Effect of Molar Distalization on Condyle-Glenoid Fossa Relationship.

Objective: It is essential to be aware of the potential effects of orthodontic treatment on tissues and anatomical structures associated with the masticatory system, especially the temporomandibular joint (TMJ). Little information is available about the consequences of molar distalization on the TMJ. Therefore, this study is aimed at investigating the changes of the condyle-fossa relationship after molar distalization using the distal jet appliance. Materials and Methods: The sample consisted of twenty-five patients (mean age 20.4 ± 2.6) who underwent molar distalization by the distal jet appliance. CBCT scans were taken before (T0) and after (T1) the completion of the molar distalization. Joint spaces (anterior, superior, and posterior) and cephalometric vertical angles (SN.GOME and Björk sum) were measured and compared at T0 and T1. Results: Superior and posterior joint spaces increased significantly after molar distalization (PS 0.29 mm, P < 0.001, SS 0.06 mm, P < 0.5). Vertical cephalometric angles also increased after molar distalization by the distal jet appliance (SN.GOME 0.92°, Björk 1.11°). Conclusion: There was a statistically significant increase in the superior and posterior joint spaces after molar distalization. However, this increase may not be of clinical importance. The vertical dimension has also increased.

Linear and angular transfer accuracy of labial brackets using three dimensional-printed indirect bonding trays: A systematic review and meta-analysis.

OBJECTIVES: To assess the transfer accuracy of three dimensional-printed trays (3D-printed trays) and to compare the accuracy of this approach with the other methods used for the same purpose. MATERIALS AND METHODS: An electronic search was performed in PubMed, Scopus, Web of science, Google Scholar and ProQuest (dissertation and theses). Studies were eligible for inclusion if they involved the assessment of transfer errors measured by the superimposition of the original set-up of brackets and the final positions after transfer. Risk of bias was assessed using Cochrane's tools. RESULTS: Seven studies were included. The pooled estimate of the transfer error in the linear dimensions showed an error of 0.095mm in the mesiodistal direction (95%CI: 0.035, 0.155), 0.114mm in the buccolingual direction (95%CI: 0.067, 0.160) and 0.111mm in the vertical direction (95%CI: -0.033, 0.255). Concerning the angular dimensions, the pooled estimate showed a tipping error of 1.3420 (95%CI: 0.444, 2.240), rotational error of 0.9980 (95%CI: 0.323, 1.672), and torque error of 1.9130 (95%CI: 0.922, 2.903). Thus, the maximum transfer error was in the bucco-lingual and torque directions. 3D-printed trays had better control in mesiodistal and vertical directions than vacuum-formed trays. Polyvinyl siloxane trays were more accurate in the vertical direction than 3D-printed trays. The scarcity of randomized clinical trials is the main risk of bias of the included studies. CONCLUSIONS: According to the available evidence, 3D-printed trays have an acceptable transfer accuracy, based on the American Board of Orthodontics Objective Grading System (ABO OGS), with maximum linear transfer error in the buccolingual direction and maximum angulation error in the torque. Conducting randomized clinical trials on this topic is highly recommended.

Changes in surface morphology, chemical and mechanical properties of clear aligners during intraoral usage: A systematic review and meta-analysis.

