Ergonomic Analysis of Dental Work in Different Oral Quadrants: A Motion Capture Preliminary Study among Endodontists.

BACKGROUND: Dentists, including endodontists, frequently experience musculoskeletal disorders due to unfavourable working postures. Several measures are known to reduce the ergonomic risk; however, there are still gaps in the research, particularly in relation to dental work in the different oral regions (Quadrants 1-4). METHODS: In this study (of a pilot character), a total of 15 dentists (8 male and 7 female) specialising in endodontics were measured while performing root canal treatments on a phantom head. These measurements took place in a laboratory setting using an inertial motion capture system. A slightly modified Rapid Upper Limb Assessment (RULA) coding system was employed for the analysis of kinematic data. The significance level was set at p = 0.05. RESULTS: The ergonomic risk for the entire body was higher in the fourth quadrant than in the first quadrant for 80% of the endodontists and higher than in the second quadrant for 87%. For 87% of the endodontists, the ergonomic risk for the right side of the body was significantly higher in the fourth quadrant compared to the first and second quadrant. The right arm was stressed more in the lower jaw than in the upper jaw, and the neck also showed a greater ergonomic risk in the fourth quadrant compared to the first quadrant. CONCLUSION: In summary, both the total RULA score and scores for the right- and lefthand sides of the body ranged between 5 and 6 out of a possible 7 points. Considering this considerable burden, heightened attention, especially to the fourth quadrant with a significantly higher ergonomic risk compared to Quadrants 1 and 2, may be warranted.

Clinical parameters and inflammatory biomarkers among patients with multibracket appliances: a prospective clinical trial.

BACKGROUND: Aim of the presented study was to investigate changes in clinical parameters and active matrix metalloproteinase-8 (aMMP-8) levels in gingival crevicular fluid of patients before and during treatment with multibrackets appliances. METHODS: Fifty-five adolescents scheduled for the treatment were included. Clinical parameters and subgingival samples were obtained at six time points: 1 week before appliance insertion (T0), 3 (T1), 6 (T2) weeks, 3 (T3), 6 (T4) months, and 1 year (T5) after that. Gingival index and plaque index were assessed to evaluated changes on the clinical status. Subgingival samples were collected to analyze changes in aMMP-8. RESULTS: Scores for gingival and plaque index increased after bracket insertion. The gingival index increased from T2 (p < 0.05) until T5 (p < 0.0001). Plaque index also increased, reaching its maximum peak at T3 (p < 0.05). Moreover, an increase of aMMP-8 levels (p < 0.05) was noted. There was no significant between upper and lower jaws. CONCLUSIONS: Treatment with multibracket appliances in adolescents favors dental plaque accumulation and may transitionally increase gingival and plaque index and aMMP-8 levels leading to gingival inflammation, even 1 year after therapy began. TRIAL REGISTRATION: This study was approved by the Ethics Committee of the dental medical association Rheiland-Pfalz, Germany (process no. 837.340.12 (8441-F)), and followed the guidelines of Good Clinical Practices.

Effect of the antirheumatic medication methotrexate (MTX) on biomechanical compressed human periodontal ligament fibroblasts (hPDLFs).

BACKGROUND: The aim of this study was to investigate the in vitro effect of the antirheumatic drug methotrexate (MTX) on biomechanically compressed human periodontal ligament fibroblasts (hPDLFs), focusing on the expression of interleukin 6 (IL-6), as its upregulation is relevant to orthodontic tooth movement. METHODS: Human PDLFs were subjected to pressure and simultaneously treated with MTX. Cell proliferation, viability and morphology were studied, as was the gene and protein expression of IL-6. RESULTS: Compared with that in untreated fibroblasts, IL-6 mRNA expression in mechanically compressed ligament fibroblasts was increased (two to sixfold; ****p < 0.0001). Under compression, hPDLFs exhibited a significantly more expanded shape with an increase of cell extensions. MTX with and without pressure did not affect IL-6 mRNA expression or the morphology of hPDLFs. CONCLUSION: MTX has no effect on IL-6 expression in compressed ligament fibroblasts.

