Prevalence of temporomandibular disorders in clear aligner patients using orthodontic intermaxillary elastics assessed with diagnostic criteria for temporomandibular disorders (DC/TMD) axis II evaluation: A cross-sectional study.

BACKGROUND: The objective of this investigation is to assess the relationship between the utilisation of orthodontic intermaxillary elastics and temporomandibular disorder (TMD) symptoms in clear aligner patients and to examine the correlation between the elastic usage time with the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD)-Axis II Evaluation Forms. METHODS: This study was carried out on a total of 40 clear aligner patients using intermaxillary elastics in the experimental group and 30 clear aligner patients who did not use any intermaxillary elastics in the control group. The data were evaluated using the Mann-Whitney U, chi-square, Fisher's exact chi-square, and Fisher Freeman Halton exact chi-square tests. RESULTS: The characteristic pain intensity, mastication, mobility, communication, global and PHQ-9 scores of the experimental group were significantly higher than those of the control group (p < .05). The characteristic pain intensity score, interference score and chronic pain grade score of patients using Class III elastics were statistically significantly higher than those of patients using Class II elastics (p < .05). Patients who used elastics for less than 6 months had statistically significantly higher PHQ-9 scores than those who used elastics for more than 6 months (p < .05). CONCLUSIONS: Orthodontic treatment may affect occlusion, bite force and jaw movement, which may cause or worsen TMD symptoms, and the DC/TMD questionnaires can determine if orthodontic patients acquire TMD by assessing their psychosocial state and pain-related problems.

Comparison of sleep quality between clear aligner and fixed appliance orthodontic therapies.

BACKGROUND: Although available evidence suggests that orthodontic appliances can impact quality of life, there is limited information on the impact of orthodontic appliances on sleep quality. This study aimed to compare sleep quality between patients undergoing orthodontic treatments using conventional fixed appliances and clear aligners. METHODS: Adult patients attending clinics in Saudi Arabia participated in this cross-sectional study. Sleep quality was assessed using the validated Arabic version of the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Statistical significance was determined using inferential analysis, with a P < 0.05 considered statistically significant. RESULTS: There were 69 patients included in the study. The average age of a patient (33.12 ± 8.1) who received the clear aligner was significantly higher than those who received the fixed appliance (27.7 ± 5.9) (P < 0.05). The variation in the average score of ESS because of the education level was found to be statistically significant (P < 0.05). No significant difference was observed between the mean average ESS and PSQI global scores across the two orthodontic treatment groups. The average sleep latency scores were significantly higher in females than males when analyzing the PSQI component score across sex (P < 0.05). In education, ESS, PSQI global, habitual sleep efficiency, the use of sleep medication, and daytime dysfunction had a positive, weak, but significant correlation. CONCLUSIONS: Overall, this study concluded that regardless of the orthodontic appliances used, there was no statistically significant difference in sleep quality during the treatment.

Effect of oral exposure on chemical, physical, mechanical, and morphologic properties of clear orthodontic aligners

The dental industry is heavily committed to developing more esthetic solutions for orthodontic treatments. Invisalign is a system of transparent orthodontic aligners introduced as an alternative to conventional orthodontic fittings with brackets and metal wires. This study aimed to assess the chemical, physical, mechanical and morphologic changes in these polymeric aligners after exposure to the oral environment. Twenty-four Invisalign orthodontic aligners were equally divided into 2 groups: an in vivo aged group in which patients used aligners for 14 days and the reference group, unexposed to the oral environment. Different experimental techniques were used to study the chemical structure, the color changes and translucency, the density and subsequent volume of the aligners, mechanical properties, surface roughness, morphology and elemental composition. The data were subjected to several statistical analyses. Clear orthodontic aligners exhibit chemical stability but undergo a statistically significant optical change in color and translucency. There was a gradual increase in the water absorption rate and the dimensional variation of the polymer, indicating a strong correlation among these factors. The mechanical properties of the polymer showed a statistically significant decrease in its elastic modulus and hardness. There was a slight tendency toward increased surface roughness of the material, but no statistical differences were found between reference and aged groups. The surface morphology of the used aligners demonstrates microcracks, distortions and biofilm formation. Intraoral aging adversely affected the physical, mechanical, and morphologic properties of the Invisalign appliance.

Orthognathic surgery and aligners. A comparative assessment of periodontal health and quality of life in postsurgical orthodontic treatment with aligners versus traditional fixed appliances: a randomized controlled trial.

