Manual and mechanical stripping-induced enamel roughness and elemental composition in vivo.

OBJECTIVES: Interproximal enamel reduction (IPR) is routinely used in orthodontics to generate small to moderate amounts of space within the dental arch. Aim of this ex vivo study was to evaluate the effect of two different IPR systems on the enamel surface's waviness, roughness, and elemental composition after 6 months of intraoral exposure. MATERIALS AND METHODS: Fifteen orthodontic extraction patients were included in the present study. The 39 healthy premolars, which were scheduled to be extracted, were subjected to IPR at least 6 months before their extraction. IPR was performed on their mesial side with two different methods: (1) instrumented method with the Ortho-Strips system (on handpiece) and (2) manually with the Intensiv ProxoStrip (strips)-each with four different grits for contouring, finishing, and polishing. The distal side of each premolar served as its own internal control. Treated and untreated tooth surfaces were evaluated by optical profilometry, Raman, and scanning electron microscope/X-ray energy-dispersive (EDX) analyses. Data were analysed with descriptive statistics and generalized linear models at alpha = 5%. RESULTS: Both IPR methods significantly reduced the waviness of the enamel surface (P < 0.001), with manual IPR leading to smaller waviness reductions than the instrumented IPR (P ≤ 0.001). On the other side, both IPR methods led to a significant increase in enamel surface roughness (P < 0.001), with no significant differences between IPR methods. EDX and Raman analyses did not demonstrate any alterations on elemental composition of enamel after at least 6 months of intraoral exposure. CONCLUSIONS: Both stripping systems led to a flatter but rougher enamel surface. Further polishing is needed to restore the initial enamel smoothness. The elemental composition of the stripped enamel returns to the baseline level after 6 months of intraoral exposure.

The effect of mastic mouthwash on halitosis and oral hygiene in orthodontic patients: a randomized clinical trial.

BACKGROUND/OBJECTIVES: The aim of this trial was to investigate the effect of mastic mouthwash on halitosis using as a proxy the levels of the Volatile Sulfur Compounds (VSCs), and the effect on plaque and gingival indices in adolescents undergoing orthodontic treatment with fixed conventional labial appliances. SUBJECTS/METHODS: The study was a double-blinded, placebo-controlled, parallel-group, randomized clinical trial. Thirty patients with fixed orthodontic appliances were randomly allocated at a 1:1 ratio, to either the mastic-mouthwash or the placebo-mouthwash group. Eligibility criteria included ages between 13 and 18, active orthodontic treatment with fixed appliances, good general health, and total initial VSCs levels above 150 ppb. The primary outcome was the objective hydrogen sulfide (H2S) level, measured with the Oral ChromaTM device. The secondary outcomes were (1.) the methyl-mercaptan (CH3SH) and (2.) dimethyl sulfide [(CH3)2S] levels, measured with the same device, (3.) the subjective perception of the own malodour via questionnaires, and (4.) the oral hygiene assessed with the use of the Modified Silness and Löe Plaque Index (PI-M) and the Silness and Löe Gingival Index (GI) at baseline (T0) and after 2 weeks (T1). Stratified randomization by gender was used, and allocation was concealed with opaque numbered sealed envelopes. RESULTS: H2S level dropped from 221.00 ppb (T0) to 125.00 ppb (T1), and the difference between treatment groups was statistically significant in favour of the mastic group (coef: 72.34, 95% CI: 8.48, 136.27, P = 0.03). The levels of the other VSCs, the subjective measurements of oral malodour, and the oral hygiene indices did not differ between treatment arms. LIMITATIONS: The objective organoleptic assessment by a calibrated examiner was not performed. CONCLUSIONS/IMPLICATIONS: Mastic mouthwashes could be an alternative treatment for adolescent patients suffering from halitosis during orthodontic treatment with fixed appliances. REGISTRATION: The trial was registered at ClinicalTrials.gov (identifier: NCT05647369).

Relapse 1 week after bracket removal: a 3D superimpositional analysis.