Orthodontists' instructions for oral hygiene in patients with removable and fixed orthodontic appliances.

INTRODUCTION: The aim of this questionnaire-based survey was to evaluate information on frequencies, instructions and products relating to oral hygiene (OH) in orthodontic practices. METHODS: Using a computer-generated randomization list, 1000 orthodontists were selected and sent a questionnaire. The size and number of inhabitants of the federal states of Germany were considered. The federal states with the highest return rate (Baden-Wuerttemberg [BW], Bavaria [B], Hesse [H], Lower Saxony [LS], Nordrhein-Westphalia [NRW]) were considered and differences between the 16 federal states were divided into North, South, East and Central Germany. RESULTS: The response rate of the questionnaires was 52.4%. The majority (53.8%) worked in one practice alone. Most (59.1%) have been orthodontists for 5-25 years. For vestibular multibracket appliances (MBA) in BW, B, H and LS over 90% recommended interdental brushes (IDB). In NRW 91.4% recommend fluoride gel. In B and H more than 80% chose electric toothbrush (ETB), in BW, LS and NRW more than 80% manual toothbrush (MTB). For lingual MBA (LMBA) in BW, H, LS and NRW with approximately 50% each fluoride gel, IDB and MTB were chosen. In B fluoride gel, IDB and ETB. For removable apparatus (RA), five federal states recommended MTB (>80%) and ETB (BW, B, H > 80%; NRW > 70%; LS > 60%). CONCLUSION: Electric toothbrushes are recommended for the use with all appliances, only with removable appliances manual toothbrushes are favoured. For vestibular MBA it is strongly advised to use IDB additionally.

Randomized multicenter study on the plaque removal efficacy of 2 interdental brushes around the base of orthodontic brackets.

INTRODUCTION: The objective of this multicenter study was to analyze the efficacy of cleaning 2 interdental brushes (IDBs) around brackets in patients with fixed orthodontic appliances. METHODS: The study design was a multicenter, randomized, examiner-blinded crossover study with 3 interventions, the first of which was a baseline intervention. This study included 20 patients (12 females, 8 males) aged 12-18 years with fixed orthodontic devices examined at the Department of Orthodontics, University Medical Center of the Johannes Gutenberg University Mainz, and the Children's Dental Clinic St. Gallen. The outcome was a conventional, cylindrically shaped IDB (IDBG-S [IB]; Top Caredent GmbH, Schönau, Germany) was examined in comparison with an innovative waist-shaped IDB (Circum, CDB-8 [CB]; Top Caredent GmbH). The participants did not use the IDB themselves. The brushing procedure was performed professionally by 1 operator (C.E.). Each buccal tooth surface with a bracket was split into 8 areas, the main areas being 1 and 8. These main areas, which were difficult for toothbrushes to reach, were mesial (area 1) and distal (area 8) of the bracket edges in the gingival direction. Plaque index (PI) scores were assessed at 2 examinations before and after the cleaning procedure on 8 tooth surfaces in the area with orthodontic brackets. A computer-generated program randomly allocated the IDB sequence to the participants. Examiners (L.Z.-G. and Y.W.) assessing the outcomes were blinded to the intervention and the randomized allocation of participants to the different IDBs. RESULTS: Both IDBs showed a plaque removal effect (CB, 0.68 [interquartile range, 0.63-0.77]; IB, 0.43 [interquartile range, 0.33-0.55]). The difference between the 2 IDB was statistically significant (P = 0.002). In particular, the CB yielded a higher plaque removal efficacy (CB effect, 0.68; IB effect, 0.21) at the main areas 1 and 8, which were difficult to reach. Ten participants were randomized to each sequence, and all 20 completed the study. No side effects or adverse events were reported or observed. CONCLUSION: The waist-shaped brush head of the CB significantly enhanced plaque reduction in total and particularly in problem areas. REGISTRATION: This trial was registered at the German Clinical Trials Registry (no. DRKS00014088; https://www.drks.de/drks_web/navigate.xxdo?navigationId=trial.HTML&TRIAL_ID=DRKS00014088) PROTOCOL: The protocol was not published before trial commencement. FUNDING: This study was supported by the manufacturer Top Caredent GmbH, Schönau, Germany, which provided all interdental brushes used in this study.

