Table 2.

Description of used tools to diagnose tooth wear and the various dental sleep disorders

Condition	Assessment tool
Tooth wear	To assess tooth wear, qualification and quantification are necessary. Qualification (recognise and distinguish between the different sub‐forms of tooth wear) is difficult and in the majority of the studies not performed. Regarding the qualification of tooth wear, there is no consensus at this time, although several proposals exists (Wetselaar & Lobbezoo2; Gandara & Truelove4; Ganss & Lussi 5). Quantification (grading the severity of tooth wear) is performed in more than a hundred different ways, with an equal number of different indices or evaluation systems, also here no consensus (Wetselaar & Lobbezoo2; Wetselaar et al6; Margaritis & Nunn81; Schlueter & Luka82)
Oro‐facial pain	In this narrative overview dental pain or hypersensitivity and TMD pain were eventually associated with tooth wear. Since pain is a subjective experience, dental pain or hypersensitivity were assessed by oral history taking, questionnaires, several dental tests and the use of an index, the Cumulative Hypersensitivity Index (CHI) (West et al17; Burnett et al18; Wazani et al19; Olley et al20; Macfarlane et al21)
	TMD pain was assessed using the Research Diagnostic Criteria for Temporomandibular Disorders (Dworkin & LeResche 83; Schierz et al22; Seligman & Pullinger 23)
Oral dryness	Hyposalivation can be determined by quantifying the unstimulated or stimulated whole saliva (sialometry). Since there is a great variability in individual salivary flow rates and a wide range of flow rate is accepted, the accurate assessment of dysfunction can be difficult; with this in mind it can be argued if measurement of salivary flow rates can be used as a discriminating tool (Löfgren et al27). In addition a wide variety of tests are available, like secretion tests (sialometry, sialochemistry, oral Schirmer's test, and so on), mucosal/surface test, functional tests, glandular morphology (scintigraphy or sialography), and questionnaires or interviews (Löfgren et al27; Thomson et al84)
Gastroesophageal reflux disease (GERD)	Gastroesophageal reflux disease is a complex disease with a heterogenous symptom profile. Assessment is performed by clinical history taking, questionnaires, and response to antisecretory therapy, and different tools, like endoscopy, pH monitoring (wire or wireless 24, 48, and 96 h), and/or multichannel intraluminal impedance‐pH (Gyawali et al85). All the assessment tools have their limitations because there are no universal cut‐off criteria (Vakil et al80; Gyawali et al85). Additional signs and symptoms must be present, like heartburn, regurgitation, chest pain, chronic cough and hoarseness as mentioned in the Montreal definition (Vakil et al80)
Obstructive sleep apnoea syndrome (OSAS)	The diagnosis of OSAS requires the combined assessment of the objective demonstration of abnormal breathing during sleep and relevant clinical features (signs and symptoms). The golden standard for diagnosing the objective abnormal sleep is a polysomnography (at home or in a sleep laboratory), after which the severity is determined by calculating the Apnoea‐Hypopnea index. It is possible to distinguish between Positional (POSAS) and non‐positional OSAS, some determine the amount of Respiratory Effort Related Arousals, some determine the Upper Airway Resistance Syndrome. Additional by a drug‐induced sleep/sedation endoscopy, the obstruction sites can be determinate
	Relevant clinical features (signs and symptoms) during sleep are snoring, witnessed apnoea by the bedpartner, choking or gasping, recurrent awakenings and insomnia. During wakefulness these are daytime sleepiness, unrefreshing sleep, fatigue, memory/concentration impairment, personality changes, morning nausea, and morning headaches. Structured interviewing and/or questionnaires can reveal these clinical features (American Academy of Sleep Medicine Task Force, Sleep 45)
Sleepbruxism	Sleepbruxism can be assessed non‐instrumental or instrumental. Non‐instrumental means@Non‐instrumental approaches includes self‐report (questionnaires, oral history) and clinical inspection. No consensus is present regarding these approach. Instrumental approaches are electromyographic recordings (including other measures used in somnography or polysomnography; audio and/or video recordings can supplement EMG data)@No consensus is present regarding cut‐off points of the findings@The grading system is as follows: (a) possible sleep bruxism is based on a positive self‐report only; (b) probable sleep bruxism is based on a positive clinical inspection, with or without a positive self‐report; (c) definite sleep bruxism is based on a positive instrumental assessment, with or without a positive self‐report and/or a positive clinical inspection (Lobbezoo et al56)