, and a decrease in apical diameter when compared with BC. At the end of 12 months, all treated teeth did not respond to the sensibility test. BC displayed a significantly higher amount of crown discoloration compared to the PRP group.

CONCLUSION

For necrotic immature teeth, regenerative endodontic treatment using PRP is a desirable alternative to BC and shows excellent 12-months prognosis.

HOW TO CITE THIS ARTICLE

Rizk HM, AL-Deen MSS, et al. Regenerative Endodontic Treatment of Bilateral Necrotic Immature Permanent Maxillary Central Incisors with Platelet-rich Plasma versus Blood Clot: A Split Mouth Double-blinded Randomized Controlled Trial. Int J Clin Pediatr Dent 2019;12(4):332-339.

Effects of Low-Intensity Pulsed Ultrasound Therapy on the Temporomandibular Joint Complex in Conjunction With a Fixed Functional Appliance: A Prospective 3-Dimensional Cone Beam Computed Tomographic Study

OBJECTIVES

This prospective study aimed to analyze 3-dimensional changes in the temporomandibular joint (TMJ) complex with a synergistic effect of functional jaw orthopedics using a fixed functional appliance and low-intensity pulsed ultrasound (LIPUS) therapy.

METHODS

Forty patients with skeletal class II malocclusion were randomly assigned to 4 groups (2 control groups and 2 test groups) of 10 patients each. After insertion of the fixed functional appliance, the test group was stimulated with LIPUS therapy in the TMJ region bilaterally for 20 minutes daily for first 10 days and thereafter at least 3 times per week until complete mandibular advancement was achieved. Three-dimensional images obtained with a cone beam computed tomographic scanner were used to analyze the changes in the TMJ complex at the prefunctional stage and after completion of functional appliance therapy. Direct intragroup and intergroup comparisons for different morphometric variables were conducted with the Student t test.

RESULTS

The 40 patients included 20 male and 20 female patients between the ages of 12 and 16 years (mean age ± SD, 13.2 ± 1.8 years). Both the test groups and the control groups showed statistically significant variable changes in condylar head position and morphometric changes in relation to the joint space analysis (mean differences, -1.000 and -1.080 mm; P < .05). However, no significant differences were found during the intergroup comparisons at the prefunctional and postfunctional stages for the variables examined, except for the measurements of the linear distance of the condyle to the external auditory meatus on both the right and left sides at the prefunctional phase.

CONCLUSIONS

Low-intensity pulsed ultrasound therapy positively affects the quantum of the joint space, thus proving to be a promising adjunct in enhancing treatment outcomes of functional jaw orthopedics in growing patients with skeletal class II malocclusions.

Evaluating the treatment effectiveness and efficiency of Carriere Distalizer: a cephalometric and study model comparison of Class II appliances

Background

The purpose of this study was to evaluate the treatment effectiveness of Carriere Distalizer in comparison to Class II intermaxillary elastics and Forsus.

Methods

Three groups of patients treated with Class II intermaxillary elastics (n = 18), Carriere Distalizer (n = 18), and Forsus appliance (n = 18) were collected from three private orthodontic practices. Inclusion criteria were as follows: (1) 10–14 years old of start age with permanent dentition, (2) no history of previous orthodontic treatment, (3) complete pre- and post-treatment records, (4) dental Class II division 1 (end-to-end or more), (5) no pre-treatment transverse discrepancy, (6) non-extraction treatment plan, and (7) Class I post-treatment occlusal relationship. The data consisted of cephalometric and study model measurements from pre- and post-treatment records and treatment time. Two-tail Student t test was used to analyze the differences in cephalometric changes and dental corrections between Carriere Distalizer group and Class II elastics/Forsus group.

Results

All three groups of patients showed no differences in the age of treatment initiation, pre-treatment cephalometric measurements and discrepancy index (DI). The time of Class II correction for Carriere Distalizer was significantly shorter than that for Class II elastics; there was no difference in the length of Class II correction between Carriere Distalizer and Forsus groups. The amount of Class II correction (canine/molar relationship) was significantly lower for Carriere Distalizer when compared with Forsus appliance. Carriere Distalizer, similarly to Class II elastics, did not induce any statistically significant correction in skeletal component (ANB and Wits appraisal).

Conclusions

There is no clinically significant skeletal correction induced by Carriere Distalizer in growing patients. Carriere Distalizer can be applied to treatment of mild to moderate Class II dental malocclusion over 6 months on average, although the total treatment time may be prolonged due to various side effects. Overall, the Carriere Distalizer appears to be no more effective or efficient than alternatives in the treatment of Class II malocclusion.