OBJECTIVES: To assess the scientific evidence related to the alterations in surface morphology, chemical and mechanical properties of clear aligners during intraoral usage. MATERIALS AND METHODS: An extensive electronic search, with no restrictions, was performed in six databases. Studies were eligible for inclusion if they involved the comparison of surface morphology, chemical and/or mechanical changes of clear aligners before and after intraoral usage. Methodological shortcomings and the quality of the studies were ranked using the Cochrane's tools (RoB2 and ROBINS-I). RESULTS: Four articles were included in this systematic review. Only studies investigating the changes in Smart Track (LD30) material, used for Invisalign™ products, met the inclusion criteria. Regarding changes in surface morphology and chemical properties, LD30 exhibited distortion of surface serrations and ions exchange during usage. With respect to the mechanical alterations, the pooled estimate, of data from 70 aligners, showed a significant decrease in the indentation modulus (SMD=-2.41; 95% CI(-3.39, -1.43); P<0.001) and Martens hardness (SMD=-3,38; 95% CI(-6.24, -0.52); P=0.02) after usage; reflecting a decrease in both force delivery capacity and wear resistance. The main risk of bias affecting the available studies were the confounding and selection of participant's bias. CONCLUSIONS: Despite Invisalign™ being the aligner system most commonly used, there is a strong need for studies investigating the in-vivo aging of other materials, in order to precisely determine the best material that could serve treatment needs. According to the current evidence, LD30 exhibited changes in surface morphology, chemical, and mechanical properties during usage, which could contribute to the differences between the predicted and final clinical results.

Is there any enhanced treatment effect on class II growing patients when Forsus Fatigue Resistant Device is reinforced by either miniplates or miniscrews? A systematic review and meta-analysis.

OBJECTIVE: To investigate the treatment effects, on skeletal class II growing patients, when miniplate-anchored Forsus Fatigue Resistant Device (MP-FFRD) and miniscrew-anchored Forsus Fatigue Resistant Device (MS-FFRD) were separately compared with conventional Forsus Fatigue Resistant Device (C-FFRD). Thus, distinguishing the differences between direct and indirect anchorages. MATERIALS AND METHODS: Comprehensive electronic and hand searching, without restrictions, were performed in CENTRAL, Scopus, Web of science, EMBASE via OVID, PubMed and ClinicalTrials.gov. Only randomized controlled trials (RCTs) and controlled clinical trials (CCTs) with patients receiving orthodontic functional treatment with MP-FFRD or MS-FFRD were included. Risk of bias was assessed using Cochrane's tools (RoB 2 and ROBINS-I). For quantitative synthesis, inverse variance method and standardized mean differences with 95% confidence intervals were chosen. RESULTS: Four RCTs and three CCTs were included. All reviewed articles included 101 patients in the experimental group and 103 patients in the control group. Regarding MP-FFRD, the analysis included data from 78 subjects (39 MP-FFRD, 39 C-FFRD). The pooled estimates showed an increase in SNB (SMD=0.7; 95% CI (0.21, 1.19); P=0.005) and in mandibular length (Co-Gn) (SMD=1.69; 95% CI (1.11, 2.27); P<0.001) in MP-FFRD compared with C-FFRD. Additionally, a reduction in lower incisors' inclination was observed in MP-FFRD group (SMD=-3.13; 95%CI (-3.83, -2.43); P<0.001). Concerning MS-FFRD, the analysis included data from 94 subjects (46 MS-FFRD, 48 C-FFRD). No significant improvement was achieved in SNB (SMD=0.19; 95% CI (-0.22, 0.60); P=0.36), yet two studies out of three reported a better control in the lower incisors' inclination. CONCLUSIONS: According to the available evidence, the direct loading of FFRD on bilateral miniplates enhanced the skeletal and dental corrections in class II growing patients; however, the clinical significance of the statistical results is questionable. The treatment effects of the indirect loading of FFRD on miniscrews were mainly dentoalveolar, yet with better control of lower incisors' inclination.

Effectiveness of different adjunctive interventions in the management of orthodontically induced white spot lesions: A systematic review of systematic reviews and meta-analyses.