Testing the Level of Agreement between Two Methodological Approaches of the Rapid Upper Limb Assessment (RULA) for Occupational Health Practice-An Exemplary Application in the Field of Dentistry.

BACKGROUND: The Rapid Upper Limb Assessment (RULA) is used for the risk assessment of workplace-related activities. Thus far, the paper and pen method (RULA-PP) has been predominantly used for this purpose. In the present study, this method was compared with an RULA evaluation based on kinematic data using inertial measurement units (RULA-IMU). The aim of this study was, on the one hand, to work out the differences between these two measurement methods and, on the other, to make recommendations for the future use of the respective method on the basis of the available findings. METHODS: For this purpose, 130 (dentists + dental assistants, paired as teams) subjects from the dental profession were photographed in an initial situation of dental treatment and simultaneously recorded with the IMU system (Xsens). In order to compare both methods statistically, the median value of the difference of both methods, the weighted Cohen's Kappa, and the agreement chart (mosaic plot) were applied. RESULTS: In Arm and Wrist Analysis-area A-here were differences in risk scores; here, the median difference was 1, and the agreement in the weighted Cohen's kappa test also remained between 0.07 and 0.16 (no agreement to poor agreement). In area B-Neck, Trunk, and Leg Analysis-the median difference was 0, with at least one poor agreement in the Cohen's Kappa test of 0.23-0.39. The final score has a median of 0 and a Cohen's Kappa value of 0.21-0.28. In the mosaic plot, it can be seen that RULA-IMU had a higher discriminatory power overall and more often reached a value of 7 than RULA-PP. CONCLUSION: The results indicate a systematic difference between the methods. Thus, in the RULA risk assessment, RULA-IMU is mostly one assessment point above RULA-PP. Therefore, future study results of RULA by RULA-IMU can be compared with literature results obtained by RULA-PP to further improve the risk assessment of musculoskeletal diseases.

Ergonomic Risk Assessment of Oral and Maxillofacial Surgeons - RULA Applied to Objective Kinematic Data.

BACKGROUND: The prevalence of musculoskeletal disorders is high in oral and maxillofacial surgeons (OS) due to their static and contorted working positions. Hence, the aim of this study was to conduct posture analyses in this specific group of dental professionals using the Rapid Upper Limb Assessment (RULA). METHODS: In total, 15 (12 m/3 f) OS participated in this study. An inertial motion capture system (Xsens) was used to collect kinematic data during a simulated workflow. Computer-based routines calculated the RULA score for the extracted joint angles at each defined time point. Then, an analysis of the time-dependent RULA scores by body regions was conducted. Key variables were the relative occurrence of specific RULA scores during the complete workflow, individual subtasks, and for treatment of each of the four different dental quadrants. The subtasks and dental quadrants were compared using the Friedman test. RESULTS: The total median RULA score represented a high risk for OS during their work (7), including the temporal component (OS spent 77.54% of their working time with a RULA score of 7). The wrists and hands, elbows, lower arms, and the neck were exposed to postures with the highest risk for musculoskeletal strain. DISCUSSION: For OS, both the right and the left assisting hand were heavily strained while working on the first dental quadrant caused the most unfavorable postures for OS.

Aligner therapy in adolescents: first-year results on the impact of therapy on oral health-related quality of life and oral hygiene.