Aesthetic perceptions and psychosocial impact of malocclusion: comparison between cleft and non-cleft patients and their parents

Objective

To evaluate the influence of dentofacial attractiveness using the 'Psychosocial Impact of Dental Aesthetics Questionnaire' (PIDAQ), Satisfaction with Life Scale (SWLS) and Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) in patients with cleft lip/palate (CLP), and non-cleft orthodontic patients (Non-CLP) and their parents.

Materials and methods

Eighty patients (aged 11-19 years) comprising 40 CLP and 40 non-CLP were administered the PIDAQ and SWLS questionnaires to be rated individually by the patients, along with IOTN-AC rated by the patients and their parents, respectively. The subjects were also sub-divided according to their age, i.e. pre-adolescent and adolescent.

Results

The PIDAQ subpart scores for aesthetic concern differed between the two groups, with a significantly (P < 0.02) lower scoring for the CLP group. The adolescent CLP group scored more negatively than the pre-adolescent group in the dental self-confidence and social impact sub-parts of PIDAQ. No significant differences were observed for satisfaction with life. The parents' IOTN-AC score for both groups was significant (P < 0.05) greater than the patient's score, especially for adolescent subjects.

Limitations

Non-condition specific questionnaires with restrictive sampling sizing and non-inclusion of parameters like stress coping mechanism etc.

Conclusion

The parents rated the malocclusion of their child more critically than the child itself. A majority of the CLP group had a problem in identifying themselves using the IOTN-AC as no photo existed depicting a Class III or edge-to-edge malocclusion. Attitudes, especially perceptions of the aesthetics of front teeth, are crucial factors influencing patient's psychological self-concept, social confidence, and treatment need in CLP patients and non-CLP patients, having more relevance as the patient matures towards adolescence and adulthood.

Comparative evaluation of treatment outcomes between temporary anchorage devices and Class III elastics in Class III malocclusions

INTRODUCTION

Our objective was to elucidate the differences in treatment outcomes caused by the different mechanics of temporary anchorage devices (TADs) and Class III elastics in patients with Class III malocclusions.

METHODS

Records of 23 patients with Angle Class III malocclusion were selected retrospectively. All had been treated with nonextraction comprehensive orthodontic treatment; 11 were treated with TADs and 12 with Class III elastics. Pretreatment and posttreatment lateral cephalograms were used for evaluation of the treatment outcomes. A paired t test and a Student t test were used for statistical analysis.

RESULTS

In both groups, proper overjet and Class I molar relationships were achieved, and the occlusal plane was rotated counterclockwise. In the elastics group, distal tipping of the mandibular molars, extrusion of the mandibular incisors and maxillary molars, clockwise rotation of the mandibular plane angle, and increased ANB angle were observed. In the TADs group, distal tipping and intrusion of the mandibular molars, bodily movement of the mandibular incisors, and reduced mandibular plane angle were observed.

CONCLUSIONS

In nonextraction treatment for Class III malocclusions, the mandibular plane angle was increased in the elastics group, whereas it was decreased in TADs group. Thus, we suggest that Class III elastics are preferred for low-angle, short-face patients, whereas TADs are preferred for high-angle, long-face patients.

Characterization and coating stability evaluation of nickel-titanium orthodontic esthetic wires: an in vivo study

The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure) were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p < 0.0001). In average, the most recently launched wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346) when the latest launched wire (13.27%) was compared to the control (29.63%). In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.

Dentoalveolar mandibular changes with self-ligating versus conventional bracket systems: A CBCT and dental cast study

OBJECTIVE:

The aim of the present study was to compare dentoalveolar changes in mandibular arch, regarding transversal measures and buccal bone thickness, in patients undergoing the initial phase of orthodontic treatment with self-ligating or conventional bracket systems.

METHODS:

A sample of 25 patients requiring orthodontic treatment was assessed based on the bracket type. Group 1 comprised 13 patients bonded with 0.022-in self-ligating brackets (SLB). Group 2 included 12 patients bonded with 0.022-in conventional brackets (CLB). Cone-beam computed tomography (CBCT) scans and a 3D program (Dolphin) assessed changes in transversal width of buccal bone (TWBB) and buccal bone thickness (BBT) before (T₁) and 7 months after treatment onset (T₂). Measurements on dental casts were performed using a digital caliper. Differences between and within groups were analyzed by Student's t-test; Pearson correlation coefficient was also calculated.

