DO ORAL CARE AND REHABILITATION IMPROVE COGNITIVE FUNCTION? A SYSTEMATIC REVIEW OF CLINICAL STUDIES.

OBJECTIVES: An increasing number of studies have identified an association between oral health status and cognitive function. However, the effect of oral interventions, including oral health care, dental treatment and oral motor exercises, on cognitive function remains unclear. This systematic review examined whether oral interventions contribute to the long-term improvement of cognitive status. METHODS: Four databases were searched (MEDLINE, Web of Science, Cochrane Library, and ICHUSHI Web) to identify randomized and nonrandomized controlled trial studies and prospective cohort studies from inception until 1 September 2023, published in English or Japanese. The Cochrane risk of bias tool for randomized controlled trials and the risk of bias assessment tool for nonrandomized studies were used to assess bias risk. RESULTS: A total of 20 articles were included in the qualitative analysis; 13 articles were published in English, and 7 were published in Japanese. The implemented interventions were oral care in 8 studies, dental treatment in 8 studies, and oral motor exercise in 4 studies. One study found a significant effect on attention following oral care intervention. Some dental treatments influenced cognitive function, although a clear positive effect was not determined. In 1 study, attention and working memory improved in the chewing exercise group. CONCLUSIONS: Several studies verified the improvement effects of oral interventions, such as oral care, dental treatment, and oral motor exercise, on cognitive function or impairment. However, there was still a lack of conclusive evidence that such an intervention clearly improved cognitive function. To clarify the effects of oral interventions on cognitive function, it is necessary to examine participants, interventions, and outcome measures in detail.

Prosthodontic treatment can improve the ingestible food profile in Japanese adult outpatients.

PURPOSE: To investigate the effect of prosthodontic treatment on the ingestible food profile in adult Japanese outpatients, and to identify the related risk factors that can deteriorate the profile. METHODS: The participants were 277 outpatients who visited university-based specialty clinics in Japan for prosthodontic treatment. The demographic data, number of present teeth assessed via intraoral examination, and oral health-related quality of life assessed by the total Oral Health Impact Profile (OHIP-J54) scores of all participants were recorded before treatment. Ingestible food profile score (IFS) was recorded using a validated food intake questionnaire. Eligible participants who answered the questionnaire before and after treatment were categorized into five groups based on the prosthodontic treatments they received (i.e., crowns, bridges, removable partial dentures, removable complete dentures, and removable complete and partial dentures). RESULTS: Multivariate analysis of covariance revealed a statistically significant main effect of prosthodontic intervention (time course: before and after treatment) on mean IFS (P=0.035, F=4.526), even after adjusting for covariates (age, number of present teeth, and treatment modality). Multiple linear regression analysis revealed that the low number of present teeth (r=0.427, P<0.001) and a high OHIP-J54 total score (r=-0.519, P<0.001) of the patients at the baseline were significantly associated with their baseline IFSs, even after adjusting for confounding variables. CONCLUSIONS: The findings of this multicenter follow-up study indicate the importance of prosthodontic rehabilitation in improving patients' ingestible food profiles.

Mandibular residual ridge shape and the masticatory ability in complete denture wearers.

PURPOSE: The purpose of this study was to investigate the influence of mandibular residual ridge shape on the masticatory ability in complete denture wearers. METHODS: The subject group consisted of 199 complete denture wearers. The mandibular residual ridge of each subject was evaluated using a replica of the ridge which was obtained with heavy-body silicone impression material. The basal area of each replica was measured with a digitizer. The volume and the height of each replica were also calculated. The masticatory ability of each subject was evaluated using a-25-item food intake questionnaire method by authors. The masticatory score of each subject was calculated to represent the masticatory ability. Furthermore, all subjects were divided into three groups (S, M, L group) according to the value of the basal area. RESULTS: There were statistically significant correlations between the basal area of the residual ridge and the masticatory score (r = 0.366, p < 0.01), and also the volume of the residual ridge and the masticatory score (r = 0.314, p < 0.01). The basal area of the residual ridge, the volume of the residual ridge, and the masticatory score of the L group (29 persons) were statistically larger than those of the M group (136 persons) and the S group (34 persons) (p < 0.05), and those values in the M group were statistically larger than those of the S group (p < 0.05). CONCLUSION: It was confirmed that the basal area of denture foundation of the mandible had an influence on the masticatory ability in complete denture wearers.

A multi-centered epidemiological study evaluating the validity of the treatment difficulty indices developed by the Japan Prosthodontic Society.