OBJECTIVES: The aim of this multicenter clinical study was to examine the oral health-related quality of life and oral hygiene in adolescents before and during aligner therapy. MATERIALS AND METHODS: Forty subjects (18 ♀, 22 ♂; mean age: 13.6 years) scheduled for aligner therapy (Invisalign® Teen) were given oral health-related quality of life questionnaires, Oral Health Impact Profile (OHIP-G14) and Psychosocial Impact of Dental Aesthetic Questionnaire (PIDAQ), to complete within their treatment (visit 1: 0 start of therapy; visit 2: 0 + 4 weeks; visit 3: 0 + 10 weeks; visit 4: 0 + 6 months; visit 5: 0 + 1 year). To assess oral hygiene, a questionnaire to take home was used, and plaque level was evaluated with the Quigley-Hein Plaque Index (TMQH) modified by Turesky et al. RESULTS: The OHIP-G14 mean score before aligner therapy was 3.3 ± 3.2, and 4.9 ± 5.4 after 1 year. The PIDAQ showed a positive psychological change in the well-being, as well as a more effective at-home oral hygiene regime. On average, the TMQH remained at a low level (grade 2 of 0-5). The initial insertion of the aligners caused the most significant changes in all parameters (except TMQH). CONCLUSION: Oral health-related quality of life is only slightly affected during the first year of aligner therapy in adolescents. Oral hygiene at home is intensified and there is no increased dental plaque accumulation. CLINICAL RELEVANCE: Dentofacial esthetics is a subset of the so-called Oral H-Related Quality of Life (OHRQoL) which should be considered more during orthodontic therapy.

Orthodontic treatment in periodontally compromised patients: a systematic review.

OBJECTIVES: The aim of this systematic review was to examine the literature on aggressive and chronic periodontitis and orthodontics to clarify the therapy-relevant aspects of orthodontic treatment with altered biomechanics in periodontally compromised dentition. MATERIALS AND METHODS: Literature searches were conducted in the electronic databases "PubMed" and "DIMDI" using the keywords "aggressive periodontitis AND ortho*," "aggressive periodontitis AND orthodontics," "chronic periodontitis AND ortho*," and "chronic periodontitis AND orthodontics" for the publication period from January 1990 to July 2022. In addition, a manual search was carried out in the selected trade journals "Community Dental Health," "European Journal of Oral Sciences," and "Parodontologie." Human clinical trials were included, whereas animal experimental studies, case reports, and reviews were generally excluded. The appropriate studies were selected, and the relevant data was tabulated according to different parameters, regarding the study design, the study structure, and the conduct of the study. RESULTS: A total of 1067 articles were found in the preliminary electronic search. The manual search and review of all related bibliographies resulted in an additional 1591 hits. After the first screening, 43 articles were classified as potentially relevant and reviewed in their original form. After the suitability test, 5 studies with a total of 366 participants were included in the final evaluation. These included one randomized controlled trial and four low-evidence intervention studies. The studies were conducted in two university hospitals and three private practices. All participants underwent scaling and root plaining and periodontal surgery before the orthodontic treatment started. Mean probing pocket depth reduction before and after the interdisciplinary treatment was analyzed in all the included studies; mean difference in clinical attachment level in four of the studies was also included. All participants were enrolled in a continuous recall system. In all studies, orthodontic therapy in periodontally compromised patients improved function and esthetics, resulting in lower probing depths and clinical attachment gains. CONCLUSIONS: Orthodontic treatment can be used for patients with reduced periodontal support to stabilize clinical findings and improve function and esthetics. The prerequisite for this is a profound knowledge of altered biomechanics and an adapted interdisciplinary treatment approach. Due to the large heterogeneity of the included studies and their limited methodological quality, the results obtained in this review must be considered critically. Further randomized controlled long-term studies with comparable study designs are necessary to obtain reliable and reproducible treatment results. CLINICAL RELEVANCE: Patients with periodontal impairment can be successfully treated with orthodontics as part of interdisciplinary therapy. Orthodontic treatment has no negative impact on the periodontium; if minimal, controlled forces are used under non-inflammatory conditions.

Comparison of different plaque indices with regard to sensitivity and specificity for the quantification of plaque during orthodontic therapy.

