Recording the maxillomandibular relationship with the Aqualizer system prior to occlusal splint therapy for treating temporomandibular disorders: a randomized controlled trial

Temporomandibular disorders (TMD) present a public health issue and are one of the most common musculoskeletal conditions causing chronic pain. This study compares the outcomes of occlusal splint therapy in patients with TMD following two different maxillomandibular relationship (MMR) registration techniques. 40 TMD patients were randomly allocated to MMR registration with the Aqualizer system (AQU) or with chin point guidance (CPG) prior to fabricating occlusal splints. TMD symptoms, subjective pain intensity, and quality of life (QoL) were recorded at baseline and after 3 and 6 months. The treatment led to an overall reduction of TMD symptoms in both groups (Conover test, p < 0.00001). TMJ sounds, TMJ pain with palpation and muscle pain with palpation subsided regardless of the type of MMR registration method used (Cohen's d > 0.8). AQU-based occlusal splints led to a better improvement of TMJ pain with maximum opening compared to CPG-based occlusal splints (Cohen's d = 0.9; CPG d = 0.13). In both groups, occlusal splint treatment had little to no effect on correcting lateral mandible deviation or improving restricted jaw opening. After 6 months occlusal splints in both groups had a large effect on improving subjective pain intensity (Cohen's d > 0.8), however, patients reported a higher QoL in the AQU group compared to the CPG group (Mann-Whitney-U-test, p < 0.05). The results of this study support the premise that occlusal splints are effective in relieving pain-related TMD symptoms. The Aqualizer can be considered for determining MMR in cases, where guided registration techniques are not possible.Trial registration: DRKS00031998.

The prevalence of treatment-emergent central sleep apnea with mandibular advancement device therapy

STUDY OBJECTIVES

Treatment-emergent central sleep apnea (TECSA) describes the appearance or persistence of central sleep apnea while undergoing treatment for obstructive sleep apnea. TECSA is well studied in continuous positive airway pressure therapy with an estimated prevalence of 8%. Based on a few case reports, mandibular advancement devices (MAD) may also provoke TECSA. This study aims to gain insight into the prevalence of TECSA with MAD therapy.

METHODS

This retrospective study includes a total of 129 patients with moderate to severe obstructive sleep apnea who were treated with a custom-made titratable MAD. Baseline and follow-up sleep studies were compared to identify patients with TECSA. Since different diagnostic criteria to define TECSA are used in literature, prevalence was calculated according to three definitions (TECSA-1, -2, and -3). Demographics, MAD treatment variables, and findings of the diagnostic polysomnography were compared between TECSA and non-TECSA patients to identify possible predictors.

RESULTS

Depending on the definition used, TECSA was found in 3.1%-7.8% of patients undergoing MAD therapy. TECSA patients had a higher apnea index (9.2 vs 2.0 events/h, P = .042), central apnea-hypopnea index (4.1 vs 0.2 events/h, P = .045) and oxygen desaturation index (23.9 vs 16.3 events/h, P = .018) at baseline compared to non-TECSA patients. No differences were found in demographics and treatment variables.

CONCLUSIONS

These findings demonstrate that TECSA also occurs in patients starting MAD treatment. Patients with TECSA had a higher apnea index, central apnea-hypopnea index, and oxygen desaturation index at baseline compared to non-TECSA patients.

CITATION

Hellemans S, Van de Perck E, Braem MJ, Verbraecken J, Dieltjens M, Vanderveken OM. The prevalence of treatment-emergent central sleep apnea with mandibular advancement device therapy. J Clin Sleep Med. 2023;19(12):2035-2041.

Factors associated with treatment adherence to mandibular advancement devices: a scoping review

PURPOSE

Obstructive sleep apnea (OSA) is frequently treated with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs). For various reasons, both treatment options are often affected by low adherence. While factors associated with low CPAP adherence are described in the literature extensively, less is known about adherence to MAD therapy. This scoping review aimed to synthesize the body of literature on the factors associated with adherence to MAD treatment.

METHODS

A systematic literature search was conducted using bibliographic databases PubMed, Embase.com , Web of Science, and the Cochrane Library (Wiley) to identify relevant studies that described factors associated with adherence to MAD in the treatment of OSA or snoring combined with OSA in adults.

RESULTS

The literature search yielded a total of 694 references. Forty studies were found eligible for inclusion. The literature showed that factors with a possible negative influence on the adherence to MAD treatment are personality aspects; failing effectiveness of MAD; side effects during MAD therapy; using a thermoplastic MAD; dental treatments during MAD therapy; and a poor first experience with the MAD with inadequate guidance by professionals. Factors that may have a positive effect on MAD adherence include effectiveness of therapy, custom-made MAD, good communication skills of the practitioner, early recognition of side effects, stepwise titration of the MAD, and positive first experience with MAD.

