Dick J. Witter

Tooth loss and oral health-related quality of life: a systematic review and meta-analysis

BackgroundIt is increasingly recognized that the impact of disease on quality of life should be taken into account when assessing health status. It is likely that tooth loss, in most cases being a consequence of oral diseases, affects Oral Health-Related Quality of Life (OHRQoL). The aim of the present study is to systematically review the literature and to analyse the relationship between the number and location of missing teeth and oral health-related quality of life (OHRQoL). It was hypothesized that tooth loss is associated with an impairment of OHRQoL. Secondly, it was hypothesized that location and distribution of remaining teeth play an important role in this.MethodsRelevant databases were searched for papers in English, published from 1990 to July 2009 following a broad search strategy. Relevant papers were selected by two independent readers using predefined exclusion criteria, firstly on the basis of abstracts, secondly by assessing full-text papers. Selected studies were grouped on the basis of OHRQoL instruments used and assessed for feasibility for quantitative synthesis. Comparable outcomes were subjected to meta-analysis; remaining outcomes were subjected to a qualitative synthesis only.ResultsFrom a total of 924 references, 35 were eligible for synthesis (inter-reader agreement abstracts κ = 0.84 ± 0.03; full-texts: κ = 0.68 ± 0.06). Meta-analysis was feasible for 10 studies reporting on 13 different samples, resulting in 6 separate analyses. All studies showed that tooth loss is associated with unfavourable OHRQoL scores, independent of study location and OHRQoL instrument used. Qualitative synthesis showed that all 9 studies investigating a possible relationship between number of occluding pairs of teeth present and OHRQoL reported significant positive correlations. Five studies presented separate data regarding OHRQoL and location of tooth loss (anterior tooth loss vs. posterior tooth loss). Four of these reported highest impact for anterior tooth loss; one study indicated a similar impact for both locations of tooth loss.ConclusionsThis study provides fairly strong evidence that tooth loss is associated with impairment of OHRQoL and location and distribution of tooth loss affect the severity of the impairment. This association seems to be independent from the OHRQoL instrument used and context of the included samples.

Oral health status of adults in Southern Vietnam - a cross-sectional epidemiological study

BackgroundBefore strategies or protocols for oral health care can be advised at population level, epidemiological information on tooth decay patterns and its effects on oral function are indispensable. The aim of this study was to investigate influences of socio-demographic variables on the prevalence of decayed, missing, filled (DMF) and sound teeth (St) and to determine the relative risk of teeth in different dental regions for D, M, and F, of adults living in urban and rural areas in Southern Vietnam.MethodsCross-sectional DMF and St data of 2965 dentate subjects aged 20 to 95 living in urban and rural areas in three provinces were collected by means of a self-administered questionnaire and an oral examination. The sample was stratified by age, gender, residence and province.ResultsThe percentage of subjects having missing teeth was high for all ages while it was low for subjects with decayed and filled teeth. The mean number of missing teeth increased gradually by age from approximately 1 in each jaw at the age of 20 to 8 at the age of 80. The number of decayed teeth was relative low at all ages, being highest in molars at young ages. The mean number of filled teeth was extremely low at all ages in all dental regions. Every additional year of age gives a significantly lower chance for decay, a higher chance for missing, and a lower chance for filled teeth. Molars had a significantly higher risk for decay, missing and filled than premolars and anterior teeth. Females had significantly higher risk for decayed and filled teeth, and less chance for missing teeth than males. Urban subjects presented lower risk for decay, but approximately 4 times greater chance for having fillings than rural subjects. Low socio-economic status (SES) significantly increased the chance for missing anterior and molar teeth; subjects with high SES had more often fillings.ConclusionsThe majority of adults of Southern Vietnam presented a reduced dentition. The combination of low numbers of filled teeth and relative high numbers of decayed and missing teeth indicates that the main treatment for decay is extraction. Molars are more at risk for being decayed or missing than premolars and anterior teeth.

