Sociomedical and oral factors affecting masticatory performance in an older population.

OBJECTIVES: To assess the sociomedical and oral factors affecting masticatory performance in a community-dwelling older population. MATERIALS AND METHODS: Community-dwelling persons over 60 years were investigated using medical and dental oral interviews, oral and denture examination (natural teeth, tooth mobility, number of occluding tooth pairs, and removable dentures' prevalence and quality), and evaluation of masticatory performance using a mixing ability test. RESULTS: A total of 130 participants with a mean age of 73.9±8.5 years were recorded. Fifty-eight (44.6%) used various types of removable prostheses. Twenty were edentulous and used a pair of complete dentures. Univariate analyses revealed statistically significant associations (p≤0.05) between masticatory performance and aging, marital status, subjective chewing ability, use of removable dentures, use of various combinations of complete dentures, pain caused by maxillary denture, number of teeth, tooth mobility, posterior chewing pairs, all chewing contacts natural or prosthetic, retention of mandibular partial dentures, and dentures' occlusion. The multivariable quantile regression analysis revealed that fewer natural teeth (95% CI: -0.02-0.01, p<0.001), being edentulous and using a pair of complete dentures (95% CI: 0.09-0.35, p=0.001), and larger percentage of severely mobile teeth (95% CI: 0.07-0.82, p=0.020) were associated with lower masticatory performance. CONCLUSIONS: Poor masticatory performance in older adults was associated with fewer teeth, being edentulous and using a pair of complete dentures, and increased prevalence of severe tooth mobility. CLINICAL RELEVANCE: Retaining the natural dentition and preventing and treating periodontal disease are important measures to maintain masticatory performance in older adults.

Socio-behavioral factors, oral hygiene level and periodontitis prevalence in a 35-44-year-old Greek adult population: A cross-sectional survey.

BACKGROUND: Sub-optimal oral hygiene is considered as a primary risk factor for periodontitis occurrence. Various socio-behavioral determinants may contribute either independently or by influencing adversely the oral hygiene (OH) level. The aim of the present study was to examine the periodontal status of 35-44-year-old Greek adults and determine the contribution of risk indicators, including the socio-behavioral aspects and the population's oral hygiene level, on disease prevalence. MATERIAL AND METHODS: In 1218 participants, Community Periodontal Index (CPI), Loss of Attachment (LoA) and simplified Oral Hygiene Index (OHI-S) were calculated. Multivariable regression models examined the effect of socio-behavioral factors with/without the inclusion of OHI-S level on pocket depth (PD)≥4mm and LoA≥4mm presence. RESULTS: 11.8% of the participants had healthy periodontium, whereas 37.3% and 5.6% presented with shallow and deep pocketing, respectively. 60.4%, 28.8%, and 10.8.% of the adults demonstrated LoA≤3mm, 4-5mm, and ≥6mm, accordingly. Fair and poor oral hygiene significantly increased the likelihood for PD≥4mm (OR=4.8-20.3) and LoA≥4mm (OR=3.3-6.0) presence. 'Emergency-oriented dental visiting pattern' significantly elevated the chance for PD≥4mm presence (OR=1.7). 'Lower education level' 'urban location', and 'using an interdental brush' were significantly independently linked to LoA≥4mm occurrence (OR=1.7-2.1, 1.5, and 2.0, respectively). Lower educated individuals demonstrated inferior oral hygiene status, which in turn elevated significantly the chances of PD≥4mm presence. Smoking more than 10 cigarettes/day, emergency-oriented dental attendance pattern and not flossing were linked to worse oral hygiene levels, which consequently increased significantly the likelihood of LoA≥4mm occurrence. CONCLUSIONS: Fair and poor oral hygiene contribute strongly to periodontitis occurrence. Various socio-behavioral factors may influence adversely oral hygiene maintenance, leading to periodontitis manifestations. Key words:Community periodontal index, periodontal attachment loss, oral hygiene, adults 35-44, cross-sectional survey, socio-behavioral indicators.