To compare four plaque indices used in orthodontics. An objective, quantitative plaque index and three subjective conventional plaque indices were analyzed. The study included n = 50 photographs of n = 50 subjects with a multibracket appliance (MB) in the maxilla and mandible. Photographs were taken using Digital Plaque Imaging Analysis (DPIA) and the Percentage Plaque Index (PPI) was calculated. The conventional plaque indices, a modified version of the Turesky-modification of the Quigley & Hein Index (TQH index), Attin index, and modified bonded bracket index (mBB index) were collected from n = 14 evaluators using the DPIA photographs. The evaluators had different levels of orthodontic experience: n = 4 evaluators had little orthodontic experience, n = 5 evaluators had moderate orthodontic experience, and n = 5 evaluators had a lot of orthodontic experience. Plaque accumulation was assessed differently with the plaque indices. Thus, the plaque indices are not interchangeable. We recommend DPIA as an objective, quantitative and sensitive method for plaque determination in scientific studies. The simple statistical evaluation offers a great advantage over conventional plaque indices.

Effects of Resistance Training as a Behavioural Preventive Measure on Musculoskeletal Complaints, Maximum Strength and Ergonomic Risk in Dentists and Dental Assistants.

INTRODUCTION: For dental professionals, musculoskeletal disorders (MSD) are common health hazards and resistance training programmes have been promising approaches in the quest for a reduction in the pain intensity of these professionals. Therefore, the aim of the current study was to investigate the effect of a trunk-oriented 10-week resistance training programme. METHOD: In total, the study was conducted with 17 dentists and dental assistants (3 m/14 f) over a course of 10 weeks, with workouts being performed 2 times a week using a 60 min intervention programme consisting of 11 resistance training exercises. The outcome values that were collected were the pain intensity (visual analogue scale (VAS) combined with a modified version of the Nordic Questionnaire), the MVIC and the rapid upper limb assessment (RULA) score (based on data from inertial motion units) during a standardised dental treatment protocol. RESULTS: A significant reduction in pain intensity was found for each queried body region: the neck, upper back, lower back and the right and left shoulders. The maximum voluntary isometric contraction (MVIC) improved significantly in all outcome measures: flexion, extension, right and left lateral flexion and right and left rotation. CONCLUSIONS: A 10-week resistance training programme for dentists and dental assistants had significant effects on pain intensity reduction and the MVIC of the musculature of the trunk and is, therefore, suitable as a behavioural preventive measure against MSD in dental professionals.

A RULA-Based Comparison of the Ergonomic Risk of Typical Working Procedures for Dentists and Dental Assistants of General Dentistry, Endodontology, Oral and Maxillofacial Surgery, and Orthodontics.

BACKGROUND: In general, the prevalence of work-related musculoskeletal disorders (WMSD) in dentistry is high, and dental assistants (DA) are even more affected than dentists (D). Furthermore, differentiations between the fields of dental specialization (e.g., general dentistry, endodontology, oral and maxillofacial surgery, or orthodontics) are rare. Therefore, this study aims to investigate the ergonomic risk of the aforementioned four fields of dental specialization for D and DA on the one hand, and to compare the ergonomic risk of D and DA within each individual field of dental specialization. METHODS: In total, 60 dentists (33 male/27 female) and 60 dental assistants (11 male/49 female) volunteered in this study. The sample was composed of 15 dentists and 15 dental assistants from each of the dental field, in order to represent the fields of dental specialization. In a laboratory setting, all tasks were recorded using an inertial motion capture system. The kinematic data were applied to an automated version of the Rapid Upper Limb Assessment (RULA). RESULTS: The results revealed significantly reduced ergonomic risks in endodontology and orthodontics compared to oral and maxillofacial surgery and general dentistry in DAs, while orthodontics showed a significantly reduced ergonomic risk compared to general dentistry in Ds. Further differences between the fields of dental specialization were found in the right wrist, right lower arm, and left lower arm in DAs and in the neck, right wrist, right lower arm, and left wrist in Ds. The differences between Ds and DAs within a specialist discipline were rather small. DISCUSSION: Independent of whether one works as a D or DA, the percentage of time spent working in higher risk scores is reduced in endodontologists, and especially in orthodontics, compared to general dentists or oral and maxillofacial surgeons. In order to counteract the development of WMSD, early intervention should be made. Consequently, ergonomic training or strength training is recommended.