BACKGROUND: Removable clear aligners have become very popular in the last few decades, but they are still little used in the field of orthognathic surgery (OS). The objective of this study was to compare periodontal health and quality of life (QoL) associated to postsurgical orthodontic treatment. MATERIAL AND METHODS: Patients with dentofacial deformities undergoing OS were randomly allocated to receive postsurgical orthodontic treatment with either fixed orthodontic appliances or Invisalign. The main outcomes were periodontal health and QoL. Plaque index, probing depth and bleeding on probing were assessed as periodontal health indicators. QoL was assessed through the Orthognathic Quality of Life Questionnaire (OQLQ-22) and the Oral Health Impact Profile (OHIP-14). Data were analyzed before surgery and end of treatment. Total duration of treatment was also recorded. RESULTS: Twenty-eight patients were randomized, (16 women, 12 men). Periodontal assessment showed better outcomes for the Invisalign group: bleeding on probing (p=0.013), plaque index (p=0.001) and probing depth (p<0.001). The QoL questionnaires showed significant differences in favor of the Invisalign group: OHIP-14 (p=0.004) and OQLQ-22 (p=0.002). Total duration of treatment was similar in both groups (p=0.575). CONCLUSIONS: Compared to traditional orthodontics with fixed appliances, patients managed with clear aligners after OS (surgery-first approach) had better periodontal health and QoL outcomes.

Cross-sectional evaluation of periodontal inflammation and oral hygiene status between fixed appliances and Invisalign in patients affected by craniofacial anomalies.

OBJECTIVE: The objective of this cross-sectional study was to compare the difference in the oral health status and oral hygiene of orthodontic treatment with aligners (AL) and with fixed appliances (FA) in patients affected by craniofacial anomalies (CFA). MATERIALS AND METHODS: The sample consisted of 100 Caucasian patients affected by various CFA from two different hospitals. Fifty patients treated with AL were matched for sex, age and CFA with a control sample of 50 patients treated with FA. Patients' periodontal conditions were evaluated in both samples. O'Leary Plaque Control Record, bleeding on probing (BOP) and DMT/dmft Index were evaluated in both samples. RESULTS: The FA group presented an O'Leary Plaque Control Record of 60% ± 30, while AL presented an O'Leary Plaque Control Record of 40% ± 29.7 (p-value = 0.02), BOP was 22.1% ± 14 in FA and 12% ± 0.13 in AL (p-value = 0.03). The DMFT/dmft was not statistically different (p-value = 0.13). p-value was set at <0.039. CONCLUSION: The study shows that the sample with FA presented a higher O'Leary Plaque Control Record and BOP compared to the AL sample. AL might, therefore, be an interesting alternative to FA in patients with CFA, who generally have a lower level of oral hygiene.

Risk Factors of Composite Attachment Loss in Orthodontic Patients during Orthodontic Clear Aligner Therapy: A Prospective Study.

BACKGROUND: The composite attachment loss during orthodontic clear aligner therapy is an adverse event that commonly happens in our daily practice. However, there is a lack of related statistical analysis and studies analyzing the related risk factors. Therefore, the aim of this study is to assess the incidence of attachment loss during orthodontic clear aligner therapy and to identify rick factors that may predict such event. MATERIALS AND METHODS: The demographics and clinical variables of 94 patients undergoing clear aligner therapy (27 males and 67 females; average age: 27.60 ± 0.86 years) were recorded. Both patient-related and tooth-related attachment loss was recorded. The chi-squared test and logistic regressive analysis were applied to identify the potential risk factors. SPSS for Mac (version 23.0, IBM, USA) was used for statistical analyses. P < 0.05 was considered statistically significant. RESULTS: Our study suggested that the risk factors for attachment loss include frequent aligner removal (≥ 5 times a day) (losing rate = 60.0%, P = 0.005), aligner wear time less than 18 hours a day (losing rate = 50.8%, P = 0.014), eating without aligners inserted (losing rate = 47.9%, P = 0.034), utilizing aligner tray seaters (losing rate = 48.2%, P = 0.006), and unilateral mastication (losing rate = 52.1%, P = 0.002). The multivariable logistic regression analysis indicates that aligner wear time less than 18 hours a day (P = 0.020, B = 0.925), using aligner tray seaters (P = 0.007, B = 1.168), and unilateral mastication (P = 0.034, B = -0.458) were considered independent factors that can predict the composite attachment loss in orthodontic clear aligner therapy. CONCLUSION: Wearing aligner less than 18 hours a day, using aligner tray seaters, and unilateral mastication may contribute to increased incidence of composite attachment loss during orthodontic clear aligner therapy.

