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.

Descriptive analysis of the cases published in the Align® Global Gallery.

INTRODUCTION: Social media enhanced access to information, making it easier to share dental treatments. OBJECTIVE: This study aimed to conduct a descriptive analysis of the clinical cases published on the Align® Global Gallery platform. MATERIAL AND METHODS: A retrospective cross-sectional study of 1,582 cases was conducted, data extracted referred to the following basic information: case number; patient's age; reported gender; Invisalign® package modality; treatment time; aligner exchange protocol; total number of aligners per arch; type of retainers, and inclusion of initial and final panoramic and cephalometric radiographs. RESULTS: The majority were young (mean age 24.6 years, SD = 11.6), female patients (69.1%) with Class I malocclusion (39.4%) and crowding (77.9%). Comprehensive treatment was common (66.5%), with an average treatment time of 18 months (SD = 8.56; 95% CI = 17.6-18.5), with the most frequently reported aligner exchange protocol being 7 days (49.5%), with an average of 50.6 aligners in the upper arch (SD = 26.9; 95% CI = 49.2-51.9), and 48.7 in the lower arch (SD = 26.1; 95% CI = 47.4-50.0). Arch expansion (66.9%) and interproximal reduction (59.7%) were common approaches, while extractions were rare (4.3%). In most cases, initial lateral cephalometric (80.4%) and panoramic (93.3%) radiographs were presented. However, the final radiograph count dropped, with lateral cephalometric at 69.2%, and panoramic at 82.2% of cases. CONCLUSION: Cases in the Align®Global Gallery mostly feature Class I patients with crowded teeth, treated with expansion and interproximal reduction. The absence of standardized information and post-treatment data restricts the applicability of these findings to broader Invisalign® treatment trends.

Poly-Ether-Ether-Ketone versus dead-soft coaxial bonded retainers: a randomized clinical trial. Part 2: periodontal health and microbial biofilm assessment.

BACKGROUND: Retainers have the potential to detrimentally impact periodontal health and contribute to tooth decay. OBJECTIVES: To investigate periodontal health and bacterial biofilm related to Poly-Ether-Ether-Ketone (PEEK) fixed retainers as compared to Dead-soft coaxial fixed retainer (DSC). TRIAL DESIGN: A two-arm parallel groups single-centre randomized clinical trial. METHODS: The trial included patients whose orthodontic treatment was completed and required retainers. Participants were randomly assigned into two retainer groups: PEEK retainers, prepared by computer-aided design and manufacturing into 0.8 mm wire form, and DSC retainers. The objectives included assessing periodontal health through plaque accumulation index (PI), bleeding on probing (BOP), periodontal pocket depth (PPD), gingival index (GI), calculus index (CI), and alveolar bone height (ABH) assessment. Biofilm assessment involved bacteriological screening of aerobic, facultative anaerobic, mutans streptococci, and lactobacilli. The periodontal indices and microbiological screening as well as were assessed at the debonding stage (T0), 1-month (T1), 3-month (T3), and 6-month (T6) after the commencement of the trial, except for the ABH, which was recorded using periapical radiograph at T0 and T6. BLINDING: Single blinding of participants in addition to the bacteriological specialist. RESULTS: Initially, the trial enrolled 46 participants, aged between 12 and 28 years, and were randomly assigned to two groups, with 23 participants in each group. Subsequently, one participant withdrew from the trial, resulting in a total of 45 participants whose data were analysed. Assessment of the periodontal indices, excluding the CI (P = .480), revealed statistically but not clinically significant differences between groups after 6-month of retention (P = .016 of PI, P = .020 of BOP, P = .05 of PPD, and P = .01 of GI). There was slight plaque accumulation, normal PPD (approximately 1 mm), healthy to mild gingivitis with a GI of less than 1 and BOP was around 10%. Concerning the ABH, there was a noticeable reduction in its score after 6 months, particularly in the PEEK group, although the difference was not statistically significant (P = .102). Furthermore, the bacteriological viable count did not show any significant difference between the groups during the recall visits. HARMS: There have been no reported negative consequences. LIMITATIONS: Blinding the assessor of periodontal indices was not feasible due to the nature of the intervention. The trial follow-up duration was limited. CONCLUSIONS: Both the PEEK and DSC retainers have comparable impacts on periodontal health and bacterial accumulation and composition during the retention period. TRIAL REGISTRATION: NCT05557136.

