Peter Wetselaar

The Prevalence of Tooth Wear in the Dutch Adult Population

This study aimed to assess the prevalence of tooth wear in different age groups of the Dutch adult population and to determine this tooth wear distribution by gender, socioeconomic class, and type of teeth. Results were compared with the outcomes of a previous study in a comparable population. As part of a comprehensive investigation of the oral health of the general Dutch adult population in 2013, tooth wear was assessed among 1,125 subjects in the city of ‘s-Hertogenbosch. The data collected were subjected to stratified analysis by 5 age groups (25-34, 35-44, 45-54, 55-64, and 65-74 years), gender, socioeconomic class, and type of teeth. Tooth wear was assessed using a 5-point ordinal occlusal/incisal grading scale. The number of teeth affected was higher in older age groups. Men showed more tooth wear than women, and subjects with low socioeconomic status (low SES) showed on average higher scores than those with high SES. Tooth wear prevalence found in this study was higher in all age groups than in the previous study. The present study found prevalences of 13% for mild tooth wear and 80% for moderate tooth wear, leading to the conclusion that these are common conditions in the Dutch adult population. Severe tooth wear (prevalence 6%) may however be characterized as rare. A tendency was found for there to be more tooth wear in older age groups, in men as compared with women, in persons with lower SES, and in the present survey as compared with the previous one.

Assessment of the progression of tooth wear on dental casts.

Many methods are available for the grading of tooth wear, but their ability to assess the progression of wear over time has not been studied frequently. The aim was to assess whether the occlusal/incisal grading scale of the Tooth Wear Evaluation System (TWES) was sensitive enough for the detection of tooth wear progression from 14 to 23 years of age. A total of 120 sets of dental casts were gathered from 40 people, of whom impressions were made at 14, 18 and 23 years. The TWES was used to assess loss of clinical crown height throughout the entire dentition. There was a significant difference in the TWES scores between the three age groups on all teeth (Friedman tests; P < 0.005 in all cases). Post hoc Wilcoxon tests revealed that the difference between the scores between 14 and 18 years and between 18 and 23 was significant for most teeth. It was concluded that the TWES is sensitive enough to detect changes in tooth wear over time.

Assessment of the amount of tooth wear on dental casts and intra-oral photographs

Tooth wear is a multifactorial condition, leading to the loss of dental hard tissues. Many grading scales are available to assess the amount of tooth wear, one of which is the tooth wear evaluation system (TWES). A grading scale can be used chairside, on casts and on photographs. The aim was to test whether the grading scales of the TWES, used on casts and on photographs, resulted in comparable scores. In addition, it was tested whether these scales can be used to assess tooth wear reliably on photographs. Of 75 tooth wear patients, sets of casts and series of photographs were obtained and graded. Comparison of the grading on casts and on photographs revealed equal median values and percentiles for both occlusal/incisal grading and non-occlusal/non-incisal grading. The grading on casts and on photographs showed a high correlation for the occlusal/incisal grading and a low correlation for the non-occlusal/non-incisal grading (Spearmans rho = 0·74 and rho = 0·47; P < 0·001). Concerning the grading on photographs, the interexaminer reliability was fair-to-good (ICC = 0·41 to ICC = 0·55) while the intra-examiner reliability was fair-to-good to excellent (ICC = 0·68 to ICC = 0·86) for the occlusal/incisal grading. For the non-occlusal/non-incisal grading, the interexaminer reliability was poor to fair-to-good (ICC = 0·22 to ICC = 0·59), while the intra-examiner reliability was fair-to-good to excellent (ICC = 0·64 to ICC = 0·82). It was concluded that the scores obtained with the grading scales of the TWES on casts and on photographs are comparable. The grading scales can be used in a reliable way on photographs, which is especially the case for occlusal/incisal grading.