Oral factors and adherence to Mediterranean diet in an older Greek population.

PURPOSE: The aim of this study was to investigate the effect of oral factors on adherence to the Mediterranean diet in an older population METHODS: 130 persons over 60 years visiting Open Care Community Centers for Older People participated in this study. Oral interviews recorded demographic and sociomedical information, subjective oral complaints, and dental habits. Adherence to Mediterranean diet was assessed using the MDI_BNC4H index (range: 0-14). An oral examination was performed, and evaluation of the masticatory performance was carried out using a two-color chewing gum that was digitally analysed. RESULTS: The mean age of the study participants was 73.9 ± 8.5 years. The score of adherence to the Mediterranean diet ranged from 3 to 9 (5.6 ± 1.4). 58 participants used removable prostheses, while 20 used a pair of complete dentures. Univariate analyses revealed that the parameters that negatively significantly, or marginally significantly, affected the level of adherence to the Mediterranean diet were lower masticatory performance (p = 0.050), larger number of drugs per day (p = 0.056), higher BMI (p = 0.043) and smoking (p = 0.053). The multivariable analysis revealed that lower adherence to the Mediterranean diet was significantly associated with higher BMI (p = 0.047) and lower masticatory performance (p = 0.050). CONCLUSIONS: Increased masticatory performance was an independent predictor of better adherence to the Mediterranean diet in an older population.

Caries prevalence and caries experience (ICDAS II criteria) of 5-, 12- and 15-year-old Greek children in relation to socio-demographic risk indicators. Trends at the national level in a period of a decade.

PURPOSE: To study the caries status of 5, 12 and 15-year-old Greek children, assess how disease parameters are related to socio-demographic indicators and identify relevant trends at the national level. METHODS: A stratified cluster sample of 3702 children in total was randomly selected and examined clinically for caries (ICDAS II criteria). Caries experience was outlined by adapting ICDAS0-6 criteria to the d/D component of the WHO dmf/DMF index configuration. Percentages (%) of caries experience-free children, of children with initial caries (ICDAS1-2), and the mean d1-2t/D1-2T, d3-6mft/D3-6MFT and d3-6mfs/D3-6MFS indices were calculated. The probability of presenting with d1-2t/D1-2T ≥ 1 was assessed by binary logistic regression analysis, whereas negative binomial regression models examined the effect of socio-demographic parameters on d3-6mfs/D3-6MFS indices (level of significance: p ≤ 0.05). RESULTS: 60.1%, 48.1%, and 34.7% of the 5, 12, and 15-year-old children, respectively, had no caries experience at the defect level (d3-6mft/D3-6MFT = 0). Initial lesions (ICDAS1-2) were detected in 17.7%, 19.3% and 17.4% of the 5, 12 and 15-year-olds, accordingly. Mean d1-2t/D1-2T was 0.93, 1.70, and 2.51, whereas mean d3-6mft/D3-6MFT was 1.48, 1.61, and 2.46 for the 5, 12, and 15-year-olds, respectively. Children with higher educated parents and 15-year-old urban residents exhibited significantly less caries experience at the defect level. Initial caries lesions presented a significantly higher probability of being detected in urban-residing 5- and 15-year-olds, while no consistent trend could be identified for parental education level. Caries prevalence and experience levels declined for all age groups in ten years. CONCLUSION: Although the dental health of Greek children has improved disparities remain, calling for organised primary and secondary preventive interventions.

Dental Caries Prevalence and Experience (ICDAS II Criteria) of 5-, 12- and 15-Year-Old Children and Adolescents with an Immigrant Background in Greece, Compared with the Host Population: A Cross-Sectional Study.