Biofilm formation of Streptococcus mutans, Streptococcus sanguinis, Staphylococcus epidermidis, Staphylococcus aureus, Lactobacillus casei, and Candida Albicans on 5 thermoform and 3D printed orthodontic clear aligner and retainer materials at 3 time points: an in vitro study.

INTRODUCTION: Orthodontic clear aligners and retainers have numerous advantages that is making them ever increasingly popular. However, they might, similar to any other oral appliance, contribute to biofilm formation and finally dental caries or white spot lesions or gingival inflammations. The literature on biofilm formation on orthodontic clear appliances is very scarce and limited to a few microorganisms and materials. Therefore, this experimental study evaluated the biofilm formation on 5 thermoformed and 3D printed CAD/CAM orthodontic retainers in 3 intervals. METHODS: In this in vitro study, 345 specimens (270 test discs and 45 negative controls) were created from fabricated retainers. Retainers included a 3D printed CAD/CAM material (Detax) and four thermoformed retainers [Erkodent (polyethylene terephthalate glycol [PETG]); EasyVac (polyethylene); DB (polyester based on terephthalic acid); and Clear Tech]. They were all 1 mm thick, and all completely fabricated, i.e., heated or printed. The discs were placed in 96-well plates. Microorganisms were cultured on 270 discs for 24 h (90 discs), 72 h (90 other discs), and 5 days or 120 h (90 other discs). Biofilm formation of the strains and negative controls was measured using the microtiter plate assay by ELISA reading. The microbes' ability to produce biofilm was categorized based on the comparison of average optical density (OD) of tests versus a cut-off point OD (ODc) calculated as the average of the OD of corresponding negative controls plus 3× its standard deviation: non-biofilm former [OD ≤ ODc], weak biofilm former [ODc < OD ≤ (2 × ODc)], moderate biofilm former [(2 × ODc) < OD ≤ (4 × ODc)], and strong biofilm former [(4 × ODc) < OD]. These were also converted to ranked scores between zero (no biofilm) and 3. The difference between ODs with control ODs were calculated. These were analyzed using 3-way ANOVA, 2-way ANOVA, and Tukey tests (α = 0.05, α = 0.008). RESULTS: The 3-way ANOVA showed that the overall difference among the ΔODs of 5 retainers (all microorganisms and all intervals combined, n = 270) was not significant (F = 1.860, P = 0.119). Nevertheless, the difference among 3 intervals (F = 31.607, P = 0.0000) and the difference among the 6 microorganisms (F = 24.044, P = 0.0000) were significant. According to the Tukey test, the differences between the 1st interval with either of the other two intervals was significant (both P values = 0.000). There were significant differences between Candida albicans with all other organisms (all 5 P values = 0.0000). All other pairwise comparisons were insignificant (all 10 P values ≥ 0.1). After taking the averages of the 3 intervals, the order of the biofilm generation for different materials were as follows: Detax (average score: 1.56), Easyvac (1.67), Erkodent (1.78), Clear Tech (1.83), BD (2.28). CONCLUSIONS: As far as these 6 microorganisms are of concern, there might not be a significant overall difference among the clear retainer materials tested in this study. A significant overall increase was observed between the first and third days, which later did not significantly increase more until day 5. The Candida albicans biofilm was more intense than the tested 5 bacteria, which themselves showed rather similar growth patterns to each other.

The effects of fulvic acids and low-level laser therapy on orthodontic retention in rats.