Clinical interpretation of a masticatory normative indicator analysis of masticatory function in subjects with different occlusal and prosthodontic status

OBJECTIVESnTo analyse the masticatory function of subjects characterised by different occlusal and prosthodontic status. Using Optosil(®) as a test food, the masticatory normative indicator (MNIOPT) was used to differentiate between sufficient (normal) and impaired masticatory function.nnnMETHODSnOutcomes of occlusal force and masticatory tests were aggregated from three earlier studies dealing with four denture groups and three natural dentition groups. The four denture groups had a complete removable dental prosthesis in the upper jaw, and displayed one of the four following lower jaw prosthodontic rehabilitations: (i) complete removable dental prosthesis on a low mandible; (ii) complete removable dental prosthesis on a higher mandible; (iii) overdenture on natural roots; and (iv) overdenture on dental implants. The three natural dentition groups were: (i) shortened dental arch; (ii) complete dentition in older participants, and (iii) complete dentition in younger participants. All participants were women. They performed the same tests twice, and outcomes were averaged.nnnRESULTSnA MNIOPT value of 3.68 mm was determined from the participants with complete natural dentitions. Applying the MNIOPT to the participants in the denture groups pointed at a considerable chance for impaired masticatory function, except for participants in the overdenture -implants group. The four denture groups compensated for reduced masticatory efficiency by increased number of masticatory cycles and prolonged mastication time until swallowing. Nevertheless, they also swallowed larger particles compared to the complete dentition group.nnnCLINICAL SIGNIFICANCEnFor a given patient or for a group of subjects with specific dental conditions, MNI enables to discriminate between a sufficient (normal) and an impaired masticatory function.

Chewing ability in an urban and rural population over 40 years in Shandong Province, China

ObjectivesThis study aimed to assess chewing ability related to dental status.Material and methodsOne thousand four hundred sixty-two Chinese subjects over 40xa0years, dentate in both jaws, were categorized in a hierarchical functional classification system with and without tooth replacements. Chewing ability was analyzed using multivariable logistic regression including five dental conditions (≥10 teeth in each jaw’; ‘complete anterior regions’; “sufficient premolar regions’ (≥3 posterior occluding pairs (POPs)); ‘sufficient molar regions’ (bilaterally ≥1 POP); and tooth replacement), adjusted for six background variables. Likelihood ratios for chewing problems were assessed at each level of the hierarchical classification system based on these dental conditions.ResultsSeventy-eight to 91xa0% of subjects reported no or minor chewing problems. The conditions ‘≥10 teeth in each jaw’, and ‘complete anterior regions’ were not associated, whereas ‘sufficient’ premolar regions’ and ‘sufficient molar regions’ were associated with chewing problems (Ors, 0.33–0.58). If classified hierarchically, the condition ‘≥10 teeth in each jaw’ was relevant for chewing problems (likelihood ratios 3.3–3.7). ‘Sufficient premolar region’ and ‘sufficient molar region’ were relevant to reduce the likelihood ratios for having chewing problems (both approximately with a factor 2), both for soft and for hard foods. Subjects with artificial teeth added had similar chance for chewing problems compared to counterparts with natural teeth only. However, if comparing replaced teeth with natural teeth, subjects with tooth replacement showed higher chance for chewing problems.ConclusionsChewing ability was strongly associated with dental conditions.Clinical relevanceThe presence of at least 10 teeth in each jaw had highest impact on chewing ability.

An observational cohort study on shortened dental arches--clinical course during a period of 27-35 years.

ObjectivesThe objective of this study was to investigate the clinical course of shortened dental arches (‘SDA group’) compared to SDAs plus removable denture prosthesis (‘SDA plus RDP group’) and complete dental arches (‘CDA group’, controls).Materials and methodsData (numbers of direct and indirect restorations, endodontic treatments, tooth loss and tooth replacements) were extracted from patient records of subjects attending the Nijmegen Dental School who previously participated in a cohort study on shortened dental arches with three to four posterior occluding pairs (POPs).ResultsRecords of 35xa0% of the original cohort were retrievable. At the end of the follow-up (27.4u2009±u20097.1xa0years), 20 out of 23 SDA subjects still had SDA with 3–4 POPs compared to 6 out of 13 for SDA plus RDP subjects (follow-up 32.6u2009±u20097.3xa0years). Sixteen out of 23 CDA subjects still had CDA; none of them lost more than one POP (follow-up 35.0u2009±u20095.6xa0years). SDA group lost 67 teeth: 16 were not replaced, 16 were replaced by FDP and 35 teeth (lost in three subjects) replaced by RDP. Mean number of treatments per year in SDA subjects differed not significantly compared to CDA subjects except for indirect restorations in the upper jaw.ConclusionShortened dental arches can last for 27xa0years and over. Clinical course in SDA plus RDP is unfavourable, especially when RDP-related interventions are taken into account.Clinical relevanceThe shortened dental arch concept seems to be a relevant approach from a cost-effective point of view. Replacement of absent posterior teeth by free-end RDP cannot be recommended.