A novel method quantifying caries following orthodontic treatment.

This retrospective pilot study used a newly developed evaluation tool to assess the prevalence and incidence of White Spot Lesions (WSL) before and after multibracket appliance (MB) therapy. Digital photographs of 121 adolescent patients (63 ♂, 58 ♀) with metal brackets were analyzed retrospectively before and after MB therapy. The labial surfaces of anterior teeth, canine teeth, and premolars in the upper (UJ) and lower jaws (LJ) were evaluated using the Enamel Decalcification Index (EDI) by Banks and Richmond (Eur J Orthod, 16(1):19-25, 1994, levels 0-3) and a specially developed digitally scaled graticule with concentric circles to quantify the extent of WSL (in %). The statistical data analysis was based on crosstabulations and logistic regression. Before MB, 69.4% of the patients presented at least one WSL and 97.5% after, an increase of 28.1%. Before MB, 18.4% of the tooth surfaces (TS) showed an EDI level of 1-3. After MB, 51.8% of the TS featured WSL. 18.2% of the TS showed a WSL to the extent of ≥ 20-100% before and 52.3% after MB. The incidence in the UJ (71-79%) as well as the LJ (64-76%) was highest for the first and second premolars and lowest for LJ incisors (22-35%). The probability for developing a new distal WSL is higher than developing gingival, mesial or occlusal WSL. Labial MB therapy drastically increases the risk of developing WSL. We verified a concise quantification of the extent of labial WSL with the evaluation index.

Ergonomic Comparison of Four Dental Workplace Concepts Using Inertial Motion Capture for Dentists and Dental Assistants.

When the inventory is arranged in a dental practice, a distinction can be made between four different dental workplace concepts (DWCs). Since the prevalence of musculoskeletal diseases in dental professionals is very high, preventive solution need to be investigated. As the conventionally used DWCs have, to date, never been studied in terms of their ergonomics, this study aims to investigate the ergonomic risk when working at the four different DWCs. In total, 75 dentists (37 m/38 f) and 75 dental assistants (16 m/59 f) volunteered to take part in this study. Standardized cooperative working procedures were carried out in a laboratory setting and kinematic data were recorded using an inertial motion capture system. The data were applied to an automated version of the Rapid Upper Limb Assessment (RULA). Comparisons between the DWCs and between the dentists and dental assistants were calculated. In all four DWCs, both dentists and dental assistants spent 95-97% of their working time in the worst possible RULA score. In the trunk, DWCs 1 and 2 were slightly favorable for both dentists and dental assistants, while for the neck, DWC 4 showed a lower risk score for dentists. The ergonomic risk was extremely high in all four DWCs, while only slight advantages for distinct body parts were found. The working posture seemed to be determined by the task itself rather than by the different inventory arrangements.

Ergonomic Risk Assessment of Dental Students-RULA Applied to Objective Kinematic Data.

Musculoskeletal disorder (MSD) is already prevalent in dental students despite their young age and the short duration of dental practice. The current findings state that the causes of MSD are related to posture during dental work. This study aims to investigate the ergonomic risk of dental students. In order to analyze the ergonomic risk of dental students, 3D motion analyses were performed with inertial sensors during the performance of standardized dental activities. For this purpose, 15 dental students and 15 dental assistant trainees (all right-handed) were measured in a team. Data were analyzed using the Rapid Upper Limb Assessment (RULA), which was modified to evaluate objective data. Ergonomic risk was found for the following body parts in descending order: left wrist, right wrist, neck, trunk, left lower arm, right lower arm, right upper arm, left upper arm. All relevant body parts, taken together, exhibited a posture with the highest RULA score that could be achieved (median Final Overall = 7), with body parts in the very highest RULA score of 7 for almost 80% of the treatment time. Dental students work with poor posture over a long period of time, exposing them to high ergonomic risk. Therefore, it seems necessary that more attention should be paid to theoretical and practical ergonomics in dental school.