Evidence regarding disparities in oral health among native and immigrant child and adolescent populations in Europe is scarce. The present study aimed to determine the caries status of 5-, 12-, and 15-year-olds with an immigrant background in Greece in relation to their sociodemographic characteristics and compare their caries levels with those of their native Greek peers. A sample of 707 immigrants underwent clinical examination for caries (ICDAS II criteria), followed by a calculation of caries prevalence and experience estimates (2013-2014). Multivariable regression models assessed the effect of ethnic background on the caries experience (d3-6mfs/D3-6MFS) of the total (707 immigrants and 3702 Greeks) population, and the association between parental education level and the immigrants' d3-6mfs/D3-6MFS. Among the 5- and 12-year-olds, those with an immigrant background demonstrated higher caries rates and had unfulfilled treatment needs at higher proportions. Among 15-year-old adolescents, no considerable differences in caries status were observed according to ethnic background (native Greek or immigrant). The strength of the association between immigrant background and caries experience levels attenuated gradually with increasing age (IRR = 1.61, 1.27 and 1.10, and p = 0.001, p = 0.006 and p = 0.331 for 5-, 12- and 15-year-olds, respectively). Among the immigrants, adolescents with less educated mothers exhibited elevated caries levels. Public health strategies should prioritize immigrant children and early adolescents in order to reduce the existing ethnic disparities in oral health.

Development of a Greek Oral health literacy measurement instrument: GROHL.

BACKGROUND: Oral health literacy is an important construct for both clinical and public health outcomes research. The need to quantify and test OHL has led to the development of measurement instruments and has generated a substantial body of recent literature. A commonly used OHL instrument is REALD-30, a word recognition scale that has been adapted for use in several languages. The objective of this study was the development and testing of the Greek language oral health literacy measurement instrument (GROHL). METHODS: Data from 282 adult patients of two private dental clinics in Athens, Greece were collected via in-person interviews. Forty-four words were initially considered and tested for inclusion. Item response theory analysis (IRT) and 2-parameter logistic models assessing difficulty and discriminatory ability were used to identify an optimal scale composition. Internal consistency was examined using Cronbach's alpha and test-retest reliability was measured using intraclass correlation coefficient (ICC) in a subset of 20 participants over a two-week period. Convergent validity was tested against functional health literacy screening (HLS) items, dental knowledge (DK), oral health behaviors (OHBs), oral health-related quality of life (OHRQoL; OHIP-14 index), as well as self-reported oral and general health status. RESULTS: From an initial item pool of 44 items that were carried forward to IRT, 12 were excluded due to no or little variance, 10 were excluded due to low item-test correlation, and 2 due to insignificant contribution to the scale, i.e., difficulty parameter estimate with p > 0.05. The twenty remaining items composed the final index which showed favorable internal consistency (alpha = 0.80) and test-retest reliability (ICC = 0.95). The summary score distribution did not depart from normality (p = 0.32; mean = 11.5; median = 12; range = 1-20). GROHL scores were positively correlated with favorable oral hygiene behaviors and dental attendance, as well as HLS, DK and education level. CONCLUSION: The GROHL demonstrated good psychometric properties and can be used for outcomes research in clinical and public health settings.

Pediatricians' awareness on orthodontic problems and related conditions-a national survey.

BACKGROUND: Correction of dentofacial deformities via orthodontics is an integral part of oral health as promotes optimal function, periodontal health, aesthetics and overall oral health-related quality of life. The aim of this study was to examine whether paediatricians examine their patients to orthodontists, whether they have sufficient knowledge in basic orthodontic principles and whether they refer their patients for orthodontic abnormalities. RESULTS: We conducted a survey study of paediatricians in Greece. Questionnaires were completed by 96 out of 123 paediatricians (response rate 78%). In the assessment of the examination of the oral cavity, a low frequency of examination of the position of the teeth (54%) and jaws (51%) was found. Reasons paediatricians referred patients to specialists varied from mouth breathing-snoring 24% (23/96) to face or teeth asymmetry 87% (84/96). In the multivariable analyses for the effect of gender, work sector or years of experience in the decision for orthodontic referral, we could not identify any significant predictors. CONCLUSIONS: The results of this study indicate that there was variability regarding orthodontic knowledge among paediatricians. Although the majority were aware of the importance of examination of the oral cavity, they did not have the appropriate knowledge to perform a full and systematic screening for orthodontic problems. The probability of referral was different for the various orthodontic anomalies.