Effects of removable dental prostheses on masticatory performance of subjects with shortened dental arches: A systematic review

OBJECTIVEnTo synthesise data on the effects of distal-extension removable dental prostheses (RDPs) on masticatory performance of subjects with (extreme) shortened dental arches ((E)SDAs).nnnDATAnSearch terms were: masticatory respectively chewing combined with performance, efficiency, or ability.nnnSOURCESnAn electronic search restricted to the years 2003-2014 in PubMed, Medline, Cochrane Library, Embase, and Science Direct databases.nnnSTUDY SELECTIONnStudies exposing data on subjects with SDA (3-5 posterior occluding pairs) or ESDA (0-2 posterior occluding pairs) and on masticatory performance with RDP were included.nnnRESULTSnFour studies provided data on comminution, three on mixing ability, and one on both tests. Comminution or mixing ability in subjects with (E)SDA was 28-39% lower compared to that of subjects with complete dentitions. In two studies, comminution outcomes when chewing with an RDP ranged from 2% to 32% reduction, indicating better chewing function (smaller X50) compared to comminution without the RDP. One study reported 28-83% lower mixing ability when chewing at the RDP side than chewing at the dentulous side. Generally, more artificial teeth (or longer occlusal platform) in experimental RDPs resulted in better comminution and better mixing ability (significant in four out of five studies), indicating a dose-effect relationship.nnnCONCLUSIONSn(1) Subjects with (E)SDA had a 30-40% reduced masticatory performance; (2) distal-extension RDPs could compensate this reduction partially (some 50%); and (3) more artificial teeth in RDPs resulted in better performance.nnnCLINICAL SIGNIFICANCEnDistal-extension RDPs in subjects with SDA partially compensate reduced masticatory performance.

Dental and prosthodontic status of an over 40 year-old population in Shandong Province, China.

BackgroundThis study aims to (1) describe the dental status using DMFT for the whole dentition and the anterior, premolar and molar regions; (2) determine associations of demographic variables and socio-economic status (SES) with DMFT and tooth replacement; (3) analyze to what extent the goal as proposed by the WHO -the retention of not less than 20 teeth throughout life is achieved.MethodsDMFT and tooth replacement data of 1588 subjects over 40 years from urban and rural sites in Qingdao (Shandong Province, China) were collected. Relative D, M, and F scores per dental region were calculated and compared by paired T-tests. Multivariable logistic regression was used to determine relationships with age, gender, place of residence, and SES.ResultsMean numbers of D and F were low (1.36 respectively 0.27) at all ages. Molars had highest chance for D and M. For the molar region every additional year of age gave significantly lower chance for D and higher chance for M (OR: 0.98 and 1.02 respectively; both p ≤ 0.01). Mean number of M was associated with age (approximately 1.5 in each jaw at 40 years and 6 at 80 years). Females had higher chance for D (OR: 1.34; p ≤ 0.05) and F (OR: 1.69; p ≤ 0.01), and lower chance for M (OR: 0.60; p ≤ 0.01). Urban and rural subjects had similar chance for D; urban subjects had approximately 5 times more chance for F (p ≤ 0.01). SES had no relationship with D and M, however SES low was associated with F (OR: 0.45; p ≤ 0.01). Replacements were significantly associated with age (all dental regions except anterior region), gender (all dental regions), place of residence (whole dentition and molar region), and SES (whole dentition and premolar and molar regions).ConclusionsThe majority of subjects presented a reduced dentition. Molars were most frequently affected by D and M. D, M, F and replaced teeth were associated with the background variables, however differently for different dental regions. Above the age of 70 years, only 64% of the subjects presented not less than 20 natural teeth.