Combining Ergonomic Risk Assessment (RULA) with Inertial Motion Capture Technology in Dentistry-Using the Benefits from Two Worlds.

Traditional ergonomic risk assessment tools such as the Rapid Upper Limb Assessment (RULA) are often not sensitive enough to evaluate well-optimized work routines. An implementation of kinematic data captured by inertial sensors is applied to compare two work routines in dentistry. The surgical dental treatment was performed in two different conditions, which were recorded by means of inertial sensors (Xsens MVN Link). For this purpose, 15 (12 males/3 females) oral and maxillofacial surgeons took part in the study. Data were post processed with costume written MATLAB® routines, including a full implementation of RULA (slightly adjusted to dentistry). For an in-depth comparison, five newly introduced levels of complexity of the RULA analysis were applied, i.e., from lowest complexity to highest: (1) RULA score, (2) relative RULA score distribution, (3) RULA steps score, (4) relative RULA steps score occurrence, and (5) relative angle distribution. With increasing complexity, the number of variables times (the number of resolvable units per variable) increased. In our example, only significant differences between the treatment concepts were observed at levels that are more complex: the relative RULA step score occurrence and the relative angle distribution (level 4 + 5). With the presented approach, an objective and detailed ergonomic analysis is possible. The data-driven approach adds significant additional context to the RULA score evaluation. The presented method captures data, evaluates the full task cycle, and allows different levels of analysis. These points are a clear benefit to a standard, manual assessment of one main body position during a working task.

Oral Health: Global Research Performance under Changing Regional Health Burdens.

Objectives: Inadequate oral hygiene still leads to many serious diseases all over the world. Therefore, this study aimed to analyze scientific research in the field of oral health in order to be able to comprehend their relevant subject areas, research connections, or developments. Methods: This study aimed to assess the global publication output on oral hygiene to create a world map that provides background information on key players, trends, and incentives of research. For this purpose, established bibliometric parameters were combined with state-of-the-art visualization techniques. Results: This study shows the actual key players of research on oral hygiene in high-income economies with only marginal participation from lower economies. This still corresponds to the current burden situations, but they are more and more shifting to the disadvantage of the low-income countries. There is a clear North-South and West-East gradient, with the USA and the Western European nations being the most publishing nations on oral hygiene. As an emerging country, Brazil plays a role in the research. Conclusions: The scientific power players were concentrated in high-income countries. However, the changing epidemiological situation requires a different scientific approach to oral hygiene. This requires an expansion of the international network to meet the demands of future global oral health burdens, which are mainly related to oral hygiene.

The Herbst appliance and its modifications - prevalence and individuality.

OBJECTIVE: The aim of this study was to analyze the use of modified, cast splint Herbst appliances for the treatment of skeletal class II as an alternative to surgical bite correction over a period of five years. MATERIALS AND METHODS: The patient cases all originate from the patients of the Department of Orthodontics at the University Medical Center of the Johannes Gutenberg University Mainz, Germany and the orthodontic practice Dres. Zöller, Kaiserslautern, Germany. Inclusion criteria were orthodontic treatment with the Herbst appliance and its modifications. The type of modification, number and frequency of the different modifications were determined on the basis of patient files, X-ray documents, photos and models. RESULTS: Of a total of 2881 new admissions over a period of five years, 1751 patients came from the Department of Orthodontics at the University Medical Center of the Johannes Gutenberg University Mainz and 1130 from the orthodontic practice in Kaiserslautern. A total of 336 patients were treated with a Herbst appliance during the period mentioned. 14 (13%) of the cases from the Herbst patient collective of the University Medical Center and 45 (19%) of the cases from the orthodontic practice were classified as modifications. The following modifications could be determined in descending order: University Medical Center Mainz: Herbst for anchorage during space closure (65%) > distalization (14%) ≥ bar construction as a space maintainer (14%) > Herbst applicance for anchoring for the adjustment of impacted teeth (7%); orthodontic practice Kaiserslautern: Herbst appliance with quadhelix in the maxilla (42%) > distalization (27%) > space closure (15%) > bar construction as a space maintainer (9%) > adjustment of impacted teeth (7%), multiple modifications occurred at 11%. The combination of quadhelix and Herbst appliance as well as multiple modifications have not yet been used in the University Medical Center Mainz. As an alternative to dysgnathia surgery, 23 adult patients (> 18 years) from the University Medical Center and 22 from the orthodontic practice were treated with a Herbst appliance. CONCLUSION: Nearly 12% of Herbst appliances are used in everyday orthodontic practice and almost 18% of these are used with modification(s). The high anchoring quality and force-effect geometry of the Herbst appliance is suitable for combining and treating various other treatment tasks in addition to the classical treatment task of class II therapy.

