A comparative study of the Osstell™ versus the Osstell Mentor™ to evaluate implant stability in human cadaver mandibles

The aim of this study was to assess the primary stability of dental implants by resonance frequency analysis (RFA) using the Osstell? and Osstell Mentor? devices and to investigate the reproducibility and comparability of the results obtained with these devices. Twenty‐four Straumann implants (Straumann AG, Basel, Switzerland) were placed in the anterior mandible of 12 fresh edentulous human cadaver mandibles. The implant stability quotients (ISQs) were measured with the Osstell? and Osstell Mentor? when implants were inserted at 50% of their length and following their complete insertion. The Osstell? device measured lower scores compared with the Osstell Mentor?. This was significant for the full position (mean difference = 9·9), t (11) = 7·4, P < 0·001 and for the halfway position (mean difference = 5·9), t (11) = 2·41, P = 0·03. In con‐clusion, the Osstell? produced relatively lower ISQ scores than the Osstell Mentor?.     

Effect of prosthetic restoration on oral health‐related quality of life in patients with shortened dental arches: a multicentre study

The aim of this multicentre prospective study was to investigate the effect of prosthetic restoration for missing posterior teeth in patients with shortened dental arches (SDAs). SDA patients with 2–12 missing occlusal units (a pair of occluding premolars corresponds to one unit, and a pair of occluding molars corresponds to two units) were consecutively recruited from seven university‐based dental hospitals in Japan. Patients chose no replacement of missing teeth or prosthetic treatment with removable partial dentures (RPDs) or implant‐supported fixed partial dentures (IFPDs). Oral health‐related quality of life (OHRQoL) was measured using the oral health impact profile (Japanese version – OHIP‐J) at baseline and follow‐up/post‐treatment evaluation. Of the 169 subjects who completed baseline evaluation, 125 subjects (mean age; 63·0 years) received follow‐up/post‐treatment evaluation. No‐treatment was chosen by 42% (53/125) of the subjects, and 58% (72/125) chose treatment with a RPD (n = 53) or an IFPD (n = 19). In the no‐treatment (NT) group, the mean OHIP summary score at baseline was similar to that at follow‐up evaluation (P = 0·69). In the treatment (TRT) group, the mean OHIP summary score decreased significantly after the RPD treatment (P = 0·002), and it tended to decrease, though not statistically significant (P = 0·18), after the IFPD treatment. The restoration of one occlusal unit was associated with a 1·2‐point decrease in OHIP summary score (P = 0·034). These results suggest that the replacement of missing posterior teeth with RPDs or IFPDs improved OHRQoL. Prosthetic restoration for SDAs may benefit OHRQoL in patients needing replacement of missing posterior teeth.     

Association between occlusal force distribution in implant overdenture prostheses and residual ridge resorption

This study aimed to investigate residual ridge resorption (RRR) of anterior and posterior maxillary and mandibular edentulous ridges, in patients treated with mandibular implant overdentures (IOD) and compare with conventional complete denture (CD) wearers, and to determine at each location, the association of RRR with the occlusal forces distribution and other patients’ variables. The anterior and posterior RRR of IOD (six males, 17 females) and CD (12 males, 11 females) groups were determined using baseline and follow‐up dental panaromic radiographs (DPT) (mean intervals 4 ± 1·8 years). The bone ratios were calculated using proportional area: anatomic to fixed reference areas and mean difference of ratios between the intervals determined RRR. The ridge locations included anterior and posterior maxillary and posterior mandibular arches. The T‐Scan III digital occlusal system was used to record anterior and posterior percentage occlusal force (%OF) distributions. There were significant differences in anterior and posterior %OF between treatment groups. Two‐way anova showed RRR was significant for arch locations (P = 0·005), treatment group (IOD versus CD) (P = 0·001), however, no significant interaction (P = 0·799). Multivariate regression analyses showed significant association between RRR and %OF at anterior maxilla (P = 0·000) and posterior mandible (P = 0·023) and for treatment groups at posterior maxilla (P = 0·033) and mandibular areas (P = 0·021). Resorption was observed in IOD compared to CD groups, with 8·5% chance of less resorption in former and 7·8% in the latter location. Depending on arch location, ridge resorption at various locations was associated with occlusal force distribution and/or treatment groups (implant prostheses or conventional complete dentures).     