The periodontal status of removable appliances vs fixed appliances: A comparative meta-analysis.

BACKGROUND: Although several researchers have analyzed the dental identity of patients experience with corrective methods using fixed and removable appliances, the consequences stay debatable. This meta-analysis intended to verify whether the periodontal status of removable appliances is similar to that of the conventional fixed appliances. METHODS: Relevant literature was retrieved from the database of Cochrane library, PubMed, EMBASE, and CNKI until December 2019, without time or language restrictions. Comparative clinical studies assessing periodontal conditions between removable appliances and fixed appliances were included for analysis. The data was analyzed using the Stata 12.0 software. RESULTS: A total of 13 articles involving 598 subjects were selected for this meta-analysis. We found that the plaque index (PLI) identity of the removable appliances group was significantly lower compared to the fixed appliances group at 3 months (OR = -0.57, 95% CI: -0.98 to -0.16, P = .006) and 6 months (OR = -1.10, 95% CI: -1.60 to -0.61, P = .000). The gingival index (GI) of the removable appliances group was lower at 6 months (OR = -1.14, 95% CI: -1.95 to -0.34, P = .005), but the difference was not statistically significant at 3 months (OR = -0.20, 95% CI: -0.50 to 0.10, P = .185) when compared with that of the fixed appliances group. The sulcus probing depth (SPD) of the removable appliances group was lower compared to the fixed appliances group at 3 months (OR = -0.26, 95% CI: -0.52 to -0.01, P = .047) and 6 months (OR = -0.42, 95% CI: -0.83 to -0.01, P = .045). The shape of the funnel plot was symmetrical, indicating no obvious publication bias in the Begg test (P = .174); the Egger test also indicated no obvious publication bias (P = .1). CONCLUSION: Our meta-analysis demonstrated that malocclusion patients treated with the removable appliances demonstrated a better periodontal status as compared with those treated with fixed orthodontic appliances. However, the analyses of more numbers of clinical trials are warranted to confirm this conclusion.

Expansion treatment using Invisalign®: Periodontal health status and maxillary buccal bone changes. A clinical and tomographic evaluation.

The aim of this study was to evaluate changes in periodontal status and maxillary buccal bone by considering clinical and tomographic parameters during the first year of orthodontic expansion with Invisalign® aligners. Upper first (1PM) and upper second (2PM) premolars of 19 patients with orthodontic expansion requirement treated with Invisalign® aligners were evaluated. Plaque index (PI), gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL) and cone beam tomographic (CBCT) records were collected at 76 sites before starting treatment (T0) and at 12 months (T1). Bone height was measured from cementoenamel junction (CEJ) to the crest cortical bone (CC). Bone thickness was measured at two levels: 4 mm (CEJ+4) and 6 mm (CEJ+6) apical to the CEJ. A descriptive analysis was made of the variations of bone thickness and height in a series of cases. The average expansion was 1.93 mm for 1PM and 167 mm for 2PM. Arithmetic mean of distance CEJ-CC in 1PM was 3.05 mm at T0, and remained at 3.05 mm at T1. Arithmetic mean of distance CEJ-CC in 2PM was 2.06 mm at T0 and 2.31 at T1. Post-expansion, most of the analyzed sites (86%) exhibited a bone thickness of ≥0.5 mm. The greatest variations between T0 and T1 were observed at the level of 1PM CEJ+ 4 and 2PM CEJ+ 6. The minimal changes in the clinical records (GI, PI, PPD and CAL) between T0 and T1 were compatible with the maintenance of gingivalperiodontal health. Invisalign® for expansion movements did not produce substantial changes in the evaluated periodontal clinical parameters or in the bone measurements. Removable appliances reduce plaque retentive factors and favor adequate oral hygiene.