The purposes of this review were to appraise the current evidence on the management of orthodontically induced white spot lesions (OIWSLs) and to choose the best evidence from among conflicting systematic reviews. The published literature was searched from inception through November 2019 in 5 databases. Only systematic reviews and/or meta-analyses were eligible for inclusion. Methodological quality was assessed using A Measurement Tool to Assess Systematic Reviews-2 (AMSTAR-2). The Jadad decision algorithm was applied to choose the best available evidence from among discordant reviews. Thirteen publications were included. The interventions reported in the management of OIWSLs were topical fluorides, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-containing products, fluoridecontaining bonding materials, laser therapy, resin infiltration, and micro-abrasion. The methodological quality of the reviews ranged between moderate and critically low according to the AMSTAR-2 tool. Based on the Jadad decision algorithm criteria, topical fluorides yielded a 25-30% prevention of OIWSLs; however, their effect on reversing OIWSLs was unclear. The CPP-ACP products were effective in both preventing and reversing OIWSLs. No differences were noted between fluoride-releasing adhesives and conventional adhesives. Laser irradiation was effective in preventing OIWSLs, with some concerns about the argon laser at a certain setting. Finally, there is a lack of reliable evidence supporting the efficacy of resin infiltration or micro-abrasion due to the limited number of available studies. Based on the currently available information, topical fluorides and laser irradiation are effective in preventing OIWSLs. The CPP-ACP products are effective in preventing and reversing OIWSLs. Fluoride-releasing adhesives have no effect on OIWSL prevention.

Effectiveness of supplemental vibrational force in reducing pain associated with orthodontic treatment: a systematic review.

OBJECTIVE: The aim of this review was to systematically appraise the current evidence of utilizing vibration to reduce orthodontic pain. METHOD AND MATERIALS: A comprehensive search was performed in ten databases. Only randomized controlled trials (RCTs) with patients receiving orthodontic treatment accompanied by vibrational force application were included. Risk of bias was assessed using the Cochrane tool. The lack of reasonable homogeneity across studies prevented the quantitative synthesis of the data. RESULTS: Fifteen RCTs were included. Three out of four RCTs revealed lower pain levels in at least one time-point when aligners were enhanced by vibration. Three out of 11 RCTs found that vibration accompanying fixed appliances was effective in reducing orthodontic pain. All studies had different methodologic shortcomings including: performance bias due to lack of participants' blinding; inappropriate sample size calculation; nonuniform demographic characteristics of participants; high potential of retrospective documentation of pain perception; and attrition bias. CONCLUSION: It is difficult to answer the question of whether vibration alleviates orthodontic pain or not, especially with the multiple existing shortcomings. More precise research is needed. It is recommended to focus on comparing different vibrational variables in an attempt to find the optimal values that might contribute to pain reduction, including: vibrational frequency; magnitude; and number and duration of sessions per day. Based on the concept of stimulation-induced analgesia, it is suggested that future research highlights the number of vibration sessions/day.

Effectiveness of low-level laser therapy in accelerating the orthodontic tooth movement: A systematic review and meta-analysis.

OBJECTIVES: The aim of the paper was to appraise the current evidence of the effectiveness of low-level laser therapy (LLLT) in accelerating the tooth movement. METHODS: A comprehensive search was performed in 9 databases up to June 2019. Only randomized controlled trials (RCTs) were included. The risk of bias was assessed using the Cochrane Collaboration tool. The quantitative data synthesis was attainable only for the studies evaluating the effect of laser on canine retraction; the qualitative description was used for the rest of the studies. The overall quality of evidence was rated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria. RESULTS: A total of 25 RCTs were included in this review. The radiated upper canines showed a greater retraction ­ 0.50 mm and 0.49 mm at months 2 and 3, respectively. The radiated lower canines showed a greater retraction ­ 0.28 mm and 0.52 mm at months 2 and 3, respectively. No statistically significant differences were observed among the upper and lower canines after the 1st month of retraction. When the GRADE approach was utilized, the overall quality of evidence limited confidence in the estimates. The qualitative description revealed enhanced tooth movement when LLLT was applied. The attrition bias was the main risk factor affecting the methodology of the studies. CONCLUSION: Low-level laser therapy can speed up the rate of the tooth movement. However, the overall quality of evidence ranged from low to very low and the clinical significance of the obtained statistically significant differences is questionable. Hence, more precise studies are needed. As discussed in this review, it is highly recommended to express and compare the laser dosage with the total number of joules applied per month rather than the previously used J/cm2. Moreover, the previous recommendation indicating that lower energy densities (2.5, 5 and 8 J/cm2) are more effective than 20 and 25 J/cm2 is misleading.