Swallowing threshold parameters of subjects with shortened dental arches

Objectives

To 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).

Methods

Fourteen 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 cm³). 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.

Results

The 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.

Conclusions

Subjects 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’.

Clinical significance

Compared 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.     

Increased risk for premolar tooth loss in shortened dental arches

ObjectivesTo assess sustainability of shortened dental arches (SDA) by determining time to ‘first restorative intervention’ of teeth and time to ‘tooth loss’ and comparing these outcomes with complete dental arches (CDA) and SDA plus removable dental prostheses (RDP).MethodsData (follow-up time ranged from 27.4 (SD 7.1) to 35.0 (SD 5.6) years; max. follow up: 45.8 years) from patient records of 59 subjects (23 SDA, 23 CDA, and 13 SDA plus RDP) participating in a prospective cohort study on shortened dental arches (SDA) were analysed. Group effects on survival were analysed using Cox regression models; where appropriate Kaplan–Meier analyses were done.ResultsCompared to SDA subjects, CDA subjects had a lower risk to receive a first restorative intervention in anterior teeth (HR = 0.377; 95% CI [0.205–0.695]) and premolars (HR = 0.470; 95% CI [0.226–0.977]). CDA subjects had a lower risk to lose premolars compared to SDA subjects (HR = 0.130; 95% CI [0.053–0.319]). Risk for ‘first restorative intervention’ and for ‘tooth loss’ did not significantly differ between SDA with and without RDP.ConclusionsSDA subjects had an increased risk to lose premolars and to receive a first time restoration in anterior teeth and premolars compared to CDA subjects. SDA subjects with RDP had no increased risk to receive a first restorative intervention or for tooth loss compared to SDA without RDP.Clinical relevanceSubjects with shortened dental arches can be discerned as enduring at-risk patients. It is therefore recommended that shortened dental arch subjects receive intensive and continuous care to prevent further tooth loss.     

Oral health and caries related microflora in children during the first three months following renal transplantation

There is little information on the oral health of children undergoing renal transplantation during the early transplant period. Methods. Twenty‐four children undergoing renal transplantation aged 4–13·2 years and their matched controls were recruited. The dmfs, dmft, DMFS and DMFT, plaque, gingivitis and gingival enlargement scores were recorded. The oral microflora was sampled and cultured for S. mutans, Lactobacllus species and Candida species. Results. There was a significantly lower mean dmfs (0·3 ± 0·9; P = 0·03), dmft (0·3 ± 0·9; P = 0·03), DMFS (2·3 ± 5·3; P = 0·01) and DMFT (1·5 ± 2·6; P = 0·02), respectively, in the transplant group. There was a significantly greater mean plaque score (14·7 ± 11) for the permanent dentition, at baseline only, compared with 90 days post‐transplantation (9·4 ± 10·4; P = 0·02). There was a significantly greater gingival enlargement score (1·8 ± 1·4; P = 0·04) 90 days post‐transplantation compared with baseline. The S. mutans and Lactobacillus counts were significantly lower both at baseline (P = 0·0001 and P = 0·004) and 90 days post‐transplantation (P = 0·02; and P = 0·05), respectively, compared with the controls. Conclusions. The transplant children had less active dental disease than the controls although gingival enlargement needs careful monitoring.     

Turned versus anodised dental implants: a meta‐analysis

The aim of this meta‐analysis was to test the null hypothesis of no difference in the implant failure rates, marginal bone loss (MBL)and post‐operative infection for patients being rehabilitated by turned versus anodised‐surface implants, against the alternative hypothesis of a difference. An electronic search without time or language restrictions was undertaken in November 2015. Eligibility criteria included clinical human studies, either randomised or not. Thirty‐eight publications were included. The results suggest a risk ratio of 2·82 (95% CI 1·95–4·06, P < 0·00001) for failure of turned implants, when compared to anodised‐surface implants. Sensitivity analyses showed similar results when only the studies inserting implants in maxillae or mandibles were pooled. There were no statistically significant effects of turned implants on the MBL (mean difference‐MD 0·02, 95%CI ?0·16–0·20; P = 0·82) in comparison to anodised implants. The results of a meta‐regression considering the follow‐up period as a covariate suggested an increase of the MD with the increase in the follow‐up time (MD increase 0·012 mm year^?1), however, without a statistical significance (P = 0·813). Due to lack of satisfactory information, meta‐analysis for the outcome ‘post‐operative infection’ was not performed. The results have to be interpreted with caution due to the presence of several confounding factors in the included studies.     