RESULTS:

Significant mandibular expansion was observed for both groups; however, no significant differences were found between groups. There was significant decrease in mandibular buccal bone thickness and transversal width of buccal bone in both groups. There was no significant correlation between buccal bone thickness and dental arch expansion.

CONCLUSIONS:

There were no significant differences between self-ligating brackets and conventional brackets systems regarding mandibular arch expansion and changes in buccal bone thickness or transversal width of buccal bone.

Efficacy of a new sealant to prevent white spot lesions during fixed orthodontic treatment : A 12-month, single-center, randomized controlled clinical trial

BACKGROUND AND OBJECTIVE

White spot lesions (WSLs) are an undesirable side effect of fixed orthodontic appliance therapy and are reported to occur in 2-96 % of orthodontic patients. In this study, the efficacy of a new sealant to prevent WSLs during fixed orthodontic treatment was compared to a control group that did not receive sealant.

PATIENTS AND METHODS

For this 2-arm parallel-group randomized trial, 50 subjects aged 12-18 years (mean age 14.57 ± 2.04 years) were recruited from the orthodontics department at Mansoura University, Egypt. Eligibility criteria were no restorations, no active WSLs or caries, and adequate oral hygiene. Subjects were randomized in a 1:1 ratio to one of the two arms prior to undergoing fixed orthodontic treatment, namely a single application of SeLECT Defense™ sealant during the bracketing appointment or no sealant (control arm). Instructions and dentifrices for local home fluoridation regimen were identical in both groups. Oral hygiene was assessed using the Approximal Plaque Index (API) at specified time intervals. Dental photographs were taken for blinded WSLs assessment; inter- and intra-operator error were also calculated. Categorical data were tested using the χ ² test, and a logistic regression model was adopted to detect associations between decalcification (WSLs), sealant application, and oral hygiene status.

RESULTS

Only excellent or good oral hygiene were independent prognostic factors for preventing severe WSLs (p = 0.035). No significant effect on caries incidence was observed for the sealant.

CONCLUSIONS

In combination with adequate oral hygiene SeLECT Defense™ helps to reduced the frequency of WSLs. However, the sealat showed no significant effect as sole preventive strategy.

How sample size influences research outcomes

Sample size calculation is part of the early stages of conducting an epidemiological, clinical or lab study. In preparing a scientific paper, there are ethical and methodological indications for its use. Two investigations conducted with the same methodology and achieving equivalent results, but different only in terms of sample size, may point the researcher in different directions when it comes to making clinical decisions. Therefore, ideally, samples should not be small and, contrary to what one might think, should not be excessive. The aim of this paper is to discuss in clinical language the main implications of the sample size when interpreting a study.

The CONSORT Statement: Application within and adaptations for orthodontic trials

High-quality randomized controlled trials (RCTs) are an integral part of evidence-based medicine. RCTs are the bricks and mortar of high-quality systematic reviews, which are important determinants of health care policy and clinical practice. For published research to be used most effectively, investigators and authors should follow the guidelines for accurate and transparent reporting of RCTs. The consolidated standards of reporting trials (CONSORT) statement and its extensions are among the most widely used reporting guidelines in biomedical research. CONSORT was adopted by the American Journal of Orthodontics and Dentofacial Orthopedics in 2004. Since 2011, this Journal has been actively implementing compliance with the CONSORT reporting guidelines. The objective of this explanatory article is to highlight the relevance and implications of the various CONSORT items to help authors to achieve CONSORT compliance in their research submissions of RCTs to this and other orthodontic journals.

Sample size calculation in metabolic phenotyping studies

The number of samples needed to identify significant effects is a key question in biomedical studies, with consequences on experimental designs, costs and potential discoveries. In metabolic phenotyping studies, sample size determination remains a complex step. This is due particularly to the multiple hypothesis-testing framework and the top-down hypothesis-free approach, with no a priori known metabolic target. Until now, there was no standard procedure available to address this purpose. In this review, we discuss sample size estimation procedures for metabolic phenotyping studies. We release an automated implementation of the Data-driven Sample size Determination (DSD) algorithm for MATLAB and GNU Octave. Original research concerning DSD was published elsewhere. DSD allows the determination of an optimized sample size in metabolic phenotyping studies. The procedure uses analytical data only from a small pilot cohort to generate an expanded data set. The statistical recoupling of variables procedure is used to identify metabolic variables, and their intensity distributions are estimated by Kernel smoothing or log-normal density fitting. Statistically significant metabolic variations are evaluated using the Benjamini-Yekutieli correction and processed for data sets of various sizes. Optimal sample size determination is achieved in a context of biomarker discovery (at least one statistically significant variation) or metabolic exploration (a maximum of statistically significant variations). DSD toolbox is encoded in MATLAB R2008A (Mathworks, Natick, MA) for Kernel and log-normal estimates, and in GNU Octave for log-normal estimates (Kernel density estimates are not robust enough in GNU octave). It is available at http://www.prabi.fr/redmine/projects/dsd/repository, with a tutorial at http://www.prabi.fr/redmine/projects/dsd/wiki.