BACKGROUND: Shortening retention time and minimizing relapse rates are ongoing challenges in orthodontics. This study investigated the effects of natural fulvic acids (FAs) and low-level laser therapy (LLLT) on orthodontic retention in rats. METHODS: Seventy-two male Sprague-Dawley rats underwent mesial movement of the left maxillary first molar using a 50 g force via a nickel-titanium tension spring. After three weeks of movement, the rats entered the retention phase with retainer wires and were divided into four groups: Control (no intervention), FAs (80 mg/kg orally daily), LLLT (808 nm laser twice weekly), and FAs + LLLT (both treatments). Retainers were removed on days 7, 14, and 21 for a 3-day relapse assessment. Maxillary impressions were analyzed for relapse rates using 3Shape software, alongside histological and immunohistochemical evaluations of bone morphogenetic protein-2 (BMP-2) expression in periodontal tissues, with differences among groups analyzed using an ordinary two-way analysis of variance (ANOVA). RESULTS: The relapse rate decreased over time, particularly at 10, 17, and 24 days (p < 0.001). The FAs group did not significantly affect relapse rates compared to the control group (p = 0.084). In contrast, both the LLLT and FAs + LLLT groups significantly reduced relapse rate (p < 0.001), with no significant difference between these groups (p = 0.555). Histological examination revealed active osteoclasts on day 10, decreasing by days 17 and 24. The LLLT and FAs + LLLT groups showed less local cementum resorption and better periodontal fiber arrangement. All treatment groups significantly increased BMP-2 expression (P < 0.05) compared to controls. with LLLT and FAs + LLLT differing significantly from FAs (P < 0.001), though no difference was observed between LLLT and FAs + LLLT (P = 0.578). CONCLUSIONS: FAs did not significantly reduce relapse rate with retainers, while LLLT effectively reduced relapse rates, showing no additional benefit from combining FAs with LLLT. Both FAs and LLLT increased BMP-2 expression in PDL fibroblasts but with no synergistic effect.

Poly-ether-ether-ketone (PEEK) versus dead-soft coaxial bonded retainers: a randomized clinical trial. Part 1. Stability, retainer failure, and participant satisfaction.

BACKGROUND: Poly-ether-ether-ketone (PEEK) was introduced in dentistry as an alternative to metal alloys. OBJECTIVE: To assess the effectiveness of PEEK-fixed retainers in preserving the stability of mandibular anterior and participant satisfaction as compared to the Dead-soft coaxial fixed retainer (DSC). TRIAL DESIGN: A single-centre, two-arm parallel groups randomized clinical trial. METHODS: The patients treated with pre-adjusted orthodontic appliances who have a Little's Irregularity Index (LII) ≤ 0.5 mm have been enrolled in the trial. PEEK retainers were prepared to round 0.8 mm wire by computer-aided design and manufacturing, and the DSC wire was carefully adapted to the lingual surface of the lower anterior teeth. The primary outcome was the stability of lower anterior teeth as assessed by LII, while the secondary outcomes were changes in occlusal parameters, retainer failure, and patient satisfaction. The data were collected at the debonding stage (T0), 1 month (T1), 3 months (T3), and 6 months (T6) after starting the trial, except for patient's satisfaction, which was recorded using an electronic form at T1 and T6. BLINDING: Single blinding of participants. RESULTS: A total of 46 participants with an age range of 12-28 years old were randomly allocated to the two groups (n = 23 in each). Only one participant dropped out; therefore, 45 participants were analysed. The DSC group showed a significant increase in LII at T3. Both retainer groups had comparable occlusal measurements, failure frequency, and survival time, with no significant difference. The patients in the DSC group reported a statistically significant perception of change in the position of their teeth compared to those in the PEEK group. HARMS: No harmful effects have been reported. LIMITATIONS: Limited follow-up duration and the inability to blind the operator due to the nature of the intervention. CONCLUSIONS: After 6-month retention, the PEEK retainer was equally effective to DSC retainers in maintaining the teeth alignment, with no significant differences regarding the failure frequency, survival rate, and general patient satisfaction. TRIAL REGISTRATION: https://register.clinicaltrials.gov. (NCT05557136).

CAD/CAM-BASED FIXED LINGUAL ORTHODONTIC RETAINERS MAY BE AS EFFECTIVE AS CONVENTIONAL FIXED RETAINERS.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Bardideh E, Ghorbani M, Shafaee H, Saeedi P, Younessian F. A comparison of CAD/CAM- based fixed retainers versus conventional fixed retainers in orthodontic patients: a systematic review and network meta-analysis. Eur J Orthod. 2023 Sep 18;45(5):545-557. doi:10.1093/ejo/cjad033. PMID: 37471113. SOURCE OF FUNDING: The study was not funded. TYPE OF STUDY/DESIGN: Systematic review with network meta-analysis.

Can vacuum-formed retainers maintain arch dimensions and alignment compared to Hawley and fixed bonded retainers after treatment with fixed appliances? A systematic review and meta-analysis.