Transcranial direct current stimulation and exercises for treatment of chronic temporomandibular disorders: a blind randomised‐controlled trial

To evaluate the effect of adding transcranial direct current stimulation (tDCS) to exercises for chronic pain, dysfunction and quality of life in subjects with temporomandibular disorders (TMD). Participants were selected based on the RDC/TMD criteria and assessed for pain intensity, pressure pain threshold over temporomandibular joint and cervical muscles and quality of life. After initial assessment, all individuals underwent a 4‐week protocol of exercises and manual therapy, together with active or sham primary motor cortex tDCS. Stimulation was delivered through sponge electrodes, with 2 mA amplitude, for 20 min daily, over the first 5 days of the trial. A total of 32 subjects (mean age 24·7 ± 6·8 years) participated in the evaluations and treatment protocol. Mean pain intensity pre‐treatment was 5·5 ± 1·4 for active tDCS group, and 6·3 ± 1·2 for sham tDCS. Both groups showed a decrease in pain intensity scores during the trial period (time factor – F_4·5,137·5 = 28·7, P < 0·001; group factor – F_1·0,30·0 = 7·7, P < 0·05). However, there were no differences between the groups regarding change in pain intensity (time*group interaction – F_4·5,137·5 = 1·5, P = 0·137). This result remained the same after 5 months (t‐test t = 0·29, P > 0·05). Pressure pain thresholds decrease and improvement in quality of life were also noticeable in both groups, but again without significant differences between them. Absolute benefit increase was 37·5% (CI 95%: ?15·9% to 90·9%), and number needed to treat was 2·66. This study suggests that there is no additional benefit in adding tDCS to exercises for the treatment of chronic TMD in young adults.     

Effect of length post and remaining root tissue on fracture resistance of fibre posts relined with resin composite

To investigate the influence of post length and amount of remaining root tissue on the fracture resistance of roots restored with fibre posts relined with resin composite. Ninety upper canine teeth were divided into nine groups (n = 10). The post spaces were prepared resulting in different lengths, as follows: group 2/3, preparations with lengths of 10 mm; group 1/2, preparations with lengths of 7·5 mm; and group 1/3, preparations with lengths of 5 mm. Each group was divided into 3 subgroups according to amount of remaining root tooth tissue (2, 1 mm or 0·5 mm of thick root). Fibre posts relined with resin composite were cemented, and all teeth were restored with metal crowns. The samples were submitted to the fracture resistance test in a universal testing machine, at an angle of 135° and speed of 0·5 mm min^?1. Failure modes were observed and the data of fracture resistance were submitted to the anova and Tukey's (α = 0·05). No statistically significant difference in fracture resistance was found among different post lengths (P > 0·05). Remaining dentin thickness of 2 and 1 mm did not differ statistically in fracture resistance (P > 0·05), which was higher than of 0·5 mm dentin thickness (P < 0·05). A prevalence of repairable failure was observed in all groups. It can be concluded that the length of fibre post relined with resin composite did not influence fracture resistance, but thickness was an important factor for the restoration of endodontically treated teeth.     