International consensus on the assessment of bruxism: Report of a work in progress

Summary In 2013, consensus was obtained on a definition of bruxism as repetitive masticatory muscle activity characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible and specified as either sleep bruxism or awake bruxism. In addition, a grading system was proposed to determine the likelihood that a certain assessment of bruxism actually yields a valid outcome. This study discusses the need for an updated consensus and has the following aims: (i) to further clarify the 2013 definition and to develop separate definitions for sleep and awake bruxism; (ii) to determine whether bruxism is a disorder rather than a behaviour that can be a risk factor for certain clinical conditions; (iii) to re-examine the 2013 grading system; and (iv) to develop a research agenda. It was concluded that: (i) sleep and awake bruxism are masticatory muscle activities that occur during sleep (characterised as rhythmic or non-rhythmic) and wakefulness (characterised by repetitive or sustained tooth contact and/or by bracing or thrusting of the mandible), respectively; (ii) in otherwise healthy individuals, bruxism should not be considered as a disorder, but rather as a behaviour that can be a risk (and/or protective) factor for certain clinical consequences; (iii) both non-instrumental approaches (notably self-report) and instrumental approaches (notably electromyography) can be employed to assess bruxism; and (iv) standard cut-off points for establishing the presence or absence of bruxism should not be used in otherwise healthy individuals; rather, bruxismrelated masticatory muscle activities should be assessed in the behaviour’s continuum.

A new definition of dental sleep medicine

A new definition of dental sleep medicine F. LOBBEZOO*, G. AARAB*, P . WETSELAAR*, A. HOEKEMA* ‡ , J . DE LANGE § & N. DE VRIES* ** *Department of Oral Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), MOVE Research Institute Amsterdam, University of Amsterdam and VU University Amsterdam, Amsterdam, Department of Oral and Maxillofacial Surgery, Tjongerschans Hospital, Heerenveen, Department of Oral and Maxillofacial Surgery, University Medical Center Groningen, Groningen, Department of Oral and Maxillofacial Surgery, Academic Medical Center (AMC) and Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Amsterdam, Department of Otorhinolaryngology, Head and Neck Surgery, OLVG West, Amsterdam, The Netherlands and **Department of Otorhinolaryngology, Head and Neck Surgery, Faculty of Medicine and Health Sciences, Antwerp University Hospital (UZA), Antwerp, Belgium

Bruxism in dentists’ families

Bruxism is defined as a repetitive jawmuscle activity that is characterised by clenching or grinding of the teeth and/or by bracing or thrusting of the mandible. It is indicated as either sleep bruxism or awake bruxism, depending on its circadian phenotype.1 While the jawmuscle activity as such does not justify extensive diagnosis and treatment,2 sleep bruxism that goes with severe (especially anterior) tooth wear, highintensity pain in the masticatory muscles and temporomandibular joints, or penetrating grinding noises does urge bruxists to seek dental help for their condition. During the consultation with the dentist, the oral history often touches upon the common observation that other family members grind their teeth as well, leading to the question whether or not bruxism runs in families. A recent, quasisystematic review of the literature now enables an evidencebased answer to the frequently asked question whether bruxism is hereditary: based on four family studies, five twin studies, and one DNA study, bruxism appears to be partly genetically determined.3

Parkinson's disease, temporomandibular disorders and bruxism: A pilot study

BACKGROUND Even though bruxism and Parkinsons disease (PD) share common characteristics, their relation is still not clear. Both bruxism and PD are movement disorders in addition, patients with bruxism as well as those with PD complain about musculoskeletal pain, including temporomandibular disorders (TMD) pain. OBJECTIVES Therefore, the aim of this pilot study was to gain more insight into the possible relation between bruxism and TMD on one hand and PD on the other. METHODS In total, 801 persons gave their written informed consent and agreed to participate in the study filling in a questionnaire. Complete data were collected from 708 persons (368 with PD or Parkinsonism [PR] and 340 controls) and were included in the analysis. The questionnaire included the graded chronic pain scale, the DC/TMD oral behaviour checklist, the DC/TMD symptom questionnaire and the TMD pain screener. In addition, a question about self-reported tooth wear was included. The chi-square test and independent samples t test were used for the data analysis. RESULTS Patients with PD/PR reported significantly more often bruxism during sleep and wakefulness than controls. Also, patients with PD/PR had more often possible TMD and reported a significantly higher mean pain intensity in the orofacial region than controls. There was no significant difference in complaints of jaw locking between the patient group and the control group. A tendency towards a significant association was found between PD/PR and tooth wear. CONCLUSION There is a relation between PD/PR and bruxism. Furthermore, a relation of PD/PR with TMD pain is suggested to be present.