Late effects of chemo and radiation treatment on dental structures of childhood cancer survivors. A systematic review and meta-analysis.

BACKGROUND: This systematic review summarizes the prevalence of dental defects after chemo and radiation therapy and correlates the findings with specific characteristics of each treatment modality. METHODS: Database search was performed for studies reporting dental late effects of chemo and radiation therapy. After data extraction and risk of bias assessment, prevalence of crown and root defects was assessed. Correlations between each defect and the characteristics of the antineoplastic treatment were performed. RESULTS: Sixteen nonrandomized studies were included, yielding a total of 1300 patients with a mean age at diagnosis of 4.5 years. Results reported that root defects were more common than crown defects. The most common root defect was impaired root growth and microdontia the most common crown defect. Age, radiation dose and field were statistically associated with higher prevalence of dental defects. CONCLUSION: Defects were associated with combination of chemotherapy and radiotherapy, as used in current therapeutic antineoplastic modalities.

Outcome reporting discrepancies between trial entries and published final reports of orthodontic randomized controlled trials.

BACKGROUND/OBJECTIVES: The aim of this study was to identify outcome-related discrepancies between registry trial entries and final published reports in orthodontic randomized controlled trials (RCTs). The percentage of registered orthodontic RCTs was also recorded. MATERIALS/METHOD: Five trial registries, ClinicalTrials.gov (https://clinicaltrials.gov/), International Standard Randomised Controlled Trial Number registry (http://www.isrctn.com/), European Union Clinical Trials Register (https://www.clinicaltrialsregister.eu/), Australia New Zealand Clinical Trials Registry (http://www.anzctr.org.au/) and Clinical Trials Registry of India (www.ctri.nic.in/) were searched up to April 2018 in order to identify completed orthodontic RCTs. The unique trial identifier, the title and authors name were used to search for publications based on entries within Google (https://www.google.com), Google Scholar (https://scholar.google.gr/) and MEDLINE via PubMed (https://www.ncbi.nlm.nih.gov/pubmed/). Outcome reporting discrepancies and a number of other entry/publication characteristics were recorded including timing of registration, type of journal/publication, significance of the primary outcome in the final report. The number of trials registered among the total number of published RCTs in orthodontics was recorded within the time span assessed. RESULTS: One hundred and twenty-four entries were identified for completed orthodontic RCTs, whereas 53 of those were related to published final reports. Outcome reporting discrepancies were ascertained for 47 per cent of publications (n = 2 5); discrepancies were more prevalent for non-primary outcomes (n = 21, 40 per cent). Only 16 per cent of the published orthodontic RCTs had been registered. LIMITATIONS: Only a subset of trial entries were assessed as these were related to publication records. CONCLUSIONS/IMPLICATIONS: Registration of clinical trials in orthodontics remains far from universal. A significant level of outcome reporting discrepancy was observed within this subset of registered trials.

The short-term effects of television advertisements of cariogenic foods on children's dietary choices.