CONCLUSIONS

The knowledge of factors associated with MAD adherence can be used to provide further insight into individual adherence to OSA treatments.

Occurrence of Temporomandibular Disorders among patients undergoing treatment for Obstructive Sleep Apnoea Syndrome (OSAS) using Mandibular Advancement Device (MAD): A Systematic Review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions

BACKGROUND

Patients undergoing mandibular advancement device (MAD) therapy for obstructive sleep apnea (OSA) may experience changes in jaw position and altered occlusion. This could potentially contribute to the development or exacerbation of TMD symptoms. The literature on the long-term impact of MAD treated for OSA on TMD is scarce. Hence, this review was undertaken to ascertain the occurrence of TMD in MAD users.

METHODS

A comprehensive search protocol was implemented across several online databases using MeSH keywords and Boolean operators. A standardised data extraction form was developed specifically for this review. Two reviewers independently extracted the data. RoB-2 was used to evaluate the methodological quality of the included studies.

RESULTS

A total of 13 clinical studies were selected for this review. Some studies reported a significant reduction in the severity and frequency of TMD symptoms following MAD treatment. However, other studies did not observe significant changes in TMD symptoms or TMJ-related parameters from baseline to follow-up intervals. Temporary increases in TMJ-related pain or symptoms at the beginning of the follow-up period, which later subsided, were reported in some studies. Overall, MAD was not discontinued in any OSA patient due to TMDs.

CONCLUSION

The findings reveal that different outcomes associated with TMD are affected differently by MAD treatment for OSAS. According to a few studies, MAD therapy significantly reduced the severity and frequency of TMD symptoms. Other research, however, found no appreciable modifications in TMD symptoms or TMJ-related indicators. Although the overall results point to no significant effect of MAD treatment on TMD symptoms, the disparity in results between studies highlights the need for additional studies using standardised approaches.

Mechanical and chemical characterization of contemporary occlusal splint materials fabricated with different methods: a systematic review

OBJECTIVE

To systematically review studies on various occlusal splint materials and describe their mechanical and chemical properties.

METHODS

MEDLINE (PubMed), Scopus, and Web of Science searches were conducted for in vitro studies focusing on occlusal splint materials. Two reviewers performed an assessment of the identified studies and data abstraction independently, and this was complimented by an additional hand search. The articles were limited to those in the English language that were published between January 1st, 2012, and December 1st, 2022.

RESULTS

The initial search yielded 405 search results of which 274 were selected for full-text review following abstract evaluation. 250 articles that did not meet the inclusion criteria were excluded, and the remaining 25 articles (with 1 article identified from the reference lists of included articles) providing mechanical and chemical values were used in this review. Poly methyl methacrylate (PMMA) -based occlusal splint materials showed the highest values in terms of hardness, wear resistance, flexural strength, flexural modulus, e-modulus, and fracture toughness. The material group with the highest water sorption and water solubility was 3D printed (PR) splint materials. In addition, the lowest degree of double bond conversion was also observed in this group of materials.

CONCLUSIONS

The outcome of this review suggests that mechanically and chemically acceptable properties can be attained with PMMA-based occlusal splint materials using both conventional and digital production methods. PR splint materials should not be considered as the primary choice for long-term treatments due to their low mechanical and chemical properties.

CLINICAL RELEVANCE

This review provides clinical recommendations for selecting the appropriate material and fabrication method for occlusal splints while taking the patients' needs and the materials´ mechanical and chemical properties into account.

CAD-CAM and analog occlusal splints comparison based on the amount of occlusal adjustments. 3D analysis of the volumetric changes: A pilot study

OBJECTIVE

To evaluate the volumetric changes on occlusal surface of computer-aided design and computer-aided manufacturing (CAD-CAM) occlusal devices fabricated following a fully digital workflow after occlusal adjustment, compared to those fabricated with an analog workflow.

MATERIALS AND METHODS

Eight participants were included in this clinical pilot study, receiving two different occlusal devices fabricated with two different workflows, fully analog and fully digital. Every occlusal device was scanned before and after the occlusal adjustments to compare the volumetric changes using a reverse engineering software program. Moreover, three independent evaluators assessed a semi-quantitative and qualitative comparison using visual analog scale and dichotomous evaluation. The Shapiro-Wilk test was performed to validate normal distribution assumption, and a dependent t-Student test for paired variables was used to determine statistically significant differences (p-value < 0.05).

