Yasuhiro Nishi

Dry mouth and denture plaque microflora in complete denture and palatal obturator prosthesis wearers.

OBJECTIVE AND BACKGROUND The purpose of this study was to investigate the association of dry mouth with denture plaque microflora in patients with palatal obturator prostheses from the viewpoint of infection control. METHODS Thirty palatal obturator prosthesis wearers were compared with 30 healthy maxillary complete denture wearers. Dry mouth was examined using a moisture-checking device and was diagnosed by the measured moisture levels. Denture plaque was collected by rubbing the mucosal surface of the denture with a swab; collected microorganisms were cultured and identified using culture-dependent methods. The number of colonising microorganisms and prevalence of microorganisms were examined according to the type of prostheses and presence of dry mouth using nonparametric tests and frequency analysis (α = 0.05). RESULTS The prevalence of Candida spp. and Staphylococcus spp. in palatal obturator prostheses was significantly higher than that in complete dentures. In palatal obturator prostheses, the total number of colonising microorganisms showed no significant differences between the groups with and without dry mouth on each side of the prostheses. However, the prevalence of Candida spp. and Staphylococcus spp. in the group with dry mouth was significantly higher than that in the group without dry mouth. The number of microorganisms and moisture levels of palatal obturator prosthesis wearers showed a significantly negative correlation with Candida spp. and Staphylococcus spp., but a positive correlation with Neisseria spp. CONCLUSION It was concluded that palatal obturator prosthesis wearers with a dry mouth have greater colonisation by Candida spp. and Staphylococcus spp. than do complete denture wearers.

Relationship between medical treatment and oral dryness diagnosed by oral moisture-checking device in patients with maxillofacial prostheses.

PURPOSE This study aimed to examine the relationship between oral dryness and medical treatment (medication, radiotherapy) for patients with maxillofacial prostheses. METHODS Sixteen patients with maxillofacial prostheses were examined according to the following procedure. For evaluating oral dryness, oral moisture was measured at the lingual mucosa and the right and left buccal mucosa using a Moisture Checker Mucus. The mean value of each measurement was recorded as the moisture value (%). A value of 29% was used as a reference value to divide patients into a normal group and an oral dryness group. Patients with a moisture value of more than 29% were classified as normal. The clinical histories of the patients (including their current medication use and radiotherapy history-dose of radiation and period after radiation) were surveyed from their clinical records. Patients rated themselves on their feelings for oral dryness using a faces scale. RESULTS The moisture value was significantly lower in the oral dryness group than the normal group. There was a significant difference in moisture values between the number of patients with and without radiotherapy, but not patients with and without medications. The moisture value had a significant negative correlation with the dose of radiation and a positive one with the period after radiation. The score of faces scale showed a significant negative correlation with moisture value. CONCLUSION The patients with maxillofacial prostheses who had undergone radiotherapy need moisture retention because of oral dryness depending on the dose of radiation and the period after radiation.

Survival of microorganisms on complete dentures following ultrasonic cleaning combined with immersion in peroxide-based cleanser solution

OBJECTIVES To compare ultrasonic cleaning combined with immersion in a commercially available peroxide-based cleanser solution (Polident(®) ) with other denture cleaning methods, we examined the quantity of micro-organisms that survived on dentures before and after various cleaning methods. SUBJECTS AND METHODS One hundred complete dentures belonging to 50 nursing home residents (mean age, 84.6 years) were randomly assigned to five groups according to the cleaning method employed: (A) immersion in Polident(®) solution alone, (B) brushing with water, (C) ultrasonic cleaning with water, (D) method (A) followed by method (B) and (E) ultrasonic cleaning combined with immersion in Polident(®) solution. Before and after the dentures had been cleaned, denture biofilm was collected from the mucosal surface of each lateral half of the examined dentures. The collected micro-organisms were cultured, presumptively identified by standard methods and quantified. Comparisons between the five cleaning methods were carried out using the Kruskal-Wallis test and Dunns multiple comparisons test. RESULTS The denture cleaning methods involving the use of Polident(®) solution (methods A, D and E) were significantly more effective at denture disinfection than the other methods (p < 0.05); in particular, the quantity of Candida spp. was lowest after method E (median, 0.00; significantly lower than those observed after methods A, B and C; p < 0.05). CONCLUSION It was concluded that ultrasonic cleaning combined with immersion in a peroxide-based cleanser solution effectively reduces the quantity of micro-organisms surviving on dentures and is a suitable method for elderly individuals who find brushing their dentures difficult.