El objetivo de este estudio fue evaluar los cambios en el estado periodontal y hueso facial maxilar a través de parámetros clínicos y tomográficos durante la expansión ortodóncica con alineadores Invisalign® en el primer año de tratamiento. Se evaluaron los primeros (1PM) y segundos (2PM) premolares superiores pertenecientes a 19 pacientes con requerimiento de expansión ortodóncica tratados con alineadores Invisalign®. Se registraron los índices de placa (IP), índice gingival (IG), profundidad al sondaje (PS) y nivel de inserción (NI) y registros tomográficos de haz cónico (CBCT) en 76 sitios antes de comenzar el tratamiento (T0) y a los 12 meses (T1). Se midió la altura ósea desde el límite amelocementario (LAC) hasta la cortical de la cresta (CC) y el espesor en dos niveles; a 4 mm (LAC+4) y a 6 mm (LAC+6) hacia apical del LAC. Se realizó un análisis descriptivo de las variaciones de la altura y espesor óseo en una serie de casos. La expansión promedio para 1PM fue de 1,93 mm y para 2PM fue de 1,67 mm. La media aritmética de LAC-CC en primeros premolares fue de 3,05 mm en T0 y se mantuvo el valor de 3,05 mm en T1. La media aritmética de LAC-CC en segundos premolares fue de 2,06 mm en T0 y 2,31 en T1. Post expansión, la mayoría de los sitios (86%) analizados exhibieron un espesor óseo ≥0,5 mm. Las mayores variaciones entre T0 y T1 se observaron a nivel de 1PM CEJ+4 y 2PM CEJ+6. Los registros clínicos (PI, GI, PPD y CAL) evidenciaron mínimos cambios entre T0 y T1, compatibles con el mantenimiento de la salud gíngivo-periodontal. El uso de Invisalign ® para movimientos de expansión no produjo cambios sustanciales en los parámetros clínicos periodontales evaluados ni en las mediciones óseas. La aparatología removible reduce los factores retentivos de placa bacteriana y facilita una adecuada higiene oral.

Expansion treatment using Invisalign®: Periodontal health status and maxillary buccal bone changes. A clinical and tomographic evaluation / Tratamiento de expansión con Invisalign®: estado de salud periodontal y cambios óseos maxilares. Evaluación clínica y tomográfica

ABSTRACT The aim of this study was to evaluate changes in periodontal status and maxillary buccal bone by considering clinical and tomographic parameters during the first year of orthodontic expansion with Invisalign® aligners. Upper first (1PM) and upper second (2PM) premolars of 19 patients with orthodontic expansion requirement treated with Invisalign® aligners were evaluated. Plaque index (PI), gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL) and cone beam tomographic (CBCT) records were collected at 76 sites before starting treatment (T0) and at 12 months (T1). Bone height was measured from cementoenamel junction (CEJ) to the crest cortical bone (CC). Bone thickness was measured at two levels: 4 mm (CEJ+4) and 6 mm (CEJ+6) apical to the CEJ. A descriptive analysis was made of the variations of bone thickness and height in a series of cases. The average expansion was 1.93 mm for 1PM and 167 mm for 2PM. Arithmetic mean of distance CEJ-CC in 1PM was 3.05 mm at T0, and remained at 3.05 mm at T1. Arithmetic mean of distance CEJ-CC in 2PM was 2.06 mm at T0 and 2.31 at T1. Post-expansion, most of the analyzed sites (86%) exhibited a bone thickness of ≥0.5 mm. The greatest variations between T0 and T1 were observed at the level of 1PM CEJ+ 4 and 2PM CEJ+ 6. The minimal changes in the clinical records (GI, PI, PPD and CAL) between T0 and T1 were compatible with the maintenance of gingivalperiodontal health. Invisalign® for expansion movements did not produce substantial changes in the evaluated periodontal clinical parameters or in the bone measurements. Removable appliances reduce plaque retentive factors and favor adequate oral hygiene.