Do we need primer for orthodontic bonding? A randomized controlled trial

OBJECTIVE

To evaluate the clinical performance of APC™II Victory Series™ (3M Unitek) brackets in direct orthodontic bonding with and without the use of primer.

DESIGN

A single-operator, two-centre prospective, non-inferiority randomized controlled clinical trial.

SETTING

The Orthodontic departments at the Leeds Dental Institute and St Luke's Hospital, Bradford, UK.

ETHICAL APPROVAL

Ethical approval was granted by Leeds (East) Research Ethics Committee on 18th of December 2009 (Reference 09/H1306/102).

PROTOCOL

The protocol was not published prior to trial commencement.

SUBJECTS AND METHODS

Ninety-two patients requiring orthodontic treatment with fixed appliances were randomly allocated to the control (bonded with primer) or test groups (bonded without primer). Patients were randomly allocated to either the control or experimental group. This was performed by preparing opaque numbered sealed envelopes in advance using a random numbers table generated by a computer by an independent third party . Once the envelopes were opened, blinding of the operator and the patient was no longer possible due to the nature of the intervention. Patients were approached for inclusion in the trial if they qualified for NHS orthodontic treatment requiring fixed appliances and had no previous orthodontic treatment.

MAIN OUTCOME MEASURES

Number of bracket failures, time to bond-up appliances, and the adhesive remnant index (ARI) when bracket failure occurred, over a 12-month period

RESULTS

Failure rate with primer was 11.1 per cent and without primer was 15.8 per cent. Bonding without primer was shown statistically to be non-inferior to bonding with primer odds ratio 0.95-2.25 (P = 0.08). Mean difference in bond-up time per bracket was 0.068 minutes (4 seconds), which was not statistically significant (P = 0.402). There was a statistically significant difference in the Adhesive Remnant Index - ARI 0 with primer 49.4 per cent, no primer 76.5 per cent, (P < 0.0001).

LIMITATIONS

As the study was only performed by one operator, the results can therefore only be truly be applied to their practice. Also this study was powered to ascertain if there was no difference between the 2 groups up to 5%, however orthodontists may consider a change in the bracket failure rate of 2% to be clinically significant.

CONCLUSION

When bonding with APC™II Victory Series™ brackets without primer was shown statistically to be non-inferior to bonding with primer (P =0.08). There was no significant difference in bond-up times. Bond failure was more likely to happen at the composite-enamel interface when bonded without a primer.

CONFLICT OF INTEREST

No conflict of interest for all authors.

FUNDING

No funding sources were used.

REGISTRATION

Study was not registered on external databases.

Effect of intravenous patient controlled ketamine analgesiaon postoperative pain in opium abusers

Background:

Acutepostoperative pain is among the worst experience that patient scan undergo, and many analgesics have been used to suppress it; especially in chronic opium abusers. Ketamine is an N-methyl-D-aspartate antagonist analgesic, having both anesthetic and analgesic properties, which are not affected to the same extent in chronic opium abusers.

Objectives:

In this study, we assessed the analgesic effects of ketamine added to morphine as a patient-controlled analgesia method for acute pain management, compared with a placebo, inchronic maleopium abusers.

Patients and Methods:

After institutional review board approval for ethical considerations, a randomized double-blinded placebo controlled clinical trial was conducted. A total of 140 male patients aged 18-65 years, undergoing orthopedic surgery, were entered into the study after matching inclusion and exclusion criteria. All patients received the same anesthesia method; while the first group received ketamine (1mg/mL) and morphine (0.5 mg/mL) as a patient-controlled analgesia (70 patients), the second group received morphine (0.5 mg/mL) plus normal saline (70 patients). P value less than 0.05 was considered statistically significant.

Results:

The ketamine and morphine group of patients experienced less postoperative pain and required less postoperative rescue analgesia. However, the unwanted postoperative side effects were nearly the same; although increased levels of postoperative nausea and vomiting were observed in the ketamine and morphine group

Conclusions:

This study demonstrated improved analgesic effects after using intravenous patient controlled analgesia with ketamine on postoperative pain in opium abusers.