RESULTS

The root mean square value was extracted from the 3-Dimensional (3D) analysis of the occlusal devices. The average values of the root mean square were higher for the analogic technique (0.23 ± 0.10 mm) than the digital technique (0.14 ± 0.07 mm) but the differences were not statistically significant (paired t-Student test; p = 0.106) between the two fabrication techniques. The semiquantitative visual analog scale values between the impression for the digital (5.08 ± 2.4 cm) and analog (3.80 ± 3.3 cm) technique were significant (p < 0.001), and statistically significant differences values were assessed for evaluator 3 compared to the other evaluators (p < 0.05). However, the three evaluators agreed on the qualitative dichotomous evaluation in 62% of the cases, and at least two evaluators agreed in 100% of the evaluations.

CONCLUSIONS

Occlusal devices fabricated following a fully digital workflow resulted in fewer occlusal adjustments, as they could be a valid alternative to those fabricated following an analog workflow.

CLINICAL SIGNIFICANCE

Fabricated occlusal devices following a fully digital workflow could have some advantages over analog workflow such reduce occlusal adjustments at delivery appointment, which can result in reduced chair time and therefore increased comfort for the patient and clinician.

Effects of CPAP and Mandibular Advancement Devices on depressive symptoms in patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials

PURPOSE

Studies show that patients with obstructive sleep apnea (OSA) are more likely than the general population to have psychological disorders such as depression. However, it is less clear how OSA treatment affects this association. This meta-analysis aimed to assess whether or not continuous positive airway pressure (CPAP) and mandibular advancement devices (MADs) reduce depression symptoms in patients with OSA.

METHODS

We searched Pubmed, Embase, Web of Science, and Cochrane Library from creating the databases until November 2022. Our analysis included RCTs that examined CPAP and MAD treatment effectiveness for depression in patients with OSA.

RESULTS

We identified 17 CPAP studies comprising 1,931 patients for inclusion in the meta-analysis. The results of the meta-analysis using a fixed effects model found that CPAP improved depressed mood in patients with OSA relative to controls (SMD = 0.27;95% CI:0.18,0.36), with small heterogeneity among trials (I2 = 8.1% < 50%, P = 0.359). We performed subgroup analyses on three factors: the length of trial follow-up, patient adherence data, and depression assessment scales. The meta-analysis also identified six MAD studies involving 315 patients. According to this analysis, there was no heterogeneity between studies (I2 = 0%, P = 0.748). MADs did not significantly improve depression symptoms compared to controls, indicating a combined effect of SMD = 0.07 (95% CI: - 0.15,0.29), P > 0.05.

CONCLUSION

The present findings confirm that CPAP may improve depressive symptoms in patients with OSA. However, the review results suggest that MADs have no significant effect on depressive symptoms in patients with OSA, a finding that is different from the results of previous meta-analyses.

Long-term efficacy of mandibular advancement devices in the treatment of adult obstructive sleep apnea: A systematic review and meta-analysis

This study aims to review the long-term subjective and objective efficacy of mandibular advancement devices (MAD) in the treatment of adult obstructive sleep apnea (OSA). Electronic databases such as PubMed, Embase, and Cochrane Library were searched. Randomized controlled trials (RCTs) and non-randomized self-controlled trials with a treatment duration of at least 1 year with MAD were included. The quality assessment and data extraction of the included studies were conducted in the meta-analysis. A total of 22 studies were included in this study, of which 20 (546 patients) were included in the meta-analysis. All the studies had some shortcomings, such as small sample sizes, unbalanced sex, and high dropout rates. The results suggested that long-term treatment of MAD can significantly reduce the Epworth sleepiness scale (ESS) by -3.99 (95%CI -5.93 to -2.04, p<0.0001, I2 = 84%), and the apnea-hypopnea index (AHI) -16.77 (95%CI -20.80 to -12.74) events/h (p<0.00001, I2 = 97%). The efficacy remained statistically different in the severity (AHI<30 or >30 events/h) and treatment duration (duration <5y or >5y) subgroups. Long-term use of MAD could also significantly decrease blood pressure and improve the score of functional outcomes of sleep questionnaire (FOSQ). Moderate evidence suggested that the subjective and objective effect of MAD on adult OSA has long-term stability. Limited evidence suggests long-term use of MAD might improve comorbidities and healthcare. In clinical practice, regular follow-up is recommended.

Temporomandibular disorders and the use of traditional and laser acupuncture: a systematic review

OBJECTIVE

To evaluate current studies to establish and compare the efficacy of traditional and laser acupuncture in reducing the signs and symptoms of temporomandibular disorders (TMD).