BACKGROUND: Different types of retention appliances have been proposed over the years, but their effectiveness in maintaining arch dimensions and alignment after orthodontic treatment is still unclear. AIM: To assess the efficacy of vacuum-formed retainers (VFRs) in preserving arch widths, arch length, and anterior alignment in maxillary and mandibular arches, compared to removable Hawley retainers (HRs) or fixed bonded retainers (FBRs). Search methods: unrestricted literature search of five major databases up to March 2024. SELECTION CRITERIA: randomized/non-randomized clinical studies comparing VFRs to removable HRs or FBRs. DATA COLLECTION AND ANALYSIS: after duplicate study selection, data extraction, and risk of bias assessment, random effects meta-analyses of standardized mean differences and their 95% confidence intervals were performed, followed by meta-regressions, sensitivity analyses, and assessment of the quality of evidence with GRADE. RESULTS: Twenty-two prospective studies (4 non-randomized and 18 randomized controlled trials) involving 1797 patients (mean age 17.01 years, 38.3% males) were included. No significant differences were found in the intercanine width, intermolar width, and arch length between VFRs and HRs, in both arches (P > 0.05). However, VFRs were statistically more effective than HRs in terms of Little's irregularity scores (LII) in the maxilla (eight studies; SMD = -0.42; 95% CI: -1.03 to -0.09; P = 0.02; I2 = 73.4%) but not in the mandible (P = 0.12). No significant differences were reported for all considered outcomes between VFRs and FBRs in in both arches (P > 0.05), except for lower LII, where VFRs were significantly less efficient (eight studies; SMD = 1.49; 95% CI = 0.26-2.7; P = 0.02; I2 = 93%). Follow-up times, risk of bias, and wire type (of FBRs) did not show statistically significant effects on outcome variables. Sensitivity analyses showed robustness of the findings for including non-randomized and postretention studies. The certainty in these estimates was from moderate to low due to the risk of bias and inconsistency. CONCLUSIONS: Low to moderate quality evidence indicates that VFRs are as effective as HRs in maintaining arch widths, length, and alignment. Low-quality evidence found similar efficacy between VFRs and FBRs, with FBRs being statistically more effective at maintaining lower arch alignment, but the difference was not clinically significant. REGISTRATION: PROSPERO registration (CRD42024518433).

Gingival health and relapse tendency: a split mouth randomized controlled trial of two positions of lower fixed retainers.

OBJECTIVE: To compare between lower permanent retainers placed in the middle of the incisal third and retainers placed in the middle of lower incisors in terms of gingival condition, lower incisors stability and retainers' failure rate. MATERIALS AND METHODS: This is a split-mouth clinical trial. Fifty patients finished fixed orthodontic treatment and required fixed permanent retainer in the lower arch were recruited. A multistranded (0.0215 inch) retainer, with a vertical step in the midline placing half of the retainer in the incisal third and the other half in the middle of the lower incisors was attached to all the teeth in the lower labial segment. After one year, all the subjects were recalled. The primary outcome was to evaluate the plaque index (PI) and the gingival index (GI) of the lower labial segment teeth. The secondary outcome was to assess retainers' failure rate and the relapse in lower labial segment alignment. RESULTS: The GI and the PI scores were significantly smaller on the side where the retainer was placed incisally (P = 0.004, P < 0.001, respectively). There was no statistical difference in the average Irregularity Index (IRI) and the retainer's failure rate between the two sides (P = 0.52, P = 0.76, respectively). CONCLUSION: Placing lower fixed retainers in the incisal third will improve the lower labial segment oral hygiene and gingival health in the lingual area without affecting the efficiency or the integrity of the retainers. This trial was not registered Null Hypothesis: Placing the lower permanent retainer in the middle of the lingual surfaces of the lower labial segment' teeth or in the incisal third will not affect the gingival health of the lower incisors.

Assessment of the unwanted tooth movement associated with an extended maxillary fixed retainer (3D analysis).