Dental trauma among 5th and 6th grade Arab schoolchildren in Eastern Jerusalem

Abstract –  Dental trauma is an irreversible pathology which after occurrence is characterized by life long debilitating effects. The objective of the study was to measure the prevalence of trauma in anterior permanent teeth among children and associations with independent variables. A total of 453 5th and 6th grade Arab Eastern Jerusalem schoolchildren participated. Trauma, incisal overjet and lip competence were measured by one examiner in the schools. Reasons and location of trauma were assessed by telephone interviews with the parents. The total prevalence of dental trauma was 33.8%. Severe trauma prevalence (involving dentine) was 12.6%. Severe trauma was more prevalent among boys (OR = 2.03, P  = 0.026); children with lip incompetence (OR = 2.71, P  = 0.001); and those with an overjet of 4mm or more (OR = 3.73, P  < 0.001). The main reported causes for dental trauma were falling (29.1%), sports (16.4%), violence (20%) and playing (20%). According to the parents' reports, more fall-related injuries were reported at home, more sport injuries at school, more 'playing' injuries 'outside' ( P  < 0.001). Combination of results with a previous study among Jewish schoolchildren demonstrated: severe dental trauma was related to overjet (OR = 1.73, P  = 0.002), lip incompetence (OR = 2.19, P  < 0.001), gender (OR for males = 1.54, P  = 0.005), but not to ethnicity (Arab or Jewish). The reasons for trauma observed in this study were potentially preventable. A community effort should therefore be pursued, with the aim of educating sports teachers, teachers, health personnel and schoolchildren regarding awareness of dental trauma prevention, with emphasis on utilizing mouthguards and early orthodontic intervention, when financially possible.     

Effect of prosthetic restoration on masticatory function in patients with shortened dental arches: a multicentre study

The aim of this multicentre study was to investigate the effect of prosthetic restoration for missing posterior teeth on mastication in patients with shortened dental arches (SDAs). Partially dentate patients who had an intact teeth in anterior region and missed distal molar(s) (2–12 missing occlusal units) classified as Kennedy Class I or Class II were recruited from seven university‐based dental hospitals in Japan. Of the 125 subjects who underwent baseline (pre‐treatment) and follow‐up/post‐treatment evaluation, 53 chose no replacement of missing teeth and 72 chose treatment with removable partial dentures (n = 53) or implant‐supported fixed partial dentures (n = 19). Objective masticatory performance (MP) was evaluated using a gummy jelly test. Perception of chewing ability (CA) was rated using a food intake questionnaire. In the no‐treatment group, mean MP and CA scores at baseline were similar to those at follow‐up evaluation (P > 0·05). In the treatment group, mean MP after treatment was significantly greater than the pre‐treatment mean MP (P < 0·05). However, the mean perceived CA in the treatment groups was similar at pre‐ and post‐treatment (P > 0·05). In a subgroup analysis of subjects in the treatment group, subjects with lower pre‐treatment CA showed a significant CA increase after treatment (P = 0·004), but those with higher pre‐treatment CA showed a significant decrease in CA (P = 0·001). These results suggest that prosthetic restoration for SDAs may benefit objective masticatory performance in patients needing replacement of missing posterior teeth, but the benefit in subjective chewing ability seems to be limited in subjects with perceived impairment in chewing ability before treatment.     

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 (Spearman's 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.     

Comparison of utility weighted DMFT with patient‐reported oral well‐being

This study investigated a method of measuring oral health, as opposed to measuring disease. The objective was to compare DMF score and whole mouth utility scores to a patient‐reported outcome measure (PROM). Disutility values for lost and restored teeth were used to weight the decayed, missing and filled teeths(DMFTs) of 10 adult patients. This gave two whole mouth utility scores (WMU). These scores were then compared with a patient‐reported oral health outcome measure recorded by the use of a visual analogue scale (VAS). The anchors for the VAS were ‘my mouth could not be worse’ and ‘my mouth could not be better’. There was a positive correlation (r = 0·6457) between WMU1 and the patient‐reported outcome measure (P < 0·05) and a negative correlation (r = ?0·8383) between WMU1 and DMFT which was significant at the P < 0·01 level. There was a statistically significant positive correlation of r = 0·7926 between WMU2 and the patient‐reported outcome measure (P < 0·01) and a negative correlation (r = ?0·9393) between WMU2 and DMFT (P < 0·01). The Pearson's correlation between DMFT and the patient‐reported outcome measure was ?0·8757, which was significant at the 0·01 level. Patient reports of their perceived level of health correlate well with DMFT scores. Weighting DMFT scores according to the differential values assigned to missing, or missing and filled, teeth does not increase the degree of correlation between the measure and the patients’ personal quantification of their oral health. Decayed, missing and filled teeth therefore seems to adequately capture the patient's sense of well‐being.     