METHODS

PubMed, Cochrane, Scopus, and Web of Science databases were searched. Clinical, controlled, and randomized trials written in English and having used traditional or laser acupuncture as therapy for TMD and RDC/TMD or DC/TMD as a diagnostic criterion for TMD were included.

RESULTS

Six studies that evaluated the intensity of pain and the level of mouth opening of the patients submitted to acupuncture were selected, and all showed improvement. However, similar results were also observed in the groups treated with occlusal splint and placebo acupuncture. Only one study evaluated laser acupuncture and showed a higher proportion of patients with remission of symptoms in the experimental group.

CONCLUSION

The traditional acupuncture seems to relieve the signs and symptoms of TMD, as well as laser acupuncture when associated with occlusal splint. However, more rigorous and high-quality clinical trials are needed.

Evaluation of enamel wear by 3 occlusal splint materials: An in vitro study

STATEMENT OF PROBLEM

Occlusal devices used to manage bruxism have been commonly fabricated from polymethyl methacrylate with the powder-liquid technique. More recently, Vertex ThermoSens (VTS) and the biocompatible high-performance polymer (BioHPP), an optimized material having polyetheretherketone (PEEK) as its basis, have been used, but little is known about the wear of these materials on human enamel.

PURPOSE

The purpose of this in vitro study was to assess via a mastication simulation test how 3 occlusal device materials affected the wear and roughness of enamel antagonists.

MATERIAL AND METHODS

A noncontact 3D optical profilometer was used to measure the enamel surface roughness (Ra) against 3 occlusal device materials: vertex regular, VTS, and PEEK high-performance polymer (BioHPP). A dual-axis mastication simulator was used to perform a 2-body wear test on specimens from each group. The test consisted of 10 000 cycles with a 70-N force and 5 to 55 °C thermocycling. Following simulated mastication, the weight of each specimen and the Ra change were compared with the Kolmogorov-Smirnov test, paired specimens t test, Wilcoxon signed-rank test, and 1-way analysis of variance (α=.05).

RESULTS

The polyamide group caused the lowest amount of enamel wear (P<.05), while the heat-polymerized acrylic resin group induced the largest amount of enamel wear (P<.05). For polyamide and PEEK, the change in enamel surface roughness exhibited a smooth texture, whereas it found a rougher surface for the heat-polymerized acrylic resin.

CONCLUSIONS

According to this study, surface roughness and wear on human enamel were not correlated. PEEK is a promising material for the fabrication of occlusal devices.

A clinical trial: Aqualizer ™ therapy and its effects on myopathies or temporomandibular dysfunctions. Part II: Subjective parameters

OBJECTIVE

Temporomandibular dysfunction (TMD) reduces patients' quality of life (QoL). The aim was to assess the effects of initial Aqualizer™ therapy.

METHODS

Group 1 (initial Aqualizer™ therapy) before definitive splint therapy or Group 2 (no initial therapy). Patients with arthrosis, partial/total prosthesis, or were undergoing splint therapy were excluded. Subjective parameters were evaluated: duration and intensity of pain, influence on wellbeing, changes in the head/neck area, handling and improvement of the Aqualizer™, improvement in QoL. The statistical significance level was 5% (p < 0.05).

RESULTS

In 53 patients (Group 1 n = 25; Group 2 n = 28), the improvement in patients' well-being and intensity of pain in both groups was significant (p < 0.001). An improvement in QoL was found in 84% of patients in Group 1 and 75% in Group 2.

CONCLUSION

Initial Aqualizer™ therapy can decrease the intensity of pain and increase patients'.

Sports performance adaptations through occlusal splint: Case reports of triathlon athletes

OBJECTIVE

Occlusal disturbances affect human posture and sports performance. This study aimed to monitor biomechanical adaptations to personalized occlusal splints.

METHODS

Splints were customized based on stabilometry, thermography, sEMG, and kinesiography, and administered to three triathlon athletes. They were evaluated during a 4-month period, using isokinetic indexes, running kinematics and anaerobic outputs.

RESULTS

Individuality emerged as a key factor driving type, quantity, quality, and time trajectories of adaptations. The use of instrumental and clinical tests allowed the detection of static balance and biting function improvements, but not necessarily parallel to sports performance improvements.

CONCLUSION

The authors argue that strength and kinematic imbalances are joint and task-specific and support the use of multi-stage monitoring of the biomechanical effect of mouthpieces. Kinematics of cycling and running may be widely assessed with ecological and inexpensive methods. Strength imbalances need to be continuously monitored due to the high informative value to injury prevention.

Comparison accuracy of digital and analog method using milled occlusal splints

OBJECTIVE

This clinical trial aims to compare the accuracy of interocclusal registration in centric relation taken with polyvinyl siloxane and intraoral scanner (IOS) with the fabrication of occlusal devices.