OBJECTIVES: To measure tooth movement 1 week post-treatment and assess potential correlation with changes invoked during treatment. SUBJECTS AND METHODS: Thirty-eight patients were recruited (19 males, 19 females). Polyvinyl siloxane impressions were taken after bracket debonding (T1) and 1 week later (T2) and digitally scanned. During this period no retention was used. The digital casts were superimposed on structures of the hard palate. Translation and rotation of the first molars, canines, and central incisors were recorded. Additionally, movement of these teeth was assessed from the beginning (T0) until the end of treatment (T1). The correlation between the post-treatment relapse (T1-T2) and tooth movement during treatment (T0-T1) was investigated via the Spearman correlation coefficient. RESULTS: Relapse was detected and reflected changes in tooth position during treatment. For the first molars (right, left) the correlation between treatment and post-treatment tooth movement was evident in the transverse direction (r = -0.38, P = 0.020; r = -0.32, P = 0.052), tipping (r = -0.40, P = 0.015; r = -0.34, P = 0.034) and the antero-posterior direction (r = -0.31, P = 0.061; r = -0.36, P = 0.027); for the canines (right and left), as rotation around their long axis (r = -0.55, P = 0.003; r = -0.58, P = 0.002); for central incisors (right and left) in the antero-posterior direction (r = -0.55, P = 0.000; r = -0.48, P = 0.03), transverse direction (r = -0.43, P = 0.07; r = -0.32, P = 0.047), and rotation around their long axis (r = -0.53, P = 0.001; r = -0.28, P = 0.089). CONCLUSIONS: Post-treatment changes in tooth position were mostly related to tooth movement during treatment. The reported correlations may help clinicians predict short-term relapse, evaluate long-term retention need, and design individualized retention schemes.

A study of the mechanical properties of as-received and intraorally exposed single-crystal and polycrystalline orthodontic ceramic brackets.

BACKGROUND: Although ceramic brackets have been extensively used for decades in orthodontics there is not till today any study focusing on the possible deterioration of mechanical properties after in vivo ageing. OBJECTIVES: To determine whether the mechanical properties of alumina orthodontic brackets change after intraoral ageing thereby assessing the validity of a theoretical model established for the performance of ceramics in wet environments. MATERIALS AND METHODS: Two alumina brackets, one single crystal (Radiance, American Orthodontics, Sheboygan, WI) and one polycrystalline (Clarity, 3M, St. Paul, MN) were included in this study. Ten brackets for each group were collected from different patients after a minimum of 3-month intraoral exposure, whereas as-received brackets of the same manufacturers were used as controls. The specimens were subjected to Raman spectroscopy and were then embedded in epoxy resin and metallographic ground and polished. The mechanical properties of four groups (radiance control: RAC, radiance-retrieved RAR, clarity control: CLC and clarity-retrieved CLR) were determined using instrumented indentation testing according to ISO 14577-2002. The mechanical properties tested were Martens hardness (HM), indentation modulus (EIT), the ratio of elastic to total work, commonly known as elastic index (ηIT), and fracture toughness (KIC). The numerical results were statistically analysed employing two-way analysis of variance (ANOVA) and Tukey multiple comparison test at a = 0.05. RESULTS: Raman analysis revealed that both brackets are made of a-Al2O3 (corundum). No statistically significant differences were found for HM (N/mm2): RAC = 7249 (1507), RAR = 6926 (1144), CLC = 8052 (1360), CLR = 7390 (2393), or for EIT (GPa): RAC = 141 (27), RAR = 139 (23), CLC = 139 (28), CLR = 131 (47). However, significant differences were identified between the two alumina brackets tested for ηIT (%): RAC = 55.7 (4.2), RAR = 54.0 (3.5), CLC = 62.5 (4.4), CLR = 61.8 (4.7), while KIC was measured only for the polycrystalline bracket (Clarity) because of the complicated fractured pattern of the single-crystal bracket. Both brackets share equal HM and EIT before and after orthodontic intraoral ageing. LIMITATIONS: Whereas the study assessed the changes after intraoral exposure per theoretical model, which describes the reduction of critical stress to induce fracture after wetting, long-term intraoral ageing could have induced more pronounced effects. CONCLUSIONS/IMPLICATIONS: The results of this study indicate that 3 months of intraoral ageing do not change the mechanical properties of single-crystal and polycrystalline orthodontic brackets tested, thus indicating that the Griffith theory may not be applied to the case of manufactured ceramic brackets owing possibly to internal defects.