Examination of denture-cleaning methods based on the quantity of microorganisms adhering to a denture.

OBJECTIVES To investigate effective denture-cleaning methods, we examined the relationships between the quantity of microorganisms adhering to dentures and the use of a denture brush and the frequency of use of a denture cleanser. SUBJECTS AND METHODS Denture plaque was collected from the mucosal surface of the examined dentures, which were 142 and 80 upper and lower complete dentures, respectively, worn by 96 outpatients (mean age: 71.9 years) of a university hospital and 41 nursing home residents (mean age: 84.8 years). The collected microorganisms were counted in terms of isolated representative colonies that were cultured and identified using standard methods. The use of a denture brush, the frequency of use, and the type and soaking time of denture cleansers as denture-cleaning methods were surveyed. RESULTS The quantity of microorganisms was significantly lower in dentures of denture brush users than in those of non-users in the outpatients (p < 0.01, Mann-Whitney U test). The quantity of microorganisms was significantly lower in the dentures of outpatients who used a denture cleanser daily or 3-4 times a week than in those who used one once or less per month and in the dentures of nursing home residents who used one daily than in those who used one at other frequencies (p < 0.05, Kruskal-Wallis test, followed by Dunns Multiple Comparison test). CONCLUSION Within the limitations of this study, it was concluded that the use of a denture brush and daily use of denture cleanser should be recommended to complete dentures wearers as denture-cleaning methods that effectively reduce the quantity of microorganisms adhering to dentures.

Relationship between symptoms of dryness and moisture levels in patients with maxillofacial prostheses

PURPOSE This study aimed to examine the relationship between symptoms of dry mouth and the moisture levels in patients with maxillofacial prostheses. METHODS Dry mouth of 30 patients with maxillofacial prostheses was examined by direct measurement of oral moisture and subjective symptoms of dry mouth were surveyed using Kakinokis questionnaire. Oral moisture was measured five times at each of the lingual mucosa and the right and left buccal mucosa using Moisture Checker Mucus and the mean value was calculated. Using a value of 29% as a reference, patients were classified as normal when the moisture value was 29%, or more, or with dry mouth if the value was when less than 29%. RESULTS The moisture levels of the patients with subjective symptoms of dry mouth were significantly lower than those of the patients without symptoms of dry mouth at each of the lingual and buccal mucosa. The moisture level of the lingual mucosa was significantly lower than that of buccal mucosa in the group reporting subjective symptoms of dry mouth, but not in those without symptoms. CONCLUSION These results suggest that the symptom of dry mouth is corresponding to the moisture level and the moisture level of the lingual mucosa is associated with symptoms of dryness in patients with maxillofacial prosthesis.