OBJECTIVE: To investigate the short-term influence of the advertising of cariogenic foods on children's dietary preferences, and the possible moderating effect of several factors on this influence. METHODS: One-hundred and eighty-three children, 11-12 years of age, were exposed to advertisements showing sugary food and non-food items, in a within-subject counterbalanced design. Their preferences for unhealthy and healthy foods, and their ability to recall or recognise the advertisements, were measured following both sessions. Information on their dietary habits, leisure activities and sociodemographic details were obtained through a questionnaire completed by their parents. Their decayed, missing and filled teeth (DMFT) index, body weight and height were also recorded. A generalised linear mixed model was used to examine the differences in food preferences between experimental conditions, and the associations between children's preferences and the other factors assessed. RESULTS: Exposure to food advertisements significantly decreased the selection of healthy foods. Children with a higher DMFT index chose a higher percentage of unhealthy foods, and children who spent more time watching television chose an increased number of healthy foods, after their exposure to food advertisements. Regardless of condition, girls selected fewer foods than boys. Children with a higher DMFT index selected more unhealthy foods than children with a lower DMFT index. Obese children chose an increased number of healthy foods than those who were overweight and normal weight. CONCLUSIONS: Food advertisements can divert, for a short time, children's preference over healthy food choices, and could lead to changes in their eating habits, which may put them at higher risk of dental diseases and obesity.

Statistical analysis in orthodontic journals: are we ignoring confounding?

AIM: To assess the prevalence of adjustment for confounding within statistical analysis and matching at the design stage in leading orthodontic journals and to explore potential associations between accounting for confounding and publication characteristics. MATERIALS AND METHODS: Twenty-four issues of four leading orthodontic journals with the highest impact factor were searched from July 2014 backwards. Confounding adjustment through statistical analysis and study characteristics including journal, study design, region of origin, number of authors, number of centres, involvement of a statistician, significance of results, and type of analysis were recorded. Reporting of matching at the design stage was also recorded. RESULTS: Of 426 studies identified, only 71 (17 per cent) accounted for confounding in the statistical analysis. There was evidence that journal, country of authorship, and involvement of a statistician (odds ratio = 3.91, 95 per cent confidence interval: 2.16-7.10; P < 0.001) were significant predictors of accounting for confounding at the analysis level. Reporting of matching at the design stage was identified in 111 of 426 (26 per cent) studies in which 9 studies adjusted for confounding at the analysis level. CONCLUSIONS: Appropriate adjustment for confounding in orthodontic literature either at the design or at the analysis stage was identified in less than half of studies overall (41 per cent), suggesting lack of expertise and awareness in design, conduct, analysis, and reporting of non-randomized studies in this field. This is a critical limitation that can potentially result in biased estimates and associations between examined exposures and outcomes.

Randomized and nonrandomized studies: complementary or competing?

Both randomized and nonrandomized studies are integral to orthodontic research and practice because they permit evaluation of relationships between exposures and outcomes, allowing the efficacy, effectiveness, and safety of interventions to be assessed. These designs allow clinical decisions to be informed. Nonrandomized designs include nonrandomized clinical trials, cohort studies, case-control studies, cross-sectional studies, case series, and ecological studies. There is debate surrounding the optimal research design; however, both randomized and nonrandomized designs are important to build a broad, informative evidence base. The designs are therefore complementary, with unique advantages and limitations. The applicability of either approach hinges on the clinical question posed, the feasibility of studying it, and ethical considerations.

The reporting quality of meta-analysis results of systematic review abstracts in periodontology and implant dentistry is suboptimal.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Assessment of the quality of reporting in abstracts of systematic reviews with meta-analyses in periodontology and implant dentistry. Faggion CM Jr., Liu J, Huda F, Atieh M. J Periodontal Res 2014; 49(2):137-42. REVIEWER: Argy Polychronopoulou, DDS, MS, ScM, ScD PURPOSE/QUESTION: What is the reporting quality of meta-analysis results of abstracts of systematic reviews in periodontology and implant dentistry journals? SOURCE OF FUNDING: The authors received no funding for this study TYPE OF STUDY/DESIGN: Meta-epidemiological study LEVEL OF EVIDENCE: Level 3: Other evidence STRENGTH OF RECOMMENDATION GRADE: Not applicable.

Developing evidence-based dentistry skills: how to interpret randomized clinical trials and systematic reviews.