PURPOSE: The Japan Prosthodontic Society developed a multi-axis assessment protocol to evaluate the complex variations in patients who need prosthodontic care, and to classify the level of treatment difficulty. A previous report found the protocol to be sufficiently reliable. The purpose of this multi-center cohort study was to evaluate the validity of this multi-axis assessment protocol. METHODS: The treatment difficulty was evaluated using the multi-axis assessment protocol before starting prosthodontic treatment. The time required for active prosthodontic treatment, medical resources such as treatment cost, and changes in the oral health-related QOL before and after treatment, were evaluated after treatment completion. The construct validity of this protocol was assessed by the correlation between the dentist's pre-operative subjective assessment of the treatment difficulty, and the level of difficulty determined by this protocol. The predictive validity was assessed estimating the correlations between a "comprehensive level of treatment difficulty" based on the four axes of this protocol and total treatment cost, total treatment time, and changes in the oral health-related QOL before and after treatment. RESULTS: The construct validity of this protocol was well documented except for psychological assessment. Regarding the predictive validity, the comprehensive level of treatment difficulty assessed before treatment was significantly correlated with the three surrogate endpoints known to be related to the treatment difficulty (total treatment cost, treatment time, and improvement in the oral health-related QOL). To further clarify the validity of the protocol according to patients' oral condition, a subgroup analysis by defects was performed. Analyses revealed that treatment difficulty assessment before treatment was significantly related to one or two surrogate endpoints in the fully edentulous patients and the partially edentulous patients. No significant relationship was observed in the patients with mixture of full/partial edentulism and the patients with teeth problems, possibly due to the small sample size in these groups. CONCLUSION: This study revealed that the multi-axis assessment protocol was sufficiently valid to predict the level of treatment difficulty in prosthodontic care in patients with fully edentulous defects and with partially edentulous defects.

[Construction and promotion of prosthodontics based on health sciences: for the achievement of a long life and good health cultivated by occlusion and mastication].

Prosthodontics is a practical science based on life sciences and health sciences, and takes a role to contribute to the improvement of people's health and welfare. It is true the main field of prosthodontics and/or prosthodontic treatments is oral rehabilitation including recoveries of morphological defects and the functional disability caused by teeth loss. From this point of view, I am sure that the ultimate target of prosthodontics and/or prosthodontic treatments is maintenance and improvement of patient's QOL. To achieve this purpose, I think research, education, and clinical practice to be inseparable and integral in prosthodontics. This ensures that prosthodontics become more academic which can contribute to the society more greatly. Advertisement disclosure of "Prosthodontic Specialist certified by Japan Prosthodontic Society" is our earnest wish. The specialist system is regarded to be effective for the improvement of the medical treatment level, the information provision to the patient, and the promotion of cooperation hospital and clinic. On the other hand, the high quality treatments are severely requested and the specialists are strictly evaluated by the many people more than before. We have to be aware of our responsibility as Prosthodontic Specialists. In addition, Japan Prosthodontic Society is a corporate judicial person, and there is obligation and a responsibility that transmit necessary information to the society certainly and promptly, and present various proposals based on EBM as the opinion leader. Concretely, it is necessary to promote basic researches as well as clinical researches on prosthodontic treatments, and to examine the improvement of educational methods of prosthodontics. Let's reconfirm the purpose of our Society written in the article of incorporation and make an effort to achieve this purpose!

Reliability and validity of the patient disability-oriented diagnostic nomenclature system for prosthetic dentistry.

PURPOSE: The Japan Prosthodontic Society (JPS) has proposed a new diagnostic nomenclature system (DNS), based on pathogenesis and etiology, to facilitate and improve prosthodontic treatment. This system specifies patient disability and the causative factor (i.e. "B (disability) caused by A (causative factor)"). The purpose of this study was to examine the reliability and validity of this DNS. STUDY SELECTION: The JPS Clinical Guideline Committee assessed mock patient charts and formulated disease names using the new DNS. Fifty validators, comprising prosthodontic specialists and dental residents, made diagnoses using the same patient charts. Reliability was evaluated as the consistency of the disease names among the validators, and validity was evaluated using the concordance rate of the disease names with the reference disease names. RESULTS: Krippendorff's α was 0.378 among all validators, 0.370 among prosthodontic specialists, and 0.401 among dental hospital residents. Krippendorff's α for 10 validators (3 specialists and 7 residents) with higher concordance rates was 0.524. Two validators (1 specialist and 1 resident) with the highest concordance rates had a Krippendorff's α of 0.648. Common disease names had higher concordance rates, while uncommon disease names showed lower concordance rates. These rates did not show correlation with clinical experience of the validator or time taken to devise the disease name. CONCLUSIONS: High reliability was not found among all validators; however, validators with higher concordance rates showed better reliability. Furthermore, common disease names had higher concordance rates. These findings indicate that the new DNS for prosthodontic dentistry exhibits clinically acceptable reliability and validity.