Monitoring regression of post-orthodontic lesions with impedance spectroscopy: a pilot study.

OBJECTIVE: To investigate if the alternating current impedance spectroscopy (ACIS) technology could be used to monitor remineralization of post-orthodontic white spot lesions (WSLs) after debonding of fixed orthodontic appliances. MATERIAL AND METHODS: The study group consisted of 28 adolescents (aged 12-16 years) with at least two WSLs on their maxillary incisors, canines, or first premolars at debonding. Buccal surfaces (n = 194) were visually examined and scored with modified International Caries Detection and Assessment System (ICDAS) criteria and with the CarieScan Pro device by three examiners according to manufactures manual (test method). In addition, 31 surfaces with ICDAS = 0 were monitored by ACIS, serving as controls. Follow-up examinations were carried out after 8 and 16 weeks. Modified ICDAS scores, captured from digital photographs by three independent examiners, served as reference method. Four patients were lost to follow-up. Data were analysed in a mixed statistical model considering systematic effects of visit, tooth and observer, random effects of patients, and visits within patients. RESULTS: Over 50 per cent of all surfaces had marked WSL at baseline and the corresponding values at 8 and 16 weeks were 33 per cent and 22 per cent. The ACIS readings mirrored the visual scores; the baseline estimate (56.3) was significantly decreased after 8 weeks (P < 0.05). The lateral incisors exhibited the highest values whereas the lowest were recorded for the central incisors. LIMITATIONS: ICDAS is not the same as a 'true' gold standard. The high prevalence of WSL may jeopardize the external validity. CONCLUSION: The ACIS technology may to some extent be used to monitor the regression of post-orthodontic WSLs.

Enamel gloss changes induced by orthodontic bonding.

OBJECTIVE: The purpose of this study was to assess enamel gloss changes induced by orthodontic bracket bonding with a light-cured composite or a light-cured resin-reinforced glass ionomer cement. SETTING: The Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Greece. DESIGN: Laboratory study. METHODS: A total of twenty extracted upper human first premolars were included in this study and each tooth served as a control for itself. Their buccal surfaces were subjected to 60o-angle gloss measurement (G%60) with a standardized and secure repeated analysis of the same site. After baseline evaluation, a bracket was bonded on the buccal surface of each tooth. Half of the specimens were bonded with acid-etching and a light-cured composite whereas the other half with a light-cured resin-reinforced glass ionomer cement without prior enamel conditioning. Gloss measurements were repeated after bracket debonding and removal of the composite/glass ionomer cement with an 18-fluted carbide bur. Gloss differences between the two measurement conditions (baseline and post-debonding) were analyzed through linear regression with standard errors derived using the bootstrap method. Level of significance was set at a < 0.05. RESULTS: A statistically significant difference was detected between the tested groups for the outcome of interest. Teeth bonded with light-cured composite exhibited larger enamel gloss changes as compared to resin-reinforced glass ionomer cement (ß = 0.74; 95% CIs: 0.10, 1.38; p = 0.02). CONCLUSIONS: Bracket bonding with two common bonding protocols (acid-etching with a light-cured composite vs. no etching with resin reinforced glass-ionomer cement) and subsequently debonding and adhesive removal with an 18-fluted carbide bur induced enamel gloss changes.

Torque differences according to tooth morphology and bracket placement: a finite element study.