RESUMEN El objetivo de este estudio fue evaluar los cambios en el estado periodontal y hueso facial maxilar a través de parámetros clínicos y tomográficos durante la expansión ortodóncica con alineadores Invisalign® en el primer año de tratamiento. Se evaluaron los primeros (1PM) y segundos (2PM) premolares superiores pertenecientes a 19 pacientes con requerimiento de expansión ortodóncica tratados con alineadores Invisalign®. Se registraron los índices de placa (IP), índice gingival (IG), profundidad al sondaje (PS) y nivel de inserción (NI) y registros tomográficos de haz cónico (CBCT) en 76 sitios antes de comenzar el tratamiento (T0) y a los 12 meses (T1). Se midió la altura ósea desde el límite amelocementario (LAC) hasta la cortical de la cresta (CC) y el espesor en dos niveles; a 4 mm (LAC+4) y a 6 mm (LAC+6) hacia apical del LAC. Se realizó un análisis descriptivo de las variaciones de la altura y espesor óseo en una serie de casos. La expansión promedio para 1PM fue de 1,93 mm y para 2PM fue de 1,67 mm. La media aritmética de LAC-CC en primeros premolares fue de 3,05 mm en T0 y se mantuvo el valor de 3,05 mm en T1. La media aritmética de LAC-CC en segundos premolares fue de 2,06 mm en T0 y 2,31 en T1. Post expansión, la mayoría de los sitios (86%) analizados exhibieron un espesor óseo ≥0,5 mm. Las mayores variaciones entre T0 y T1 se observaron a nivel de 1PM CEJ+4 y 2PM CEJ+6. Los registros clínicos (PI, GI, PPD y CAL) evidenciaron mínimos cambios entre T0 y T1, compatibles con el mantenimiento de la salud gíngivo-periodontal. El uso de Invisalign ® para movimientos de expansión no produjo cambios sustanciales en los parámetros clínicos periodontales evaluados ni en las mediciones óseas. La aparatología removible reduce los factores retentivos de placa bacteriana y facilita una adecuada higiene oral.

Salivary concentrations of Streptococcus mutans and Lactobacilli during an orthodontic treatment. An observational study comparing fixed and removable orthodontic appliances.

AIM: This study aimed to investigate salivary concentrations of Streptococcus mutans (S. mutans) and some Lactobacilli, and plaque index (PI) in patients wearing fixed versus removable orthodontic appliances. METHODS: A sample of 90 orthodontic patients (56 males and 34 females) was included in the study: 30 subjects (aged 21.5±1.5 years) were treated with removable clear aligners (CA), while for other 30 cases (aged 23.3±1.6 years) a fixed multibrackets appliance (MB) were utilized, and 30 patients (aged 18.2 ±1.5 years) wearied a removable positioner (RP). Salivary concentrations of S. mutans and Lactobacilli and PI were evaluated prior to start of the orthodontic treatment, after 3 months and 6 months. RESULTS: After 6 months, 40% of MB patients (12 subjects over 30) showed a concentration of S. mutans associated to high risk of developing tooth decay (CFU/ml>105 ), differently from participants wearing removable appliances (odds ratio = 5.05; 95% C.I. = 1.72-14.78; chi-square = 9.64; p = 0.0019). The same trens was observed for the concentration of Lactobacilli (odds ratio = 4.33; 95% C.I. = 1.53-12.3; chi-square = 8.229; p = 0.004). In addition, over the duration of the study, CA patients maintained PI at 0 level, while MB patients experienced a statistically significant increasing trend of PI over time, and their PI became clinically/statistically relevant after 6 months, respect to CA and RP patients. CONCLUSIONS: Comparing all the data, while, after 6 months, only about 10% of CA patients and 13.3% of RP patients achieved a microbial colonization which may lead to high risk of caries development, about 40% of MB patients - and 20% after 3 months - showed a high level of vulnerability to developing caries, which require additional strategies for plaque control and microbial colonization to be employed.

Comparative evaluation of salivary microbial levels and periodontal status of patients wearing fixed and removable orthodontic retainers.

INTRODUCTION: The purpose of this study was to compare and evaluate salivary microbial levels and periodontal status in patients using a fixed lingual retainer, a removable vacuum-formed retainer, or a Hawley retainer after orthodontic treatment with fixed appliances. METHODS: Forty-five patients who finished their orthodontic treatment with fixed appliances and were about to start the retention phase were randomly divided into the following 3 groups of 15 individuals each: the fixed lingual retainer group, the vacuum-formed retainer group, and the Hawley retainer group. Periodontal measurements, such as the plaque index, gingival index, probing depth, and bleeding on probing, were obtained at the following 4 time points: at debonding (T0) and 1 week (T1), 5 weeks (T2), and 13 weeks (T3) after debonding. Saliva samples were collected 3 times in total: at T0, T2, and T3. A quantitative analysis for Streptococcus mutans and Lactobacillus casei was performed with the use of real-time polymerase chain reaction. The Kruskal-Wallis test and 1-way analysis of variance were used for the statistical comparisons of the groups. RESULTS: No statistically significant difference in salivary S mutans and L casei levels was found among the 3 groups (P >0.05). They showed no statistically significant differences in plaque index, gingival index, bleeding on probing, and probing depth values (P >0.05). All periodontal parameters showed statistically significant decreases from T0 to T3 in all 3 groups (P <0.001). The S mutans and L casei levels were decreased significantly from T2 to T3 in the lingual retainer and Hawley retainer groups, whereas they decreased significantly from T0 to T3 in the vacuum-formed retainer group. CONCLUSIONS: Fixed and removable orthodontic retainers do not differ in salivary S mutans and L casei levels and periodontal status. With all retainers, regardless of whether they are fixed or removable, oral hygiene improved after orthodontic treatment with fixed appliances.