METHODS

Thirty-one participants were included in the trial registered at ClinicalTrials.gov (NCT05317182) receiving two different occlusal devices from two different workflows. One workflow was performed using polyvinyl siloxane impression material and the other with IOS. Every splint was scanned before and after the occlusal adjustments to compare the volumetric changes using the Root Mean Square deviation (RMS). Furthermore, three evaluators assessed the 3D comparison using color maps in a Visual Analog Scale (VAS).

RESULTS

The average values of RMS were higher for the analog approach (0.01 ± 0.067) than the digital approach (0.065 ± 0.035). However, the differences were not statistically significant (p < 0.063) between the two impression techniques. For the semiquantitative analysis performed by blinded evaluators, differences in VAS values between the impression for the digital (2.08 ± 2.4) and analog (3.80 ± 3.3) technique were statistically significant. The three evaluators agreed in more than 90% of the qualitative dichotomous evaluation.

CONCLUSION

Digital impressions did not show inferior accuracy compared to conventional impressions when assessed using quantitative measurements.

CLINICAL SIGNIFICANCE

This clinical trial provided evidence on registering interocclusal relationship at increased vertical dimension with fully digital workflow for complete arch prosthesis.

Effect of build orientation on the trueness of occlusal splints fabricated by three-dimensional printing

PURPOSE

Scientific evidence pertaining to the evaluation of trueness of occlusal splints fabricated using different three-dimensional (3D) printers and build orientations compared to subtractive technologies is lacking.

METHODS

Overall, one hundred and ten occlusal splints were manufactured using two different 3D printers and a dental mill. Five groups of ten were fabricated using the 3D printers at different build orientations (0, 30, 45, 60, and 90 degrees). In addition, a comparison group of ten occlusal splints was subtractively manufactured using a five-axis dental mill. All occlusal splints were scanned and exported as a standard tessellation language file. Analysis was conducted with metrology software with root mean square estimate average positive deviation and average negative deviation used as the measured outcome.

RESULTS

The 0 degree printing orientation was the most accurate for printer one with the root mean square value of 0.05 ± 0.01 mm, and 60 degree printing orientation was most accurate for printer two with the RMS value of 0.11 ± 0.01 mm. Subtractively manufactured occlusal splint had significantly higher trueness with the lowest RMS value of 0.03 ± 0.05 mm.

CONCLUSION

Build orientations influence the trueness of additively manufactured occlusal splints while occlusal splints produced by subtractive manufacturing were statistically significantly more accurate.

Evaluation of mandibular advancement device placement based on levels of TNF-alpha in participants with obstructive sleep apnea: A clinical study

STATEMENT OF PROBLEM

Objective assessments of the effect of mandibular advancement device on patients with obstructive sleep apnea are lacking.

PURPOSE

The purpose of this clinical study was to compare levels of serum tumor necrosis factor alpha (TNF-alpha), Epworth Sleepiness Scale score, and Berlin Questionnaire score in patients with mild to moderate obstructive sleep apnea before and after treatment with a mandibular advancement device.

MATERIAL AND METHODS

Twenty participants diagnosed with mild to moderate obstructive sleep apnea based on polysomnography testing were enrolled. A custom nonadjustable mandibular advancement device with 70% mandibular protrusion was provided for each participant for management of the obstructive sleep apnea. Evaluation of TNF-alpha levels was performed before treatment (baseline) and 3 and 6 months after starting mandibular advancement device therapy by using a Human TNF-alpha enzyme-linked immunoassay (ELISA) sandwich kit. The Epworth Sleepiness Scale and Berlin Questionnaire were also filled out by the participants at the same time intervals (α=.05).

RESULTS

A statistically significant decline in the levels of TNF-alpha was observed at 3 and 6 months compared with baseline (P<.001). The Epworth Sleepiness Scale scores showed a statistically significant reduction at 3 and 6 months compared with baseline (P<.001). The risk of obstructive sleep apnea assessed by using the Berlin Questionnaire was found to be significantly reduced at 6 months compared with baseline (P=.001).

CONCLUSIONS

Patients with mild to moderate obstructive sleep apnea showed reduced levels of TNF-alpha and Epworth Sleepiness Scale and Berlin Questionnaire scores when treated with a mandibular advancement device.

Mandibular advancement devices used with morning occlusal guides for treating obstructive sleep apnea-changed incisor inclination and its associated factors

PURPOSE

Mandibular advancement devices (MADs) effectively treat patients with obstructive sleep apnea (OSA). Although the use of morning occlusal guides (MOGs) along with MADs is recommended to prevent dental side effects, there is no evidence to support this. The aim of this study was to evaluate the change in incisor inclination in patients with OSA treated with MADs and MOGs, and to identify its predictive factors.