INTRODUCTION: Torque of the maxillary incisors is essential in esthetics and proper occlusion, while torque expression is influenced by many factors. The aim of this finite element study was to assess the relative effect of tooth morphology, bracket prescription, and bracket positioning on tooth displacement and developed stresses/strains after torque application. METHODS: A three-dimensional upper right central incisor with its periodontal ligament (PDL) and alveolus was modelled. The tooth varied in the crown-root angle (CRA) between 156°, 170°, and 184°. An 0.018-inch slot discovery® (Dentaurum, Ispringen, Germany) bracket with a rectangular 0.018 × 0.025-inch ß-titanium wire was modelled. Bracket torque prescription varied between 0°, 12°, and 22°, with bracket placement at the centre of the middle, gingival or incisal third of the crown. A total of 27 models were generated and a buccal root torque of 30° was applied. Afterwards, crown and apex displacement, strains in the PDL, and stresses in the bracket were calculated and analysed statistically. RESULTS: The palatal crown displacement was significantly affected by bracket positioning (up to 94 per cent), while the buccal apex displacement was significantly affected by bracket prescription (up to 42 per cent) and bracket positioning (up to 23 per cent). Strains in the PDL were affected mainly by CRA (up to 54 per cent), followed by bracket positioning (up to 45 per cent). Finally, bracket prescription considerably affected the stresses in the bracket (up to 144 per cent). LIMITATIONS: These in silico results need to be validated in vivo before they can be clinically extrapolated. CONCLUSION: Tooth anatomy and the characteristics of the orthodontic appliance should be considered during torque application.

Microstructural and mechanical characterization of contemporary lingual orthodontic brackets.

OBJECTIVES: To investigate the composition and the microstructural and mechanical characterization of three different types of lingual brackets. MATERIALS AND METHODS: Incognito™ (3M Unitek), In-Ovation L (DENTSPLY GAC) and STb™ (Light Lingual System, ORMCO) lingual brackets were studied under the scanning electron microscope employing backscattered electron imaging and their elemental composition was analysed by energy-dispersive X-ray microanalysis. Additionally, Vickers hardness was assessed using a universal hardness-testing machine, and the indentation modulus was measured according to instrumented indentation test. Two-way analysis of variance was conducted employing bracket type and location (base and wing) as discriminating variable. Significant differences among groups were allocated by post hoc Student-Newman-Keuls multiple comparison analysis at 95% level of significance. RESULTS: Three different phases were identified for Incognito and In-Ovation L bracket based on mean atomic number contrast. On the contrary, STb did not show mean atomic contrast areas and thus it is recognized as a single phase. Incognito is a one-piece bracket with the same structure in wing and base regions. Incognito consists mainly of noble metals while In-Ovation L and STb show similar formulations of ferrous alloys in wing and base regions. No significant differences were found between ferrous brackets in hardness and modulus values, but there were significant differences between wing and base regions. Incognito illustrated intermediate values with significant differences from base and wing values of ferrous brackets. CONCLUSIONS/IMPLICATIONS: Significant differences exist in microstructure, elemental composition, and mechanical properties among the brackets tested; these might have a series of clinical implications during mechanotherapy.

Effect of mandibular third molars on crowding of mandibular teeth in patients with or without previous orthodontic treatment: a systematic review and meta-analysis.

OBJECTIVES: To assess the scientific evidence related to the role of the mandibular third molars on the late crowding of the lower anterior teeth in patients with or without previous orthodontic treatment. The secondary outcomes included changes in mandibular arch width and arch length. MATERIALS AND METHODS: The databases PubMed, Scopus, ProQuest, and Google Scholar were searched from inception until April 2022. The included papers were studies evaluating the role of mandibular third molars on crowding of mandibular anterior teeth in patients of any age and gender, with mandibular third molars impacted or semi-impacted or erupted. Predetermined and prepiloted data collection forms were used to record the necessary information. RESULTS: Thirteen observational studies were included in the present systematic review. Most of them were assigned an overall risk of bias of moderate risk while the rest of them were at high risk. Four studies found an association between the presence of mandibular third molar and mandibular incisor crowding. Finally, seven studies were included in the quantitative analysis. Three different meta-analyses were conducted: for patients (a) with or (b) without previous orthodontic treatment and (c) in combination for patients with and without previous orthodontic treatment. According to the pooled results of all three meta-analyses, random effects model yielded a significant benefit for those without third molars compared to those with third molars regarding crowding, mean Little's irregularity index and mean arch length. CONCLUSIONS: Lower third molars may contribute to mandibular crowding and lower arch constriction. Further prospective research of high quality is needed to clarify the impact of third molars on anterior mandibular crowding.