Effects of Invisalign® treatment on speech articulation.

OBJECTIVES: To determine the effects of Invisalign® aligners on patients' abilities to articulate consonants. MATERIALS AND METHODS: Thirty patients undergoing active two-arch Invisalign® treatment were examined. Patients were recorded reading the rainbow passage (a passage with every phoneme represented), once with the trays inserted and once with the trays removed. The recordings were analysed by a speech pathologist for misarticulation of consonant phonemes. RESULTS: Misarticulation of consonants was significantly associated with the Invisalign® aligners inserted as based on the McNemar's statistical test (P=0.008). The fricative alveolar consonant /z/ was found to be the most impacted by the trays, followed by the consonant /s/ (P=0.016). The consonant /sh/ was not shown to be affected by the Invisalign® aligners. CONCLUSIONS: Invisalign® aligners do have an impact on the articulation of consonants. Fricative alveolar consonants were the primary phonemes impacted. Due to the fact that the efficacy of Invisalign® treatment is based primarily on compliance and that speech impairment may interfere with compliance, the information presented in this study should be conveyed to the patient before the initiation of Invisalign® treatment.

In vitro cytotoxicity of different thermoplastic materials for clear aligners.

OBJECTIVES: To investigate the in vitro cytotoxicity of different thermoplastic materials for clear aligners on human primary gingival fibroblasts (HGFs). MATERIALS AND METHODS: Four materials for clear aligners were considered in this study: Duran (Scheu-Dental GmbH, Iserlohn, Germany), Biolon (Dreve Dentamid GmbH, Unna, Germany), Zendura (Bay Materials LLC, Fremont, CA, USA), and SmartTrack (Align Technology, San Jose, CA, USA). Three out of four materials (Duran, Biolon, Zendura) were assessed as thermoformed and nonthermoformed, whereas the SmartTrack was assessed only as thermoformed. The samples were placed at 37°C in airtight test tubes containing Dulbecco's Modified Eagle's Medium (DMEM; 0.1 mg/mL) for 14 days. The cell viability of HGFs cultured with this medium was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Data were analyzed by means of one-way and two-way analysis of variance and post hoc tests (α = 0.05). RESULTS: Each material exhibited a slight cytotoxic effect after 14 days. The highest cytotoxicity level on HGFs was achieved by Biolon (64.6% ± 3.3 of cell viability), followed by Zendura (74.4% ± 2.3 of cell viability), SmartTrack (78.8% ± 6.3 of cell viability), and finally Duran (84.6% ± 4 of cell viability), which was the least cytotoxic. In the comparison between nonthermoformed and thermoformed materials for Duran, Biolon, and Zendura, the thermoformed materials showed the highest level of cytotoxicity (P < .001). CONCLUSIONS: Under the experimental conditions of this study, all the materials for clear aligners presented a slight cytotoxicity. Biolon was the most cytotoxic and the thermoforming process increased the cytotoxicity of the materials.

Use of bibloc and monobloc oral appliances in obstructive sleep apnoea: a multicentre, randomized, blinded, parallel-group equivalence trial.