BACKGROUND: Posttreatment changes after orthodontic treatment are challenging. One of the main reasons for such a phenomenon is the lack of patient compliance with removable retainers especially in the maxillary arch, due to palatal coverage, deterioration of speech, decreased masticatory efficiency, and loss of retainers. Fixed retainers have been introduced to overcome patient compliance and provide longer stable results. However, teeth still show movements when a six-unit fixed retainer is in place. Thus, in this study, an eight-unit fixed retainer was evaluated in an attempt to eliminate unwanted movements. THE AIM OF THIS RESEARCH: was to assess short-term positional changes associated with an eight-unit extended maxillary fixed retainer. MATERIALS AND METHODS: A single-arm clinical trial was conducted to address the aim of the study. This research was approved by the institutional review board of the Faculty of Dentistry, Alexandria University (IORG:0008839, No-0479-8/2022). The registration date of this study was 5/06/2023. Twenty-eight patients (19.8 ± 4.5 years) who had finished the active orthodontic phase and started retention had an eight-unit extended maxillary fixed retainer that was bonded to the palatal surface of the maxillary incisors, canines, and the first premolars or the second premolars. Pre-retention and one-year post-retention intra-oral scans were made to produce STL files that were superimposed to determine the amount of tooth change. Additionally, analysis of digital casts and lateral cephalometric radiographs was performed. RESULTS: Statistically significant changes in all planes and the rotation of teeth after one year of retention were found. The upper right lateral incisor exhibited the most evident change in the vertical plane, while the upper right central incisor exhibited the greatest change overall. Minimal changes in the cast measurements were observed. Lateral cephalometric measurements showed minimal changes after one year of retention, and these changes were not statistically significant except in the interincisal angle and the angle between the upper incisor and the line connecting the A-point to the pogonion. CONCLUSION: Increasing the extension of maxillary fixed retainers did not eliminate unwanted tooth movement in the first year of retention.

Comparison of chairside rectangular chain retainers and multi-stranded conventional retainers: a randomized controlled trial.

BACKGROUND: While retention appliances are widely used in orthodontics, there is still no evidence-based consensus regarding the optimal type of appliance or time of retention. OBJECTIVES: To compare chairside rectangular chain retainers, which can be placed in one sitting, with conventional multi-stranded bonded retainers regarding their levels of stability, biological side effects, complications, and patient experiences. TRIAL DESIGN: A single-centre, two-arm, parallel-group randomized controlled trial. METHODS: In total, 48 patients were included in this single-centre, randomized controlled trial conducted in Varberg, Region Halland, Sweden. The patients were randomized to two groups: the chairside rectangular chain retainer group, using the Ortho FlexTech retainer (OFT); and the conventional retainer group, using the 0.0195 Penta One multi-stranded spiral wire (PeO). The primary outcome was Little´s irregularity index (LII) evaluated at debond (T0) and at 3 months (T3) and 12 months (T12). The secondary outcomes were inter-canine distance (ICD), plaque index (PI), calculus index (CI), bleeding on probing (BoP), and caries, evaluated at T0, T3, and T12, as well as patients' perceptions, evaluated at T3 and T12, and technical complications that were registered throughout the study period. The Mann-Whitney U-test was used for continuous variables for inter-group comparisons, and the Wilcoxon Signed Rank test was used for intra-group comparisons. RESULTS: There were no statistically significant differences between the groups regarding LII, biological side effects, technical complications, or patients' experiences. However, there was a small but statistically significant difference between the groups regarding the maintenance of the ICD. Within the OFT group, there was a significant increase in CI, and within the PeO group, there was a significant increase in BoP. CONCLUSIONS: In terms of clinical relevance, the chairside rectangular chain retainer and the conventional multi-stranded spiral wire provide similar outcomes with respect to the stability of alignment, biological side-effects, technical complications, and patients' experiences short-term. TRIAL REGISTRATION: VGFOUreg-929962. Keywords: Orthodontic retainers; fixed retainers; retention; stability.

What are the prevalence and risk factors associated with wire syndrome in dental students? A cross-sectional study.

INTRODUCTION: Wire syndrome (WS) refers to dental displacements that can be described as aberrant, inaccurate, unexplained, or excessive, on teeth still contained by an intact bonded retainer, without detachment or fracture, leading to evolving dental and periodontal, aesthetic and/or functional consequences. The objective of this study was to define the prevalence rate of mandibular WS and the associated risk factors. METHODS: Participants were dental students who had undergone orthodontic treatment and were wearing an intact fixed mandibular retainer. They completed a 20-item questionnaire, after which an extraoral and intraoral clinical examination was conducted. Participants were assigned to either the non-wire syndrome group or the wire syndrome group by two independent practitioners. Univariate and multivariate logistic regression models were used to investigate potential risk factors. RESULTS: A total of 59 students (23.4years±1.7years) were included. Among these, 9 students presented with mandibular WS, resulting in a prevalence rate of 15.25% (95% CI: 6.08%-24.43%). Univariate analysis revealed a significant association between a deep labio-mental fold, a concave profile, and a multi-strand round wire, and an excess risk of WS. The odds ratios were 16.5 (95% CI: 1.9-146.8, P=0.01), 6.4 (95% CI: 1.0-41.0, P=0.05), and 9.0 (95% CI: 1.7-48.7, P=0.01), respectively. Multivariate analysis confirmed these significant associations, except for the concave profile. CONCLUSIONS: The prevalence rate of wire syndrome was 15.25%. Two risk factors associated with WS were identified: a deep labio-mental fold and a multi-strand round wire retainer.