Decision-making based on reliable evidence is more likely to lead to effective and efficient treatments. Evidence-based dentistry was developed, similarly to evidence-based medicine, to help clinicians apply current and valid research findings into their own clinical practice. Interpreting and appraising the literature is fundamental and involves the development of evidence-based dentistry (EBD) skills. Systematic reviews (SRs) of randomized controlled trials (RCTs) are considered to be evidence of the highest level in evaluating the effectiveness of interventions. Furthermore, the assessment of the report of a RCT, as well as a SR, can lead to an estimation of how the study was designed and conducted.

Assessing the reporting quality in abstracts of randomized controlled trials in leading journals of oral implantology.

AIM: Abstracts of randomized clinical trials are extremely important as trial appraisal is often based on the information included here. The objective of this study was to assess the quality of the reporting of RCT abstracts in journals of Oral Implantology. MATERIAL AND METHODS: Six leading Implantology journals were screened for RCTs between years 2008 and 2012. A 21-item modified CONSORT for abstracts checklist was used to examine the completeness of abstract reporting. Descriptive statistics and linear regression modeling were employed for data analysis. RESULTS: One hundred and sixty three RCT abstracts were included in this study. The majority of the RCTs were published in the Clinical Oral Implants Research (42.9%). The mean overall reporting quality score was 58.6% (95% CI: 57.6-59.7). The highest score was noted in the European Journal of Oral Implantology (63.8%; 95% CI: 61.8-65.8). Multivariate analysis demonstrated that abstract quality score was related to publication journal and number of research centers involved. Most abstracts adequately reported interventions (89.0%), objectives (77.9%) and conclusions (74.8%) while failed to report randomization procedures, allocation concealment, effect estimate, confidence intervals, and funding. Registration of RCTs was not reported in any of the abstracts. CONCLUSIONS: The reporting quality in abstracts of RCTs published in Oral Implantology journals needs to be improved. Editors and authors should be encouraged to endorse the CONSORT for abstracts guidelines in order to achieve optimal quality in abstract reporting.

Extracurricular factors influence perceived stress in a large cohort of Colombian dental students.

The aim of this study was to investigate the association of extracurricular factors including socioeconomic status and career choice with perceived stress in dental school in a large cohort of Colombian dental students. Participants in the study were 5,700 students enrolled in seventeen Colombian dental schools. The study employed a Spanish adaptation of the Dental Environment Stressors (DES30-Sp) questionnaire and recorded an array of demographic, socioeconomic, career choice, and dental studies-related information. Data analyses relied on descriptive, bivariate, and multivariate methods based on multi-level mixed-effects linear regression and post hoc estimation of predictive margins. "Fear of failing a course or year" emerged as the highest ranked item. Male students consistently reported less perceived stress than females, and stress scores were higher among seniors. Independent of gender, age, and study year, having dentistry as one's first career choice, relying on financial support, and belonging to higher socioeconomic strata were associated with lower stress levels. Academic environment interventions aimed to improve students' educational well-being will need to account for the individual heterogeneity among them. These data from a robust cohort of predoctoral dental students underscore the importance of considering students' educational experiences in a broader social and economic context.

Factorial designs: an overview with applications to orthodontic clinical trials.

Factorial designs for clinical trials are often encountered in medical, dental, and orthodontic research. Factorial designs assess two or more interventions simultaneously and the main advantage of this design is its efficiency in terms of sample size as more than one intervention may be assessed on the same participants. However, the factorial design is efficient only under the assumption of no interaction (no effect modification) between the treatments under investigation and, therefore, this should be considered at the design stage. Conversely, the factorial study design may also be used for the purpose of detecting an interaction between two interventions if the study is powered accordingly. However, a factorial design powered to detect an interaction has no advantage in terms of the required sample size compared to a multi-arm parallel trial for assessing more than one intervention. It is the purpose of this article to highlight the methodological issues that should be considered when planning, analysing, and reporting the simplest form of this design, which is the 2 × 2 factorial design. An example from the field of orthodontics using two parameters (bracket type and wire type) on maxillary incisor torque loss will be utilized in order to explain the design requirements, the advantages and disadvantages of this design, and its application in orthodontic research.