Background: The clinical benefit of bibloc over monobloc appliances in treating obstructive sleep apnoea (OSA) has not been evaluated in randomized trials. We hypothesized that the two types of appliances are equally effective in treating OSA. Objective: To compare the efficacy of monobloc versus bibloc appliances in a short-term perspective. Patients and methods: In this multicentre, randomized, blinded, controlled, parallel-group equivalence trial, patients with OSA were randomly assigned to use either a bibloc or a monobloc appliance. One-night respiratory polygraphy without respiratory support was performed at baseline, and participants were re-examined with the appliance in place at short-term follow-up. The primary outcome was the change in the apnoea-hypopnea index (AHI). An independent person prepared a randomization list and sealed envelopes. Evaluating dentist and the biomedical analysts who evaluated the polygraphy were blinded to the choice of therapy. Results: Of 302 patients, 146 were randomly assigned to use the bibloc and 156 the monobloc device; 123 and 139 patients, respectively, were analysed as per protocol. The mean changes in AHI were -13.8 (95% confidence interval -16.1 to -11.5) in the bibloc group and -12.5 (-14.8 to -10.3) in the monobloc group. The difference of -1.3 (-4.5 to 1.9) was significant within the equivalence interval (P = 0.011; the greater of the two P values) and was confirmed by the intention-to-treat analysis (P = 0.001). The adverse events were of mild character and were experienced by similar percentages of patients in both groups (39 and 40 per cent for the bibloc and monobloc group, respectively). Limitations: The study shows short-term results with a median time from commencing treatment to the evaluation visit of 56 days and long-term data on efficacy and harm are needed to be fully conclusive. Conclusion: In a short-term perspective, both appliances were equivalent in terms of their positive effects for treating OSA and caused adverse events of similar magnitude. Trial registration: Registered with ClinicalTrials.gov (#NCT02148510).

In Vitro Assessment of Cytotoxicity and Estrogenicity of Vivera® Retainers.

AIM: To investigate the cytotoxicity and estrogenicity of Vivera® retainers by assessing their biological behavioral effects as-received from the manufacturer and after retrieved from patients. MATERIALS AND METHODS: In this, in vitro investigation six sets (maxillary and mandibular) of Vivera® retainers, three as received and three retrieved after four weeks of use by patients of an orthodontic postgraduate clinic, were immersed in the normal saline solution for 14 days following different modes of sterilization. The estrogenicity assays involved two cell lines, namely the estrogen-sensitive MCF-7 and the estrogen-insensitive MDA-MB-231. Following a 6 day incubation with the solutions to be tested, at concentrations varying from 5% to 20% v/v in medium supplemented with 2% fetal calf serum devoid of endogenous estrogens, estrogenicity was assessed by cell counting; p-Estradiol was used as positive control. The statistical analysis of data was performed with two-way analysis of variance (ANOVA) with appliance and concentration as predictors. Differences were further investigated with the Tukey multiple comparison tests at the 0.05 level of significance. RESULTS: No significant MCF-7 proliferation was induced by the three samples compared either to the eluents from as-received retainers or to the negative control. As expected, p-estradiol induced a potent stimulation of MCF-7 cell proliferation, while no effect was observed on MDA-MB-231 cells. CONCLUSION: Under the conditions of this experiment eluents of as-received and retrieved Vivera® retainers did not seem to exhibit xenoestrogenic activity. CLINICAL SIGNIFICANCE: Vivera® retainers can be used as part-time removable oral appliances following the manufacturer's instructions.

Salivary levels of cariogenic bacterial species during orthodontic treatment with thermoplastic aligners or fixed appliances: a prospective cohort study.

BACKGROUND: Fixed orthodontic appliances might be associated with intraoral adverse effects on enamel, due to plaque accumulation and their colonization by oral microbes. At the same time, the demand for esthetic alternatives to orthodontic treatment, like thermoplastic aligners, is growing. However, thermoplastic aligners may behave differently intraorally than fixed appliances in terms of bacterial colonization and biofilm formation. Therefore, the aim of this prospective cohort study was to assess the salivary prevalence of the cariogenic bacteria Streptococcus mutans, Lactobacillus acidophilus, and Streptococcus sanguinis among adolescents treated orthodontically with thermoplastic aligners or fixed appliances. METHODS: Thirty adolescent patients (17 girls/13 boys; mean age 13.8 years old) were assigned to treatment with either (i) self-ligating fixed appliances with nickel-titanium archwires or (ii) aligners constructed from clear transparent polyethylenterephthalat-glycol copolyester (PET-G) thermoplastic sheets. Whole stimulated saliva was collected from each patient at three time points: at baseline (before bonding and initiation of orthodontic therapy or before insertion of the thermoplastic aligners), after 2 weeks, and after 1 month. A simplified plaque index, a simplified gingival index, and the decayed, missing, and filled teeth (DMFT) index were assessed from the clinical examination of the patients. Microbiological analysis of salivary bacteria was performed by quantitative polymerase chain reaction, followed by descriptive and inferential statistics at the 5% level. RESULTS: Although patients treated with aligners had significantly lower plaque and gingivitis scores throughout treatment compared to patients treated with fixed appliances, no significant difference could be found between the S. mutans counts of the two groups at any time through treatment (P > 0.05). On the other hand, patients treated with aligners had significantly lower salivary S. sanguinis counts at all time points than patients treated with fixed appliances (P < 0.05). Finally, almost no L. acidophilus were identified in the collected saliva samples in either of the treated samples. CONCLUSIONS: Within the limitations of this study, there were no differences in the salivary counts of S. mutans or L. acidophilus among adolescent patients treated for 1 month with thermoplastic aligners or self-ligating appliances. On the other hand, patients treated with aligners had lower salivary levels of S. sanguinis compared to those treated with self-ligating appliances.