Comparison of speech changes caused by four different orthodontic retainers: a crossover randomized clinical trial.

OBJECTIVE: This study aimed to compare the influence of four different maxillary removable orthodontic retainers on speech. MATERIAL AND METHODS: Eligibility criteria for sample selection were: 20-40-year subjects with acceptable occlusion, native speakers of Portuguese. The volunteers (n=21) were divided in four groups randomized with a 1:1:1:1 allocation ratio. The four groups used, in random order, the four types of retainers full-time for 21 days each, with a washout period of 7-days. The removable maxillary retainers were: conventional wraparound, wraparound with an anterior hole, U-shaped wraparound, and thermoplastic retainer. Three volunteers were excluded. The final sample comprised 18 subjects (11 male; 7 female) with mean age of 27.08 years (SD=4.65). The speech evaluation was performed in vocal excerpts recordings made before, immediately after, and 21 days after the installation of each retainer, with auditory-perceptual and acoustic analysis of formant frequencies F1 and F2 of the vowels. Repeated measures ANOVA and Friedman with Tukey tests were used for statistical comparison. RESULTS: Speech changes increased immediately after conventional wraparound and thermoplastic retainer installation, and reduced after 21 days, but not to normal levels. However, this increase was statistically significant only for the wraparound with anterior hole and the thermoplastic retainer. Formant frequencies of vowels were altered at initial time, and the changes remained in conventional, U-shaped and thermoplastic appliances after three weeks. CONCLUSIONS: The thermoplastic retainer was more harmful to the speech than wraparound appliances. The conventional and U-shaped retainers interfered less in speech. The three-week period was not sufficient for speech adaptation.

Mechanical properties of combined packable and high-filled flowable composite used for the fixed retainer: an in vitro study.

BACKGROUND: Clinicians often utilize both flowable and packable composites concurrently in bonding fixed retainers. Thus, this study aimed to assess the synergistic effect of these composites in the bonding process. METHODS: This in vitro study divided specimens into three groups: flowable composite (nano-hybrid, Tetric N-Flow, Ivoclar Vivadent), packable composite (nano-hybrid, Tetric N-ceram, Ivoclar Vivadent), and combined use of flowable and packable composite. Shear bond strength (SBS), adhesive remnant index (ARI), and wire pull-out resistance were compared among the groups. Statistical analyses were conducted using ANOVA and Tukey tests to compare study groups. Additionally, Chi-square and Kruskal-Wallis tests were employed to analyze the ARI index among the groups. RESULTS: ANOVA results indicated no statistically significant differences among test groups (P = 0.129) regarding SBS. However, a significant difference existed between flowable and packable composite groups (P = 0.01) regarding ARI scores. Among the study groups, flowable composite exhibited the highest frequencies of ARI scores of 1 and 2, whereas packable composite showed the highest frequency of ARI scores of 0. The combined group had higher frequencies of ARI scores of 0 and 1 compared to the flowable composite. The wire pull-out test revealed that the combined application of flowable and packable composite resulted in significantly lower detachments compared to the packable composite alone (P = 0.008). However, no significant differences were observed in the comparisons between the flowable-packable (P = 0.522) and combined-flowable (P = 0.128) groups. CONCLUSION: The combined use of flowable and packable composites for fixed retainers demonstrated adequate shear bond strength and ideal ARI scores, suggesting it as a suitable adhesive system for bonding orthodontic fixed retainers.

Three-dimensional assessment of virtual clear aligner attachment removal: A prospective clinical study.