Impact of shortened dental arches on oral health‐related quality of life

This study described the prevalence of adults with shortened dental arches (SDA) in Brazil, specifically assessing the differences of oral health‐related quality of life [the prevalence and severity of oral impacts on daily performance (OIDP)] by dentition status. We analysed data from the 2010 National Survey of Oral Health in Brazil, including home interviews and oral examinations. The assessment of SDA used two alternative definitions: having 3–5 natural occlusal units (OUs) in posterior teeth or having 4 OUs in posterior teeth. Both definitions included having intact anterior region and no dental prosthesis. The analysis was weighted, and a complex sampling design was used. Negative binomial regression models assessed associations as adjusted for socio‐demographic conditions and dental outcomes. A total of 9779 adults (35–44 years old) participated in the study. A non‐negligible proportion had SDA: 9·9% and 3·8% for the first and second definition, respectively. Individuals with SDA (first definition) ranked higher in OIDP prevalence [count ratio (CR) 1·22; 1·09–1·36, 95% confidence interval (CI)] and severity (CR = 1·43; 1·19–1·72, 95% CI) than those with more natural teeth. This difference was not statistically significant when adjusted for socio‐demographic and dental covariates: OIDP prevalence (CR = 1·04; 0·92–1·17, 95% CI) and severity (CR = 1·09; 0·91–1·30, 95% CI). Analogous results were obtained when the second definition of SDA was adopted. These findings suggest that a considerable contingent of adults may function well without dental prostheses, despite having several missing teeth. This conclusion challenges the traditional approach of replacing any missing tooth and instructs the allocation of more dental resources to preventive, diagnostic and restorative services.     

A reliability study of clinical occlusal tooth wear measurements

Tooth wear represents a clinical problem that is becoming increasingly important in ageing populations. Attrition caused by bruxism is its most visible sign. To determine the optimal moment to start the restoration of the worn dentition, one should first be able to measure the amount of tooth wear reliably in the clinical setting. So far, most studies of tooth wear severity have been performed on dental study casts. However, such an indirect approach is less applicable to the everyday dental practice, the more so because by grading of casts, the identification of dentine exposure is hard or even impossible to achieve. In this study, occlusal tooth wear was assessed clinically in 45 volunteers (17 men; 28 women; mean age 33·7 ± 10·7 years), TMD patients and symptom‐free persons alike, on four occasions: two calibrated examiners graded the occlusal wear at two different points in time, using a 5‐point scale (0=no wear; 1=visible wear within the enamel; 2=visible wear with dentine exposure and loss of clinical crown height <1/3; 3=loss of crown height between 1/3 and 2/3; 4=loss of crown height >2/3). The overall values of the intra‐rater and interrater reliability, expressed as Cohen's κ, were substantial (κ=0·632–0·678) and did not differ significantly from one another (repeated measures anova : F_3,19=1·428, P=0·266). The clinical variable ‘quadrant’ (e.g. right maxillary dental arch) did not influence the values of κ whereas the interrater reliability during the first session was better for the element types ‘incisors’ and ‘cuspids’ than for the element type ‘premolars’ (one‐way anova : F_3,23=4·577, P=0·012; post hoc Bonferroni tests: P=0·030 and 0·036). Qualitative assessment of the clinical variable ‘severity of wear’ indicated that the more advanced the tooth wear is, the more reliably it can be graded. The presence of restorations did not influence the reliability. It was concluded that occlusal tooth wear can be assessed reliably in the clinical setting, especially in the anterior parts of a dentition that demonstrates considerable wear. (Supported by the lOT)     

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

Objectives

The 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 methods

Data (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).

Results

Records of 35 % of the original cohort were retrievable. At the end of the follow-up (27.4?±?7.1 years), 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 32.6?±?7.3 years). Sixteen out of 23 CDA subjects still had CDA; none of them lost more than one POP (follow-up 35.0?±?5.6 years). 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.

Conclusion

Shortened dental arches can last for 27 years and over. Clinical course in SDA plus RDP is unfavourable, especially when RDP-related interventions are taken into account.

Clinical relevance

The 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.     