Optical analysis of the behavior of sealants under mechanical, thermal and chemical stress.

Regarding their resistance five sealants were tested in vitro after experiencing mechanical, thermal and chemical stress. Included for testing were two fluoride varnishes: Fluor Protector [FP] (Ivoclar Vivadent) and Protecto CaF2 Nano One-Step Seal [PN] (BonaDent) and three fluoride-composite filled sealants (with acid etch technique): Clinpro XT Varnish [CP] (3 M Espe), Pro Seal [PS] & Light Bond [LB] (Reliance Orthodontic Products) and a positive control group [CG] Tetric EvoFlow (Ivoclar Vivadent). The sealants were applied on 180 bovine teeth (n = 10/ sealer) in a standardized manner after bracket bonding. Mechanical pressure and its effect by simulating different time points and standardized electric cleaning protocol was tested first. Followed by thermal burden due to varying thermal stress and thirdly change in pH stress imitating chemical exposure were examined separately. A digital microscope and a grid incisal and apical to the brackets (n = 32 fields) was used to standardize the optical analysis. Material loss due to mechanical stress compared to CG (score 0.00) was CP (1.2%), FP (21.5%), LB (22.2%) and PN (81.1%). No significant difference to CG presented PS. Material loss due to thermal stress was CP (0.5%), PS (2%), FP (2.6%), LB (3.1%) and PN (39.9%). Material loss due to chemical stress was FP (1.8%), PS (2.1%), LB (5.5%) and PN (39.6%). No significant difference to CG presented CP. Only PS and CP had optically provable, good resiliance to mechanical, thermal and chemical stress. Significantly poorer outcomes in particular showed PN.

Prevalence of Musculoskeletal Disorders among Dentists and Dental Students in Germany.

BACKGROUND: Dentists are at a higher risk of suffering from musculoskeletal disorders (MSD) than the general population. However, the latest study investigating MSD in the dental profession in Germany was published about 20 years ago. Therefore, the aim of this study was to reveal the current prevalence of MSD in dentists and dental students in Germany. METHODS: The final study size contained 450 (287 f/163 m) subjects of different areas of specialization. The age of the participants ranged from 23 to 75 years. The questionnaire consisted of a modified version of the Nordic Questionnaire, work-related questions from the latest questionnaire of German dentists, typical medical conditions and self-developed questions. RESULTS: The overall prevalence showed that dentists suffered frequently from MSD (seven days: 65.6%, twelve months: 92%, lifetime: 95.8%). The most affected body regions included the neck (42.7%-70.9%-78.4%), shoulders (29.8%-55.6%-66.2%) and lower back (22.9%-45.8%-58.7%). Overall, female participants stated that they suffered from pain significantly more frequently, especially in the neck, shoulders and upper back. CONCLUSION: The prevalence of MSD among dentists, especially in the neck, shoulder and back area, was significantly higher than in the general population. In addition, women suffered more frequently from MSD than men in almost all body regions.