INTRODUCTION: In digital dentistry, virtual attachment removal (VAR) optimizes clear aligner therapy by enhancing efficiency for refinements and enabling prefabricated retainer production through the removal of attachments from a digital scan before the clinical removal of clear aligner attachments. This prospective clinical study aimed to evaluate the accuracy of VAR in the maxillary arch. METHODS: A total of 110 teeth were analyzed from a sample of 54 maxillary scans from 25 subjects. Models with attachments were virtually debonded using Meshmixer (Autodesk, San Rafael, Calif) and superimposed over the control group in MeshLab. Vector Analysis Module (Canfield Scientific, Fairfield, NJ) was used to calculate and analyze 3-dimensional Euclidean distances on the buccal surfaces between the superimposed models. Statistical analysis was performed using SPSS (version 23.0, IBM, Armonk, NY). The Shapiro-Wilkes (α = 0.05) test determined a nonnormal distribution of results. The Kruskal-Wallis (α = 0.05) was used to determine differences between different tooth types and the number of attachments. RESULTS: The VAR protocol showed no statistical differences in the root mean square between different tooth segments with an overall tendency for inadequate attachment removal. No difference between the groups was found regarding the number of attachments when used as a main factor. CONCLUSIONS: The VAR technique is precise enough for the fabrication of retainers from printed dental models in a clinical setting and is not affected by the number of attachments on the tooth.

An in vitro comparison of the dimensional stability of four 3D-printed models under various storage conditions.

OBJECTIVES: To investigate the dimensional stability of various 3D-printed models derived from resin and plant-based, biodegradable plastics (PLA) under specific storage conditions for a period of up to 21 weeks. MATERIALS AND METHODS: Four different printing materials, including Draft V2, study model 2, and Ortho model OD01 resins as well as PLA mineral, were evaluated over a 21-week period. Eighty 3D-printed models were divided equally into two groups, with one group stored in darkness and the other exposed to daylight. All models were stored at a constant room temperature (20°C). Measurements were taken at 7-week intervals using the Inspect 3D module in OnyxCeph software (Image Instruments GmbH, Chemnitz, Germany). RESULTS: Dimensional change was noted for all of the models with shrinkage of up to 0.26 mm over the study period. Most contraction occured from baseline to T1, although significant further contraction also arose from T1 to T2 (P < .001) and T1 to T3 (P < .001). More shrinkage was observed when exposed to daylight overall and for each resin type (P < .01). The least shrinkage was noted with Ortho model OD01 resin (0.16 mm, SD = 0.06), and the highest level of shrinkage was observed for Draft V2 resin (0.23 mm, SD = 0.06; P < .001). CONCLUSIONS: Shrinkage of 3D-printed models is pervasive, arising regardless of the material used (PLA or resin) and being independent of the brand or storage conditions. Consequently, immediate utilization of 3D printing for orthodontic appliance purposes may be preferable, with prolonged storage risking the manufacture of inaccurate orthodontic retainers and appliances.

Impact of fixed orthodontic retainers on oral health-related quality of life: a longitudinal prospective study.

OBJECTIVE: The aim of the present study was to assess the impact of orthodontic retainers on oral health-related quality of life (OHRQoL) in the short and long terms after orthodontic treatment. METHODS: Data from 45 patients up to three years after orthodontic treatment (T0) were analyzed. Patients were reassessed four years (T1) after T0. OHRQoL was measured using the OHIP-14 (Oral Health Impact Profile-14) questionnaire. The presence of a fixed retainer in the upper and/or lower arches, sex, and age were the predictive variables evaluated at T0 and T1. The occurrence of retainer fracture at T0 was clinically evaluated. Due to the COVID-19 pandemic, clinical examination on T1 was not possible, so the OHIP-14 and the self-perception of changes in teeth position and fracture of retainers were examined using an on-line questionnaire. RESULTS: At the initial examination, the presence of upper retainers had a negative impact on quality of life (p=0.018). The OHIP-14 value increased significantly from T0 to T1 (p=0.014), regardless of the presence of retainers. The fracture or debonding of the retainer reported by the patient was the only variable that had a negative impact on OHRQoL (p=0.05). CONCLUSION: The use of fixed upper retainers suggests a negative impact on the quality of life of the orthodontic patient after the end of orthodontic treatment. This impact, however, is negligible in the long term, except when associated with fracture or debonding. This study emphasizes the need for continuous follow-up of orthodontic patients during the retention period.