METHODS

Patients with OSA who received MAD and MOG therapy and had a reduction in their apnea-hypopnea index greater than 50% were analyzed. Cephalometric measurements were performed at baseline and at a 1-year follow-up or longer to assess the dentoskeletal side effects of MAD/MOG treatment. Multivariable linear regression analysis was used to assess the association between the change in incisor inclination and the independent variables that may cause the observed side effects.

RESULTS

Among 23 patients enrolled in the study, there was significant upper incisor retroclination (U1-SN: 2.83° ± 2.68°, U1-PP: 2.86° ± 2.46°; P < 0.05) and significant lower incisor proclination (L1-SN: 3.04° ± 3.29°, L1-MP: 1.74° ± 3.13°; P < 0.05). However, no significant skeletal changes were observed. Multivariable linear regression revealed that advancement ≥ 95% of the patients' maximal mandibular protrusion was associated with greater upper incisor retroclination. Increased treatment duration was also associated with increased upper incisor retroclination. No \measured variables were associated with the change in lower incisor inclination.

CONCLUSIONS

Dental side effects occurred in patients who used MADs with MOGs. The amount of mandibular protrusion by MADs and treatment duration were predictive factors associated with upper incisor retroclination.

The effects of manufacturing technologies on the surface accuracy of CAD-CAM occlusal splints

PURPOSE

To investigate the effects of the manufacturing technologies on the surface (cameo and intaglio) accuracy (trueness and precision) of computer-aided design and computer-aided manufacturing (CAD-CAM) occlusal splints.

MATERIALS AND METHODS

The digital design of the master occlusal splint was designed in a CAD software program. Six groups (n = 10) were tested in this study, including Group 1 - Milling (Wax), Group 2 - Heat-polymerizing, Group 3 - Milling (M series), Group 4 - Milling (DWX-51/52D), Group 5 - 3D-printing (Cares P30), and Group 6 - 3D-printing (M2). The study samples were placed in a scanning jig fabricated from putty silicone and Type III dental stone. The study samples were then scanned with a laboratory scanner at the intaglio and cameo surfaces, and the scanned files were exported in standard tessellation language (STL) file format. The master occlusal splint STL file, was used as a reference to compare with all scanned samples at the intaglio and cameo surfaces in a surface matching software program. Root mean square (RMS, measured in mm, absolute value) values were calculated by the software for accuracy comparisons. Group means were used as the representation of trueness, and the standard deviation for each group was calculated as a measure of precision. Color maps were recorded to visualize the areas of deviation between study samples and the master occlusal splint file. The data were normalized and transformed to rank scores, and one-way ANOVA was used to test for the differences between the groups. Pairwise comparisons were made between different groups. Fishers least square differences were used to account for the family-wise error rate. A 5% significance level was used for all the tests.

RESULTS

The null hypotheses were rejected. The manufacturing technologies significantly affected the trueness of occlusal splints at both intaglio and cameo surfaces (p < 0.001). At the cameo surfaces, Group 1 - Milling (Wax) (0.03 ± 0.02 mm), Group 3 - Milling (M series) (0.04 ± 0.01 mm), and Group 4 - Milling (DWX-51/52D) (0.04 ± 0.01 mm) had the smallest mean RMS values and highest trueness. Group 3 had the smallest standard deviation and highest precision among all groups (p < 0.001, except p = 0.005 when compared with Group 2). Group 5 had the largest standard deviation and lowest precision among all groups (p < 0.001). At the intaglio surfaces, Group 1 - Milling (Wax) (0.06 ± 0.01 mm) had the smallest RMS values and highest trueness among all groups (p < 0.001), and Group 2 - Heat-polymerizing (0.20 ± 0.03 mm) and Group 5 - 3D-printing (Cares P30) (0.15 ± 0.05 mm) had significantly larger mean RMS and standard deviation values than all other groups (p < 0.001), with lowest trueness and precision. In the color maps, Group 2 - Heat-polymerizing and Group 5 - 3D-printing (Cares P30) showed the most discrepancies with yellow and red (positive discrepancies) in most areas, and Group 1 - Milling (Wax) showed the best and most uniform surface matching with the most area in green.

CONCLUSION

The manufacturing technologies significantly affected the trueness and precision of occlusal splints at both intaglio and cameo surfaces. The 5-axis milling units and industrial-level CLIP 3D-printer could be considered to achieve surface accuracy of occlusal splints.