[Expectations for prosthetic dentistry as a health science].

Prosthodontics is a practical science based on life sciences and health sciences, and takes a role to contribute to improvement of health/welfare of peoples. By prosthodontic researches including life sciences and health science, it will be proved that the practice of prosthetic dental treatments is important to health/welfare. In addition, our research activities are expected because of the demographic change caused by the increase of aging population. The scientific research activity of our society is one of the activities for main medical/dental care demanded definitely in the 21st century. Especially, promotion of brain research is just going to be expected. From a prosthodontic treatment point of view, the improvement of diagnostic study focusing on the examining method and the inspecting method is desired. It is included in a diagnosis to predict a degree of functional recovery after prosthodontic treatments. For the evaluation of masticatory function, the evaluating method for the organ and tissue constituting stomatognathic system is necessary as well as the evaluating method for masticatory function. It is hoped that efforts will be made to establish evaluating methods for each organ and tissue in stomatognathic system will be made. As a corporate judicial person, we must build up public-interest activities. It is necessary to provide sufficient information to all dentists in order to offer a quality prosthodontic care by improvement of diagnostic and treatment abilities. Moreover, it is necessary to practice active enlightenment activity about clinical significance of prosthodontic treatment, and to develop strategies to make peoples recognize "prosthodontics as a health science" widely.

Retrospective comparison of open versus laparoscopic ventral and incisional hernia repair.

INTRODUCTION: We performed a retrospective study to determine the mid-term recurrence and complication rates of patients following laparoscopic ventral and incisional hernia repair (LVHR) with DualMesh, an expanded polytetrafluoroethylene (ePTFE) mesh. Additionally, a study of the mesh contraction rate was performed postoperatively. METHODS: We compared open mesh repair of ventral and incisional hernias (OR) and LVHR. We also analyzed the shrinkage rate of ePTFE mesh. We included 45 patients (21 OR, 24 LVHR) who underwent mesh repair for primary ventral and incisional hernias between January 2008 and December 2012. Patients' characteristics did not significantly differ between the two groups. RESULTS: Mean operating time was 152.7 min for the OR group and 143.1 min for the LVHR group (P = 0.25). Mean postoperative hospital stay was 13.4 days for the OR group and 6.8 days for the LVHR groups (P = 0.01). The postoperative complication rate was 28.6% for the OR group and 12.5% for the LVHR group (P = 0.03). Among OR patients, causes of morbidity were variable: two recurrent cases, one surgical-site infection, one re-recurrence, one case of enteritis, and one case of heart failure. Among the LVHR patients, there was one surgical-site infection and two cases of seroma. No patients in the LVHR group experienced recurrence, while 14.3% of OR patients had a recurrence. In the LVHR group, the mean ePTFE mesh contraction rate was 10.6%. CONCLUSION: LVHR has advantages compared with OR, and the post-insertion contraction rate of ePTFE mesh was 10.6%.

A multi-centered epidemiological study evaluating the reliability of the treatment difficulty indices developed by the Japan Prosthodontic Society.

BACKGROUND: The diagnostic assessment of the level of difficulty in treating patients who need prosthodontic care is useful to establish a medico-economically efficient system with primary care dentists and prosthodontic specialists. MATERIALS AND METHODS: A multi-axis assessment protocol was established using the newly established treatment difficulty indices. The protocol contains Axis I: oral physiological conditions (e.g., teeth damage and/or missing teeth); Axis II: general health and sociological conditions (e.g., medical disorders); Axis III: oral health-related quality of life (OHRQOL; e.g., oral health impact profile: OHIP); and Axis IV: psychological health (e.g., mood, anxiety, somatoform disorders). A preliminary study on the test-retest consistency of the protocol was conducted to check the levels of reliability of the indices prior to a large-scale, multi-center cohort study on the validity of the protocol. RESULTS: The test-retest consistency in terms of the oral physiological condition (Axis I) after data reduction was 0.82 [corrected] for patients with teeth problems, 0.73 [corrected] for partially edentulous patients, and 0.78 [corrected] for edentulous patients. The reliability for general health and sociological conditions (Axis II), OHRQOL (Axis III), and psychological health (Axis IV) were 0.88, 0.74, and 0.61, respectively. These values reflect either "sufficient agreement" or "excellent agreement" in accordance with the criteria established by Landis and Koch (1977) [1]. CONCLUSION: This protocol is the first multi-axis assessment scheme introduced for prosthodontic treatment with sufficient reliability. This new system is therefore expected to have a significant impact on future dental diagnostic nomenclature systems.