The effect of freezing on the fracture pattern of adhesive on debonding: an in-vitro study.

The purpose of this study was to quantitatively evaluate adhesive remnants on the enamel surface following bracket debonding using a freezing element. Thirty-six sound premolars were used in this study. In each case, a bracket was bonded onto each tooth with conventional light-cured composite resin and de-bonded after one week. Freezing of the underlying composite through the bracket was performed immediately before debonding with a portable cryosurgical system (-55 °C). Specimens were divided into three groups according to the duration of freezing: a control group without freezing was used as a reference and two interventional groups with different durations of freezing (15 or 40 s). Brackets were removed by using debonding pliers to squeeze the wings of the bracket in an occluso-gingival manner. Adhesive remnants on the tooth were then quantitatively evaluated by stereo-microscopy. Pearson's Chi-squared test was used to investigate the relationship between the proportion of remaining resin and the group of teeth. In the control group, 100% of the composite remained on the enamel surface of all specimens. Significantly less adhesive remnants were found in the intervention groups (p = 0.001 for the 15 s group and p = 0.043 for the 40 s group). There was no significant difference between the two interventions (p = 0.165) in terms of the proportion of remaining adhesive remnants. Freezing of the bracket and the underlying adhesive resin prior to bracket debonding may favorably alter the behavioral pattern of composite fracture, thus reducing the extent of adhesive remnants on the enamel. Increasing the freezing time from 15 to 40 s did not exert significant effects on adhesive remnants following debonding. Further research now needs to investigate the effect of freezing on the mechanical properties of the adhesive remnants and its in-vivo effect on pulp vitality over both short- and long-terms.

Metabolic Bone Diseases Affecting Tooth Eruption: A Narrative Review.

Tooth eruption is an essential process for the development of the oral and maxillofacial system. Several inherited and acquired diseases might affect this tightly regulated process, resulting in premature, delayed, or even failed tooth eruption. The purpose of this article is to review the literature and the clinical parameters of metabolic bone diseases that affect tooth eruption. It examines the physiological aspects of tooth eruption and the pathophysiological changes induced by metabolic bone diseases, including changes in bone metabolism, density, and structure. The search strategy for this review included an electronic search in PubMed, Google Scholar, Medline, Scopus, and the Cochrane Library using the following keywords: "metabolic bone diseases", "tooth eruption", "delayed tooth eruption", and each reported disease in combination with "tooth eruption disorders", covering publications up to March 2024 and limited to English-language sources. Understanding the influence of metabolic bone diseases on tooth eruption is crucial for managing both dental and skeletal manifestations associated with these disorders. This review suggests that a multidisciplinary approach to treatment may significantly improve oral outcomes for patients suffering from such conditions. Clinicians should be aware of the specific dental abnormalities that may arise and consider comprehensive evaluations and individualized treatment plans. These findings underscore the need for further research into targeted therapies that address these abnormalities.

Correlations among satisfaction parameters after orthodontic treatment.