Efficacy of Mandibular Advancement Device in the Treatment of Obstructive Sleep Apnoea by Evaluating Upper Airway Space Volume Using CBCT

OBJECTIVE

To evaluate the efficacy of mandibular advancement device as a treatment of mild to moderate obstructive sleep apnoea and to evaluate the change in upper airway space volume by using cone beam CT (CBCT).

STUDY DESIGN

In vivo observational study. Place and Duration of the Study: Department of Prosthodontics, Crown and Bridge, Sri Aurobindo College of Dentistry, Indore (M.P), India, from March 2017 to January 2021.

METHODOLOGY

Patients with mild to moderate obstructive sleep apnoea patients using Berlin questionnaire were selected. Pre- and posttreatment-CBCT analysis was done to compare the changes in superior and inferior upper airway space before and after using mandibular advancement device. The pre and postoperative CBCT were also compared using a paired t-test for the quantitative variables. After two months, the patients were asked to complete a self-administered questionnaire to assess their sleep improvement, initial symptoms regression, and effectiveness of the mandibular advancement device.

RESULTS

On comparative evaluation of the pre- and post-CBCT, the mean score before the mandibular advancement device placement was found to be 7.77+2.79 cc, whereas the mean score after the mandibular advancement device placement was found to be 9.75+3.34 cc (p<0.001). Significant volumetric change was seen in upper airway space after receiving treatment for the two months. The patient noticed a substantial improvement in their sleep as well as a reduction in the original symptoms.

CONCLUSION

This study showed statistically significant volumetric change in the upper airway space and reduction in their symptoms after treatment with the mandibular advancement device (MAD).

KEY WORDS

Obstructive sleep apnoea syndrome (OSA), Continuous positive airway pressure (CPAP), Cone beam computed tomography, Mandibular advancement device (MAD), Upper airway volume.

Evaluation of flexible three-dimensionally printed occlusal splint materials: An in vitro study

OBJECTIVE

To evaluate and compare the mechanical properties, water sorption, water solubility, and degree of double bond conversion of three different commercially available three-dimensional (3D) printing resins used for the fabrication of flexible occlusal splints.

METHODS

A digital printer was used to generate specimens from the evaluated splint materials (KeySplint Soft, IMPRIMO LC Splint flex, and V-Print splint comfort). The specimens were equally divided and tested either dry or after water storage at 37 °C for 30 days. A three-point bending test was used to assess flexural strength, elastic modulus, and fracture toughness. A two-body wear test was performed using a dual-axis chewing simulator. Water sorption and water solubility were measured after 30 days. The degree of double bond conversion was determined by FTIR-spectrometry. All data for the evaluated properties were collected and statistically analyzed.

RESULTS

Both material and storage conditions had a significant effect on the flexural strength (P < 0.001), elastic modulus (P < 0.001), fracture toughness (P < 0.001), and wear (P < 0.001). The highest water sorption was noticed with IMPRIMO LC Splint flex (1.9 ± 0.0 %), while V-Print splint comfort displayed the lowest water solubility (0.2 ± 0.0 %). For the degree of conversion, it was statistically non-significant among the different materials (P = 0.087).

SIGNIFICANCE

Different flexible 3D-printed splints available in the market displayed variations in the evaluated properties and clinicians should consider these differences when choosing occlusal device materials. Among the tested flexible splint materials, KeySplint Soft had the greatest flexural strength, elastic modulus, fracture toughness, wear resistance, and degree of conversion. It also showed the lowest water sorption.

3D Printing of Thermoflexible Therapeutic Splints: Treating Bruxism More Comfortably

Three-dimensional (3D) printing has helped drive rapid and abundant growth in the field of digital dentistry and has been largely spurred on by the development of material innovation. Thermoflexible occlusal splints represent a recent innovation in this area, as they feature a remarkably elastic behavior. Now, practitioners can provide patients with a comfortable, soft, class II medical device generated through a simple digital workflow. This article presents a case report that demonstrates the management of temporomandibular joint disorders by means of a flexible 3D-printed splint. Providing the patient relative comfort while wearing the splint to prevent the negative effects of bruxism helped enhance patient acceptance and compliance. The simple, non-invasive splint fabrication described in this report can be performed by any clinicians willing to incorporate occlusal devices into their digital workflow.

Temporomandibular joint disc repositioning and occlusal splint for adolescents with skeletal class II malocclusion: a single-center, randomized, open-label trial

BACKGROUND

Temporomandibular joint (TMJ) disc repositioning through open suturing (OSu) is a new disc repositioning method. Its result for adolescents with condylar resorption and dentofacial deformities combined with and without postoperative occlusal splints (POS) has not been well studied.