Skeletal Age-related Changes of Midpalatal Suture Densities in Skeletal Maxillary Constriction Patients: CBCT Study.

AIM: To determine if density measurements of the midpalatal suture and cervical vertebral maturation index (CVMI) are related, and to investigate if CVMI could help in predicting of the developmental status of the midpalatal suture. MATERIALS AND METHODS: Cone-beam computed tomography (CBCT) images of 95 skeletal maxillary constriction patients (aged 8 to 18 years) were examined. The maturational stages of the cervical vertebrae were visually defined, and midpalatal suture density in the anterior region, the middle region, and the posterior region were measured. One-way ANOVA and Fisher's least significant difference (LSD) post-hoc test were used for statistical assessment. RESULTS: Significant differences were found in MPDS: in anterior region between (c1,c2,c3,c4) and (c5,c6) stages, in middle region between (c1,c2,c3) and (c5,c6) stages, and in posterior region between (c1,c2,c3) and (c4,c5,c6) stages. CONCLUSION: Midpalatal suture densities in all regions increase with skeletal maturation advancement.The significant increase after puberty may have the key role in decreasing the skeletal effects of RME after that age. Clinical significances: It is important to assess the midpalatal suture density to choose between rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME). This study revealed a significant increase in the midpalatal suture density after puberty. Thus, it may better to perform RME before puberty.

Midpalatal suture: evaluation of the morphological maturation stages via bone density.

BACKGROUND: To investigate the relationship between the morphological maturation stages of the midpalatal suture and its bone densities. METHODS: The sample consisted of 91 subjects aged 8-18 years who underwent cone beam computed tomography. All images were examined to classify morphological maturation of the midpalatal suture to five groups according to Angelieri et al. Bone density of the midpalatal suture was measured at the maxillary and palatal regions. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the difference between groups. RESULTS: Bone density of the midpalatal suture was significantly higher in the palatal region in E stage and in the maxillary region in D and E stages. CONCLUSIONS: It is concluded that the change in bone density of the midpalatal suture between the morphological maturation stages supports their reliability in clinical application.

Correlation between Cervical Vertebrae Volume Parameter and the Skeletal Maturation Status.

AIM: Assessing skeletal maturity is a critical factor in orthopedic treatment and orthognathic surgery. Quantitative methods have been suggested to decide the skeletal age. This study aims to assess the correlation between the middle phalanx of the third finger (MP3) method and cervical vertebral volume parameters (CVVP) in skeletal age determination. MATERIALS AND METHODS: This cross-sectional study was conducted on 21 boys and 29 girls between the ages of 8 and 16 years, who were divided into five groups of skeletal maturation: 100 MP3 radiographs and cone beam computed tomography (CBCT) were obtained and analyzed. Middle phalanx of the third finger maturation stages were evaluated according to Perinetti method (stages F-FG-G-H-I). The CVVP was determined on CBCT using Mimics Medical software. Analysis of variance (ANOVA) and Bonferroni tests were utilized to investigate the differences in volumetric parameters between MP3 stages. Spearman correlation coefficient was employed to obtain the correlation between MP3 stages and the CVVP. RESULTS: The differences in CVVP concentrated between MP3-I stage and the previous stages, with the highest values those for the 4th vertebra. Spearman test revealed a significant highest correlation between MP3 stages and the CVVP in the 4th vertebra; the lowest was in the 2nd, which was higher in the girls group. CONCLUSION: Strong level of agreement between the two methods was significant in the 4th vertebra. CLINICAL SIGNIFICANCE: Measurement of volumes of the 4th CVVP could be used as simple quantitative analysis in clinical practice to evaluate the maturity in orthodontic patients.