Risk factors for the efficacy of oral appliance for treating obstructive sleep apnea: A preliminary study.

OBJECTIVE: To identify potential risk factors of response to oral appliance in patients with obstructive sleep apnea (OSA). METHODS: Fifteen OSA patients were enrolled. Clinical characteristics, cephalometric measurements, and the results of home sleep testing were retrospectively obtained at baseline, and a sleep test was done again at the end of treatment. RESULTS: Twelve subjects were responders and three were non-responders. The diastolic blood pressure, minimum pulse rate, SNA (Angle between sella-nasion and nasion-A point), ANB (Anteroposterior maxilla/mandible discrepancy), and facial convexity of non-responders was higher than those of responders. Unlike AHI, non-responders showed a lower lowest oxygen saturation (%) than responders. DISCUSSION: Elevated diastolic pressure and minimal pulse rate, higher skeletal convexity and lowered lowest oxygen saturation might be risk factors to oral appliance efficacy in the OSA patients. More research in a large sample is needed to verify the results of the current study.

Association of Orthodontic Clear Aligners with Root Resorption Using Three-dimension Measurements: A Systematic Review.

AIM: This paper aims to assess the evidence in the literature reporting orthodontically induced inflammatory root resorption (OIIRR) in treatment with orthodontic clear aligners using 3D measurements. MATERIALS AND METHODS: Following preferred reporting Items for systematic reviews (PRISMA) statement, eight electronic databases were searched for relevant published and unpublished records. Data collected according to restricted inclusion and exclusion criteria. RESULTS: A total of 236 articles were identified as relevant to our topic. Duplicates were excluded resulting in 226 papers, out of which 31 papers were relevant after screening titles and abstracts. Only 2 high-level evidence papers out of the 31 met the inclusion criteria for the qualitative synthesis. CONCLUSION: Based on the available studies with high level of evidence in the literature, we conclude that orthodontic clear aligners are non-inferior to light-force fixed orthodontic appliances, and superior to heavy-force fixed orthodontic appliances in terms of the risk for developing apical root resorption. CLINICAL SIGNIFICANCE: Orthodontists can be more assured about the low-risk of OIIRR associated with clear aligners compared to other orthodontic treatment modalities, and it remains up to the practitioner's assessment to select the appropriate treatment on a case by case basis.

Adverse clinical events reported during Invisalign treatment: Analysis of the MAUDE database.

INTRODUCTION: The objectives of this study were to examine adverse clinical events after the use of the Invisalign system and to provide an overview of the actions taken by the manufacturer to address these events. METHODS: A retrospective analysis of the Manufacturer and User Facility Device Experience database of the United States Food and Drug Administration was used. All medical device reports reported to the United States Food and Drug Administration pertaining to products of Align Technology from November 1, 2006, to November 30, 2016, were analyzed. Qualitative content analysis was conducted of event descriptions and manufacturer narrative reports. RESULTS: A total of 173 medical device reports were reported in the Manufacturer and User Facility Device Experience database: 169 (97.7%) were designated as adverse event reports, and 45 (26%) were deemed by the treating doctor to be serious or life threatening. The most medical device reports that reported a serious or life-threatening event were in 2014 (50%). The most frequently reported adverse event was difficulty breathing (56 events) followed by sore throat (35 events), swollen throat (34 events), swollen tongue (31 events), hives and itchiness (31 events), anaphylaxis (30 events), swollen lips (27 events), and feeling of throat closing/tight airway/airway obstruction/laryngospasm (24 events). CONCLUSIONS: Serious or life-threatening events could be associated with use of Invisalign systems. Health care providers should be aware of these events and know how to handle them if they arise in their practices.