Functional dental status and oral health-related quality of life in an over 40 years old Chinese population

ObjectivesThis study aimed to assess oral health-related quality of life (OHRQoL) related to dental status.Material and methodsOne thousand four hundred sixty-two Chinese subjects over 40xa0years, dentate in both jaws, were categorized in a hierarchical functional classification system with and without tooth replacements. OHIP-14CN scores were used to assess OHRQoL and analyzed using multivariable logistic regression including five dental conditions (‘≥10 teeth in each jaw’; ‘complete anterior regions’; ‘sufficient premolar regions’ (≥3 posterior occluding pairs (POPs)); ‘sufficient molar regions’ (bilaterally ≥1 POP); and tooth replacement) after adjustment for five background variables. Likelihood ratios for impaired OHRQoL (OHIP total score ≥5) were assessed at each level of the classification system.ResultsIn the hierarchical scheme, OHIP-14CN total scores were highest in branch ‘<10 teeth in each jaw’ (8.5u2009±u20099.5 to 12.3u2009±u200913.2). In branch ‘≥10 teeth’ scores ranged from 6.2u2009±u20097.7 to 8.3u2009±u20099.3. The most important dental condition discriminating for impact on OHRQoL was ‘≥10 teeth in each jaw’ (Likelihood ratio 1.59). In this branch subsequent levels were discriminative for impaired OHRQoL (Likelihoods 1.29–1.69), in the branch ‘<10 teeth in each jaw’ they were not (Likelihoods 0.99–1.04). Tooth replacements were perceived poorer as their natural counterparts (odd ratios, 1.30 for fixed and 1.47 for removable appliances).ConclusionsOHRQoL was strongly associated with the presence of at least 10 teeth in each jaw. The hierarchical classification system predicted approximately 60xa0% of subjects correctly with respect to impaired OHRQoL.Clinical relevanceFrom an OHRQoL perspective, natural teeth were preferred over artificial teeth.

Swallowing threshold parameters of subjects with shortened dental arches

OBJECTIVESnTo quantify swallowing threshold parameters of subjects with a moderate shortened dental arch dentition (SDA: missing molar teeth, but premolar teeth in occluding position and uninterrupted anterior regions) compared to subjects with a complete dental arch dentition (CDA).nnnMETHODSnFourteen females with SDA (3-4 occlusal premolar units) and 14 females with CDA were instructed to chew silicone test food (cubic particles with a total volume of 3 cm(3)). They spit it out the moment they felt the urge to swallow and the pulverized particles were collected. Swallowing threshold parameters were number of chewing cycles, time until swallowing, and median particle size of the pulverized particles as determined by sieving the food. Chewing tests were performed twice and outcomes were averaged.nnnRESULTSnThe number of chewing cycles until swallowing of subjects with SDA was approximately 1.7 times (p<0.005) that of the controls and this took approximately 1.6 times more time (p<0.01). The median particle size until swallowing did not differ significantly between the groups, but demonstrated large individual differences. Regression analyses indicated that the ratio of median particle size until swallowing of SDA and CDA becomes progressively unfavourable for SDA with increasing numbers of chewing cycles.nnnCONCLUSIONSnSubjects with SDA pulverized test food particles to sizes comparable to subjects with CDA, but chewed longer with more chewing cycles until swallowing. Higher numbers of chewing cycles were associated with increasing difference between SDA and CDA regarding the median particle size until swallowing.nnnCLINICAL SIGNIFICANCEnCompared to subjects with CDA, subjects with moderate SDA pulverize test food particles to comparable size by chewing longer before swallowing. Therefore, overloading the digestive system by swallowing courser food particles is unlikely in SDA. Consequently, replacement of absent molars just to optimize chewing function is not advised.

Dental functional status with and without tooth replacement in a Chinese adult population

The objective of this study is to investigate the prevalence of missing teeth and prosthodontic replacements in a Chinese adult population using a hierarchical dental functional classification system. A total of 1,462 dentate subjects over 40xa0years from Shandong Province, China were included and categorized in the functional classification system with and without tooth replacements. Depending on replacements, subjects could be reclassified (promoted) to categories reflecting higher functionality. “Promotions” were considered indicators for prosthodontic effectiveness. Homogeneities after dichotomization into functional categories appeared to be moderate to good. In the “≥10 teeth in each jaw” branch, mean number of teeth and posterior occluding pairs were 27.93u2009±u20092.74 and 7.10u2009±u20091.94, respectively. In the branch “<10 teeth in each jaw,” these figures were 16.17u2009±u20095.54 and 1.49u2009±u20091.45. Fixed dental prostheses (FDPs) added on average 3.5 artificial teeth; 46% of subjects with FDP promoted to a higher functional level. For removable dental prostheses (RDPs), these numbers were 8.5% and 79%, respectively. Promotion value per tooth added was significantly higher for FDPs. The classification system was able to quantify the effectiveness of teeth replacements. It was shown that RDPs were more effective when higher numbers of teeth were replaced, while FDPs were more effective per artificial tooth added.