OBJECTIVE: This study assessed patient's satisfaction after orthodontic treatment in the postgraduate orthodontic clinic of the Dental School at the University of Athens (Athens, Greece), and investigated possible correlations between satisfaction after orthodontic treatment and life satisfaction, alongside the influence of age, gender, severity of initial orthodontic malocclusion and duration of retention period. MATERIAL AND METHODS: Patients aged 12 years and above, who had recently completed comprehensive orthodontic treatment, participated completing two questionnaires: a 37-item questionnaire, validated for assessing orthodontic treatment satisfaction; and the 5-item Satisfaction with Life Scale, a valid and reliable measure of life satisfaction. Scores from each questionnaire were summed for each patient. Demographic details, Index of Orthodontic Treatment Need (IOTN) and the duration of the retention period up to questionnaire completion were collected. Multiple regression analysis assessed the relationship between the questionnaires and the evaluated variables. RESULTS: A total of 150 patients answered the questionnaires, being 82 women (55%) and 68 men (45%). The mean age of patients was 18.87 ± 5.97 years (range: 12-47). Most patients expressed satisfaction with treatment outcomes (grades 5 and 6). Satisfaction with orthodontic treatment showed a significant correlation with life satisfaction (p=0.002), but not with gender, age, dental/esthetic components of IOTN, or the duration of the retention period. CONCLUSION: Satisfaction after orthodontic treatment exhibited a significant correlation with life satisfaction, but it was not affected by gender, age, dental/esthetic components of IOTN, or the duration of the retention period.

Effect of aligners on patients' oral health-related quality of life and anxiety: a prospective pilot study.

BACKGROUND: This prospective study explored the impact of aligners on the oral health-related quality of life and anxiety of patients during the first month of orthodontic treatment and the first month of the retention phase. METHODS: A total of 23 male and female patients (median age 25 y) treated with clear aligners were included. The OHRQoL questionnaire was used at certain time points during treatment (T1: placement of the first aligner; T2: after one day of use; T3: after seven days; T4: after one month; and T5: after one month in the retention phase). The State-Trait Anxiety Inventory (STAI) was also self-administered to assess state and trait anxiety (Y1 and Y2 subscales, respectively) at the T1, T4 and T5 time points. A population average generalized estimating equations logistic regression model was fit to assess the effect of time on the responses, and the Wald test was used to examine the overall effect of time. RESULTS: Overall time was a significant predictor for most of the questions. However, time was marginally significant for the OHRQoL questions evaluating oral symptoms such as bad taste/smell, sores, and food accumulation. Tooth discolouration did not differ between time points. The general activity disturbance was significantly lower in the retention phase. Higher depression and anxiety scores were reported at the initial appointment and decreased thereafter. CONCLUSIONS: CAT has a negative impact on quality of life and psychological status during the initial days of treatment. These impairments ameliorate at later treatment stages.

Inter-examiner Reliability of Two Methods for Scoring Post-Orthodontic White Spot Lesions from Digital Photographs.

Objective: To compare the reliability of two scoring systems for detecting white spot lesions (WSLs) from clinical photographs captured during debonding of fixed orthodontic appliances. Methods: Digital images of 58 healthy adolescents (34 females and 24 males) were examined, depicting 384 buccal surfaces of maxillary incisors, canines, and first premolars. Three trained examiners (E1, E2 and E3) independently evaluated the fully anonymized photos in a randomized order using the Gorelick index (GI) and the modified International Caries Detection and Assessment System (ICDAS II). A 1-2-week interval separated the scorings. Spearman's rank correlation coefficient, Fisher's z-test, and the interclass correlation coefficient (ICC) were applied to compare the scoring methods and express examiner agreement. Results: The two scoring systems showed a moderate to strong positive relationship, but inter-examiner variations were significant (p<0.05). We found moderate to good reliability (ICC 0.60 to 0.84) with the ICDAS II system and good to excellent values with the GI (ICC 0.72 to 0.94), depending on the examiner. The agreement concerning the sound surfaces and the most severe WSLs was perfect, whereas the scoring of the milder lesion stages appeared more uncertain. Conclusion: A moderate to strong positive relationship was demonstrated between the two methods when scoring the presence and severity of WSLs from digital images. Significant inter-examiner variations affected reliability.

A comparative assessment of torque generated by lingual and conventional brackets.