Effect of wearing a palatal plate on swallowing function.

PURPOSE: The purpose of this study was to determine the effect of wearing a palatal plate on swallowing function. METHODS: The subject group consisted of 10 healthy, fully dentate males. Two experimental palatal plates (EPP) were used in this study: one was 1.4mm thick (EPP1), and the other was 2.8mm thick (EPP2). Tongue movements and swallowing sounds were simultaneously recorded. The position of the surface of the tongue was recorded by using ultrasound diagnostic equipment in the sagittal plane. Swallowing tests were performed under three conditions: without EPP (WOE), with EPP1 (WP1), and with EPP2 (WP2). Swallowing index (SI) and tongue contact time (TCT) was calculated. RESULTS: The value of SI was lowest under WOE, and highest under WP2, with a statistically significant difference. There was no statistical significance, however, between SI under WOE and that under WP1. The value of TCT was longest under WOE, and shortest under WP2, with a statistically significant difference. CONCLUSIONS: This investigation suggests that the thickness of a palatal plate influences SI and TCT, which correlate with swallowing function.

Parasympathetic vasodilator fibers in rat digastric muscle.

The present study examined whether parasympathetic vasodilator fibers exist in rat jaw-opening muscles such as the digastric muscle. The mental nerve was stimulated to activate the parasympathetic vasodilator nerve in the digastric muscle. Electrical stimulation of the mental nerve elicited intensity- and frequency-dependent increases of blood flow in this muscle. These increases were markedly reduced by hexamethonium in dose- and time-dependent manners, but pretreatment with phentolamine or propranolol had no effect. Pretreatment with atropine also attenuated the increase in blood flow in digastric muscle. When retrograde fluorogold was injected into the digastric muscle, labeled neurons were observed in the otic ganglion only on the ipsilateral side, but not in the pterygopalatine ganglion of either side. These results indicate that parasympathetic vasodilator fibers originate from cell bodies in the otic ganglion in rat digastric muscle.

Effects of human hair and nail proteins and their films on rat mast cells.

Human hair and nail are valuable materials for producing individual corresponding biocompatible materials. A rapid and convenient protein extraction method (Shindai method) and novel procedures for preparing their protein films from their extracts have been developed using human hair and nail. The effects of the human hair and nail proteins and their films on histamine release from rat peritoneal mast cells were investigated. Both protein solutions and their films, mainly consisting of keratins and matrix proteins, did not induce histamine release from the mast cells. Scanning electron microscopy (SEM) also showed that the mast cells were only slightly affected by adding the human hair and nail proteins or by incubating on their protein films. The IgE-dependent histamine release was inhibited by the hair and nail proteins and their films. Incubation of the mast cells with the hair and nail proteins prior to the addition of the IgE serum resulted in a high inhibition (50%) of the histamine release, while the inhibition was approximately 10% when the protein solutions were mixed with the mast cells after incubation with the IgE serum. These results suggest that the human hair and nail proteins and their films will be useful materials for antiallergic actions.

Influence of mandibular residual ridge shape on masticatory efficiency in complete denture wearers.

PURPOSE: The purpose of this study was to investigate the influence of mandibular residual ridge shape on masticatory efficiency in complete denture wearers. MATERIALS AND METHODS: Twenty-eight complete denture wearers (mean age 75.6 years, SD 4.8) who received their complete denture treatment by one of the authors and had no troubles in daily use were selected. The mandibular residual ridge was evaluated by using a replica of the ridge obtained with heavy-body silicone impression material. The basal area of the replica was measured by a digitizer. The volume and the height of the replica were calculated. Masticatory efficiency in each subject was measured by the sieving method. RESULTS: There was a significant correlation between the masticatory efficiency and basal area, volume, and height of the residual ridge. The basal area showed the strongest correlation. CONCLUSION: The basal area of the denture foundation greatly influenced the masticatory efficiency, suggesting that the masticatory efficiency in complete denture wearers was limited by their own residual ridges and that clinicians should inform their patients about the limitation of the recovery of masticatory ability before the beginning of denture treatment.