Reporting quality of systematic review abstracts in leading oral implantology journals.

OBJECTIVES: Abstracts of systematic reviews are of critical importance, as consumers of research often do not access the full text. This study aimed to assess the reporting quality of systematic review (SR) abstracts in leading oral implantology journals. METHODS: Six specialty journals were screened for SRs between 2008 and 2012. A 16-item checklist, based on the PRISMA statement, was used to examine the completeness of abstract reporting. RESULTS: Ninety-three SR abstracts were included in this study. The majority were published in Clinical Oral Implants Research (43%). The mean overall reporting quality score was 72.5% (95% CI: 70.8-74.2). Most abstracts were structured (97.9%), adequately reporting objectives (97.9%) and conclusions (93.6%). Conversely, inadequate reporting of methods of the study, background (79.6%), appraisal (65.6%), and data synthesis (65.6%) were observed. Registration of reviews was not reported in any of the included abstracts. Multivariate analysis revealed no difference in reporting quality with respect to continent, number of authors, or meta-analysis conduct. CONCLUSIONS: The results of this study suggest that the reporting quality of systematic review abstracts in implantology journals requires further improvement. CLINICAL SIGNIFICANCE: Better reporting of SR abstracts is particularly important in ensuring the reliability of research findings, ultimately promoting the practice of evidence-based dentistry. Optimal reporting of SR abstracts should be encouraged, preferably by endorsing the PRISMA for abstracts guidelines.

Survival of bonded lingual retainers with chemical or photo polymerization over a 2-year period: a single-center, randomized controlled clinical trial.

INTRODUCTION: The objective of this trial was to compare the survival rates of mandibular lingual retainers bonded with either chemically cured or light-cured adhesive after orthodontic treatment. METHODS: Patients having undergone orthodontic treatment at a private orthodontic office were randomly allocated to fixed retainers placed with chemically cured composite or light-cured composite. Eligibility criteria included no active caries, restorations, or fractures on the mandibular anterior teeth, and adequate oral hygiene. The main outcome was any type of first-time lingual retainer breakage; pattern of failure (adapted adhesive remnant index scores) was a secondary outcome. Randomization was accomplished with random permuted blocks of 20 patients with allocation concealed in sequentially numbered, opaque, sealed envelopes. Blinding was applicable for outcome assessment only. Patients were reviewed at 1, 3, and 6 months and then every 6 months after placement of the retainer until completion of the study. Data were analyzed using survival analysis including Cox regression; sensitivity analysis was carried out after data imputation for subjects lost to follow-up. RESULTS: Two hundred twenty patients (median age, 16 years; interquartile range, 2; range, 12-47 years) were randomized in a 1:1 ratio to either chemical or light curing. Baseline characteristics were similar between groups, the median follow-up period was 2.19 years (range, 0.003-3.64 years), and 16 patients were lost to follow-up. At a minimum follow-up of 2 years, 47 of 110 (42.7%) and 55 of 110 (50.0%) retainers had some type of failure with chemically cured and light-cured adhesive, respectively (log-rank test, P = 0.35). Data were analyzed on an intention-to-treat basis, and the hazard ratio (HR) was 1.15 (95% confidence interval [CI], 0.88-1.70; P = 0.47). There was weak evidence that age is a significant predictor for lingual retainer failures (HR, 0.96; 95% CI, 0.93-1.00; P = 0.08). Adhesive remnant index scoring was possible for only 66 of the 102 (64.7%) failures and did not differ between composites (Fisher exact test, P = 0.16). No serious harm was observed other than gingivitis associated with plaque accumulation. CONCLUSIONS: The results of this study indicated no evidence that survival of mandibular lingual retainers differs between chemically and light-cured adhesives. The overall failure rate was 46.4%; however, this included any type of failure, which may have exaggerated the overall failure rate.