Management of shortened dental arches and periodontal health: 5‐year results of a randomised trial

In a multicentre randomised trial (German Research Association, grants DFG WA 831/2‐1 to 2‐6, WO 677/2‐1.1 to 2‐2.1.; controlled‐trials.com ISRCTN97265367), patients with complete molar loss in one jaw received either a partial removable dental prosthesis (PRDP) with precision attachments or treatment according to the SDA concept aiming at pre‐molar occlusion. The objective of this current analysis was to evaluate the influence of different treatments on periodontal health. Linear mixed regression models were fitted to quantify the differences between the treatment groups. The assessment at 5 years encompassed 59 patients (PRDP group) and 46 patients (SDA group). For the distal measuring sites of the posterior‐most teeth of the study jaw, significant differences were found for the plaque index according to Silness and Löe, vertical clinical attachment loss (CAL‐V), probing pocket depth (PPD) and bleeding on probing. These differences were small and showed a slightly more unfavourable course in the PRDP group. With CAL‐V and PPD, significant differences were also found for the study jaw as a whole. For CAL‐V, the estimated group differences over 5 years amounted to 0·27 mm (95% CI 0·05; 0·48; P = 0·016) for the study jaw and 0·25 mm (95% CI 0·05; 0·45; P = 0·014) for the distal sites of the posterior‐most teeth. The respective values for PPD were 0·22 mm (95% CI 0·03; 0·41; P = 0·023) and 0·32 mm (95% CI 0·13; 0·5; P = 0·001). It can be concluded that even in a well‐maintained patient group statistically significant although minor detrimental effects of PRDPs on periodontal health are measurable.     

Patterns of missing occlusal units and oral health-related quality of life in SDA patients

Summary  The aim of this study was to explore the relationship between patterns of missing occlusal units (OUs) and oral health-related quality of life (OHRQoL) in subjects with the shortened dental arches (SDAs). Subjects with SDAs were recruited consecutively for 1 month from six university-based prosthodontic clinics. In total, 115 SDA subjects participated (mean age, 58·5 ± 10·0 years; 71% female). The location and number of missing teeth were examined and the number of missing OUs was calculated. To evaluate OHRQoL, the Japanese version of the Oral Health Impact Profile (OHIP-J) was administered and the summary score of OHIP-J was calculated. The SDA subjects were categorized depending upon the anterior-posterior lengths of the missing or remaining OUs. Regression analyses were performed to investigate the OHIP-J differences between groups of subjects with various anterior–posterior SDA lengths. The analyses revealed that subjects who only lost the second molar contact exhibited significantly better OHRQoL than those who lost more teeth [coefficient: 11·1, 95% confidence interval (CI): 2·8–19·2, P  = 0·02]. Furthermore a statistically significant group difference was observed between the groups with and without the first molar occlusal contact (coefficient: 12·8, 95% CI: 1·4 to 24·1, P  = 0·03). In conclusion, although our results are of exploratory nature and need validation, patterns of missing OUs are likely to be related to the OHRQoL impairment in SDA subjects with the presence of first molar contact having a particularly important role.     

Effects of oral care with tongue cleaning on coughing ability in geriatric care facilities: a randomised controlled trial

Methods for preventing aspiration pneumonia are needed soon in order to reduce mortality from aspiration pneumonia and promote the health of the elderly. The aim of this randomised controlled trial was to examine whether oral care with tongue cleaning improves coughing ability in elderly individuals living in geriatric care facilities. Participants comprised of 114 residents of 11 group homes and private nursing homes in Aso City in Kumamoto Prefecture. Participants were randomly assigned to either (i) a group that underwent routine oral care with tongue cleaning (intervention group; n = 58) or (ii) a group that underwent routine oral care alone (control group; n = 56). Coughing ability was evaluated by measuring peak expiratory flow (PEF) before and after 4 weeks of intervention. Before the intervention, PEF did not differ significantly between the intervention group (1·65 ± 1·11 L s^?1) and control group (1·59 ± 1·05 L s^?1; P = 0·658). However, on termination of the intervention, PEF was significantly higher in the intervention group (2·54 ± 1·42 L s^?1) than in the control group (1·90 ± 1·20 L s^?1; P = 0·014). After the intervention, PEF had increased significantly in both groups; however, this increase was significantly greater in the intervention group (0·90 ± 0·95 L s^?1) than in the control group (0·31 ± 0·99 L s^?1; P < 0·001). Oral care with tongue cleaning led to increased PEF, suggesting improved coughing ability. Oral care incorporating tongue cleaning appears to be important for preventing aspiration pneumonia.     

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.