The aim of this study was to assess the effect of bracket type on the labiopalatal moments generated by lingual and conventional brackets. Incognito™ lingual brackets (3M Unitek), STb™ lingual brackets (Light Lingual System; ORMCO), In-Ovation L lingual brackets (DENTSPLY GAC), and conventional 0.018 inch slot brackets (Gemini; 3M Unitek) were bonded on identical maxillary acrylic resin models with levelled and aligned teeth. Each model was mounted on the orthodontic measurement and simulation system and 10 0.0175 × 0.0175 TMA wires were used for each bracket type. The wire was ligated with elastomerics into the Incognito, STb, and conventional brackets and each measurement was repeated once after religation. A 15 degrees buccal root torque (+15 degrees) and then a 15 degrees palatal root torque (-15 degrees) were gradually applied to the right central incisor bracket. After each activation, the bracket returned to its initial position and the moments in the sagittal plane were recorded during these rotations of the bracket. One-way analysis of variance with post hoc multiple comparisons (Tukey test at 0.05 error rate) was conducted to assess the effect on bracket type on the generated moments. The magnitude of maximum moment at +15 degrees ranged 8.8, 8.2, 7.1, and 5.8 Nmm for the Incognito, STb, conventional Gemini, and the In-Ovation L brackets, respectively; similar values were recorded at -15 degrees: 8.6, 8.1, 7.0, and 5.7 Nmm, respectively. The recorded differences of maximum moments were statistically significant, except between the Incognito and STb brackets. Additionally, the torque angles were evaluated at which the crown torque fell well below the minimum levels of 5.0 Nmm, as well as the moment/torque ratio at the last part of the activation/deactivation curve, between 10 and 15 degrees. The lowest torque expression was observed at the self-ligating lingual brackets, followed by the conventional brackets. The Incognito and STb lingual brackets generated the highest moments.

Torque expression of 0.018 and 0.022 inch conventional brackets.

The aim of this study was to assess the effect of the moments generated with low- and high-torque brackets. Four different bracket prescription-slot combinations of the same bracket type (Mini Diamond® Twin) were evaluated: high-torque 0.018 and 0.022 inch and low-torque 0.018 and 0.022 inch. These brackets were bonded on identical maxillary acrylic resin models with levelled and aligned teeth and each model was mounted on the orthodontic measurement and simulation system (OMSS). Ten specimens of 0.017 × 0.025 inch and ten 0.019 × 0.025 inch stainless steel archwires (ORMCO) were evaluated in the low- and high-torque 0.018 inch and 0.022 inch brackets, respectively. The wires were ligated with elastomerics into the brackets and each measurement was repeated once after religation. Two-way analysis of variance and t-test were conducted to compare the generated moments between wires at low- and high-torque brackets separately. The maximum moment generated by the 0.017 × 0.025 inch stainless steel archwire in the 0.018 inch brackets at +15 degrees ranged from 14.33 and 12.95 Nmm for the high- and low-torque brackets, respectively. The measured torque in the 0.022 inch brackets with the 0.019 × 0.025 inch stainless steel archwire was 9.32 and 6.48 Nmm, respectively. The recorded differences of maximum moments between the high- and low-torque series were statistically significant. High-torque brackets produced higher moments compared with low-torque brackets. Additionally, in both high- and low-torque configurations, the thicker 0.019 × 0.025 inch steel archwire in the 0.022 inch slot system generated lower moments in comparison with the 0.017 × 0.025 inch steel archwire in the 0.018 inch slot system.

A comparative assessment of forces and moments generated by lingual and conventional brackets.

The aim of this study was to assess the effect of bracket type on the labiopalatal forces and moments generated in the sagittal plane. Incognito™ lingual brackets (3M Unitek), STb™ lingual brackets (Light Lingual System; ORMCO), and conventional 0.018 inch slot brackets (Gemini; 3M Unitek) were bonded on three identical maxillary acrylic resin models, with a palatally displaced right lateral incisor. The transfer trays for the indirect bonding of the lingual brackets were constructed in certified laboratories. Each model was mounted on the orthodontic measurement and simulation system and ten 0.013 inch CuNiTi wires were used for each bracket type. The wire was ligated with elastomerics and each measurement was repeated once after re-ligation. The labiopalatal forces and the moments in the sagittal plane were recorded on the right lateral incisor. One-way analysis of variance and post hoc Scheffe pairwise comparisons were used to assess the effect on bracket type on the generated forces and moments. The magnitude of forces ranged from 1.62, 1.27, and 1.81 N for the STb, conventional, and Incognito brackets, respectively; the corresponding moments were 2.01, 1.45, and 2.19 N mm, respectively. Bracket type was a significant predictor of the generated forces (P < 0.001) and moments (P < 0.001). The produced forces were different among all three bracket types, whereas the generated moments differed between conventional and lingual brackets but not between lingual brackets.