OBJECTIVE

This study was to evaluate and compare the effects of OSu with and without POS in the treatment of TMJ anterior disc displacement without reduction (ADDwoR) in adolescent skeletal Class II malocclusion.

METHODS

A total of 60 adolescents with bilateral ADDwoR were enrolled in this study. They were randomly allocated into two groups: OSu with and without POS. Magnetic resonance imaging (MRI) and lateral cephalometric radiographs were used to measure changes in condylar height and the degree of skeletal Class II malocclusion from before operation and at 12 months postoperatively. Changes in these indicators were compared within and between the two groups.

RESULTS

After OSu, both groups exhibited significant improvements in condylar height and occlusion at the end of 12 months follow-up (P < 0.05). The group of OSu with POS had significantly more new bone formation (2.83 ± 0.75 mm vs. 1.42 ± 0.81 mm, P < 0.001) and improvement in dentofacial deformity than the group of OSu only (P < 0.05). The new bone height was significantly correlated with POS (P < 0.001), the changes of SNB (P = 0.018), overjet (P = 0.012), and Wits appraisal (P < 0.001).

CONCLUSION

These findings indicated that OSu can effectively stimulate condylar regeneration and improve skeletal Class II malocclusion in adolescents with bilateral ADDwoR. The results are better when combined with POS.

TRIAL REGISTRATION

This trial was prospectively registered on the chictr.org.cn registry with ID: ChiCTR1900021821 on 11/03/2019.

Effects of mandibular advancement devices on upper airway dimensions in obstructive sleep apnea: responders versus non-responders

STUDY OBJECTIVES

To compare the effects of mandibular advancement device (MAD) therapy on upper airway dimensions between responders and non-responders with mild to moderate obstructive sleep apnea (OSA).

METHODS

Thirty-one participants (21 men and 10 women) with a mean ± SD apnea-hypopnea index (AHI) of 16.6 ± 6.7 events/h, and aged 48.5 ± 13.9 years, were included in this study. Polysomnographic recordings and cone beam computed tomography (CBCT) scans in supine position were performed for every participant at baseline and at 3-month follow-up with their MAD in situ. Responders were defined as having ≥ 50% reduction in baseline AHI with a residual AHI < 10 events/h. The primary outcome variable was the minimal cross-sectional area of the upper airway (CSAmin).

RESULTS

No significant differences were found between responders (n = 15) and non-responders (n = 16) in age, gender distribution, body mass index, and neck circumference (P = 0.06-0.93), nor in AHI and CSAmin (P = 0.40 and 0.65, respectively) at baseline. The changes of the CSAmin with MAD in situ in the responder group were not significantly different compared to those in the non-responder group (P = 0.06).

CONCLUSION

Within the limitations of this study, we conclude that the changes of the upper airway dimensions induced by MADs are not significantly different between responders and non-responders with mild to moderate OSA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02724865. https://clinicaltrials.gov/ct2/show/NCT02724865.

Effect of offset on the precision of 3D-printed orthognathic surgical splints

OBJECTIVE

This study evaluated the effect of offset on the precision of three-dimensional (3D)-printed splints, proposing to optimize the splint design to compensate for systematic errors.

MATERIALS AND METHODS

14 resin model sets were scanned and offset as a whole by given distances (0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, and 0.40 mm). Intermediate splints (ISs) and final splints (FSs) were generated from the non-offset and offset models and grouped correspondingly, named as splint type-offset value, IS-0.05, for instance. Dentitions occluded with the splint were scanned. Translational and rotational deviations of the lower dentition relative to the upper dentition were 3D measured.

RESULTS

Deviations of ISs and FSs were more evident in the vertical and pitch dimensions, and were mostly acceptable in other dimensions. ISs with offset ≥ 0.05 mm showed vertical deviations significantly below 1 mm (P < 0.05) while ISs with 0.10- to 0.30-mm offsets had pitch rotations significantly lower than 1° (P < 0.05). The Pitch of IS-0.35 was significantly larger than ISs with 0.15- to 0.30-mm offsets (P < 0.05). Meanwhile, FSs fit better as the offset increased and FSs with offsets ≥ 0.15 mm all had deviations significantly lower than 1 mm (for translation) or 1° (for rotation) (P < 0.05).

CONCLUSIONS

Offset affects the precision of 3D-printed splints. Moderate offset values of 0.10 to 0.30 mm are recommendable for ISs. Offset values ≥ 0.15 mm are recommended for FSs in cases with stable final occlusion.

CLINICAL RELEVANCE

This study found the optimal offset ranges for 3D-printed ISs and FSs via a standardized protocol.