Volumetric upper airway changes following a new technique for Surgically-Assisted Maxillary Expansion (SAME).

BACKGROUND: Skeletal maxillary constriction (SMC) is one of the common skeletal discrepancies which are associated with alterations in the respiratory function. Today, many surgical techniques are used to expand the maxilla in adult patients with no consensus about the optimal technique. OBJECTIVES: The present study aimed to investigate the changes of the upper airway volume resulting from the use of a new, minimally invasive surgically-assisted maxillary expansion (SAME) technique, and compare the results with the conventional SAME technique. MATERIAL AND METHODS: A prospective study was conducted between September 2015 and July 2018. A total of 28 adult patients (11 males, 17 females; mean age: 19.1 ±2.7 years) with SMC underwent SAME. The sample was divided according to the applied surgical technique into 2 groups: the conventional osteotomy SAME (CO­SAME) group consisted of 13 patients (18.7 ±2.2 years) and the selective osteotomy SAME (SO-SAME) group consisted of 15 patients (19.4 ±3.2 years). Cone beam computed tomography (CBCT) scans were initially obtained preoperatively (T1) and 3 months post expansion (T2). The upper airway was divided into 2 segments: retropalatal and retroglossal. The volume of each segment and the total airway volume (TAV) were assessed using the OnDemand3D® software. RESULTS: The total upper airway volume showed a significant increase after both CO­SAME and SO-SAME (1.29 ±0.26 cc and 1.21 ±0.19 cc, respectively), with significant increases in retropalatal and retroglossal airway volumes (RPAV and RGAV) after both CO­SAME and SO-SAME (RPAV - 0.73 ±0.10 cc and 0.83 ±0.10 cc, and RGAV - 0.56 ±0.23 cc and 0.38 ±0.23 cc, respectively). No significant differences were observed in the maxillary width (MW), TAV or RGAV between the 2 SAME techniques, whereas the increase in RPAV in the SO-SAME group was significantly greater than that of the CO­SAME group. CONCLUSIONS: The new, minimally invasive SAME technique was an effective procedure to increase MW and the upper airway volume.

Micro-tensile bond strength to surface and subsurface enamel.

UNLABELLED: Testing of bond strength to enamel has been undertaken on both surface and subsurface enamel on the assumption that it is the same substrate. Over recent years, the micro-tensile method has become widely used for the evaluation of dental adhesives. However, there have been no micro-tensile bond strength studies comparing surface and subsurface enamel using orthodontic adhesives. It has been proposed that the bond strength to subsurface enamel is greater than that to surface enamel. OBJECTIVE: The micro-tensile bond strength (MTBS) of Transbond (light activated paste, 3 M Unitek, USA) to surface and subsurface enamel was investigated. METHODS: Ten sound freshly extracted lower human first molars were divided into two groups of five each. Surface enamel of the first group was removed with 500-grit silicone carbide paper, whilst in the second group it was left intact. Gelatin capsules filled with Transbond composite paste were bonded perpendicular to the enamel using light cure adhesive Primer (Transbond XT, 3 M Unitek, USA) in both groups, and stored in distilled water at 37 degrees C for 24 h. Crowns of all specimens were sectioned bucco-lingually into vertical slabs of approximately 0.6 mm thickness. Slabs in each group were prepared into an hourglass shape of 1mm width and 0.6 mm thickness. Micro-tensile bond strength was determined using a mini tensile testing machine (COMPACT Gauge, DILLON). RESULTS: Mean values of MTBS were: 31.2 MPa (SD14.5) for surface enamel and 47.9 (SD15.0) for subsurface enamel. SIGNIFICANCE: There was a significant difference between the two groups P = 0.001. It was concluded that subsurface enamel has significantly higher bond strength than surface enamel. This has implications for bonding in restorative dentistry and orthodontics.