Perceived Effects of Orthognathic Surgery versus Orthodontic Camouflage Treatment of Convex Facial Profile Patients.

Increased facial profile convexity has a common occurrence in the population and is a primary reason for seeking orthodontic treatment. The present study aimed to compare the perceived changes in facial profile appearance between patients treated with combined orthognathic/orthodontic treatment versus only orthodontic camouflage treatment. For this reason, 18 pairs of before- and after-treatment facial profile photos per treatment group (n = 36 patients) were presented to four types of assessors (surgeons, orthodontists, patients, laypeople). Ratings were recorded on 100 mm visual analogue scales depicted in previously validated questionnaires. All rater groups identified minor positive changes in the facial profile appearance after exclusively orthodontic treatment, in contrast to substantial positive changes (14% to 18%) following combined orthodontic and orthognathic surgery. The differences between the two treatment approaches were slightly larger in the lower face and the chin than in the lips. The combined orthodontic and orthognathic surgery interventions were efficient in improving the facial appearance of patients with convex profile, whereas orthodontic treatment alone was not. Given the significant influence of facial aesthetics on various life aspects and its pivotal role in treatment demand and patient satisfaction, healthcare providers should take these findings into account when consulting adult patients with a convex facial profile.

Adverse Effects of Surgically Accelerated Orthodontic Techniques: A Systematic Review.

Evidence on the potential adverse effects of surgically accelerated orthodontic techniques is scarce. The aim of this review was to evaluate the available scientific evidence regarding the adverse effects on periodontium, tooth vitality, and root resorption, associated with these surgical procedures in children, adolescents, and adults. The reporting of this review was based on the PRISMA2020 guidelines. Seven databases and three registers were searched for randomized clinical trials (RCTs) and controlled clinical trials (CCTs) published up to 22 June 2022. Hand searching of the reference lists of the included studies was also performed. The quality of the evidence was assessed with the Cochrane risk of bias and ROBINS-I tools. A total of 887 records were initially screened. Finally, 33 RCTs (713 patients), six CCTs (103 patients), and six ongoing protocols were eligible for this systematic review. The current review indicated that there are no significant adverse effects of surgically accelerated orthodontic techniques on periodontium, root length, or tooth vitality. High-quality clinical trials with less risk of bias should be conducted to allow reliable conclusions regarding the adverse effects of the surgical procedures associated with the acceleration of orthodontic treatment on children, adolescents, and adults.

Evaluation of Lateral Incisor Resorption Caused by Impacted Maxillary Canines Based on CBCT: A Systematic Review and Meta-Analysis.

BACKGROUND: Root resorption (RR) of the adjacent teeth due to upper canine impaction requires an appropriate modification of the orthodontic treatment plan and the mechanotherapy used. AIM: The aim of this review was to assess scientific evidence published during the last decade, concerning the prevalence of lateral incisor RR caused by impacted maxillary canines, based only on cone-beam computed tomography (CBCT). The location of RR on this tooth, as well as the prevalence of RR on the other adjacent teeth, were additionally evaluated. METHODS: This review followed the criteria specified by the PRISMA statement. Four databases were searched for articles published between January 2008 and June 2021. Predefined and piloted data collection forms were used to record the necessary information. RESULTS: A total of 5098 records were initially screened. Only seven articles were finally eligible for further analysis. A total number of 540 participants (176 males and 364 females) was derived from the included studies. RR of maxillary lateral incisors was common (50%). RR of mild severity was more common (62%), more frequently located in the middle (52%) and apical (42%) thirds of the root. CONCLUSIONS: Further research with more homogeneous groups is required.