Roles of the artificial tooth arch during swallowing in edentates

PURPOSE This study aimed to clarify the role of the artificial tooth arch (ATA) during swallowing in edentates. METHODS The tongue pressures, activities of the masseter and suprahyoid muscles, and laryngeal and mandibular movements when swallowing saliva, water, pudding, and corned beef were measured simultaneously using experimental dentures with and without an ATA. We analysed the maximum magnitudes of muscle activities and tongue pressures (MAmax and TPmax, respectively), the times from reaching MAmax and TPmax to laryngeal movement (TLM-MAmax and TLM-TPmax, respectively), and the vertical mandibular position. RESULTS The MAmax of the masseter muscle and TPmax were significantly greater with the ATA than without the ATA (p<0.05). However, MAmax of the suprahyoid muscles was not significantly different in the conditions with and without the ATA. TLM-TPmax was significantly longer without the ATA than with the ATA (p<0.05) but the TLM-MAmax of the suprahyoid and masseter muscles were not significantly different with and without the ATA. The MAmax of both suprahyoid and masseter muscles and the TPmax were significantly greater, and TLM-TPmax was significantly longer when swallowing corned beef than other materials (p<0.05). The intermaxillar distance and the range of measured mandibular position at the time of swallowing were shorter and wider in the absence of the ATA than with it. CONCLUSION The present study shows that during swallowing the ATA supports the function of the tongue to perform skillful movements for the smooth passage of food to the oropharynx and the elevation of the larynx by maintaining the mandible position constant near the intercuspal position.

Influence of an antidiabetic drug on biomechanical and histological parameters around implants in type 2 diabetic rats.

Objectives:Type 2 diabetes mellitus (DM) has a deleterious effect on dental implant integration into alveolar bone, thought to arise from impaired osteoblast function and consequent reduced bone turnover. However, whether controlling blood glucose with antidiabetic drugs is sufficient to improve implant integration is unclear. This study was designed to evaluate implant integration using diabetic rats with/without an antidiabetic drug. Materials and Methods:Titanium screws were surgically implanted in each tibia of 20 Goto-Kakizaki (GK) rats and 5 nondiabetic control rats. After 3 or 9 weeks, osseointegration was determined by testing the removal torque required to displace the screw and by histological analysis of various parameters of bone formation. Results:Removal torque was significantly higher in the nondiabetic control group than in GK rats, irrespective of whether the GK rats had received voglibose. Histology revealed that single-labeled surface area was still high in the GK rats at 9 weeks but had peaked and diminished in control rats. Bone-implant contact area was reduced in GK rats. Conclusions:Despite controlling blood glucose, voglibose was unable to reverse the bone metabolic effects of DM.

Use of a Magnetic Attachment to Retain an Obturator Prosthesis for an Osseous Defect

Tooth loss accompanied by a massive defect of the alveolar bone can cause serious problems such as food deposit and esthetic impairment. This report describes procedures for the fabrication of an osseous defect obturator prosthesis connected to a fixed partial denture by a magnetic attachment along with the clinical outcome.

Comparison of a saliva wetness tester and a moisture-checking device in patients with maxillary obturator prostheses

OBJECTIVE Examination of dry mouth in postoperative oral tumour patients should ideally be performed simply and quickly at the chair side. Moisture-checking devices and saliva wetness testers are available for such moisture measurement. Previous studies have reported that moisture-checking devices are useful to examine dry mouth in patients with maxillary obturator prostheses. However, because the measurement principles of saliva wetness testers differ from those of moisture-checking devices, diagnosis by the two devices may result in diagnostic disagreement. The purpose of the present study was to compare the usefulness of a saliva wetness tester with a moisture-checking device for patients with maxillary obturator prostheses. METHODS Oral moisture was measured with a moisture-checking device and a saliva wetness tester in 30 subjects with maxillary obturator prostheses. These measurements were performed five times at the lingual mucosa, and mean values of each measurement were calculated. The reference value for moisture measurements with the moisture-checking device was 29%, and that with the saliva wetness tester was 3 mm. Subjects were classified as having dry mouth when their moisture measurements were less than the reference values. RESULTS The diagnostic results of the saliva wetness tester were in agreement with those of the moisture-checking device. The respective moisture measurements showed a significant positive correlation (r=0.88, p<0.01). CONCLUSION The results of the present study demonstrate that saliva wetness testers are as useful as moisture-checking devices to examine dry mouth in patients with maxillary obturator prostheses.

Fabrication of a Movable Obturator Following Maxillary Reconstruction with Slit‐Shaped Fenestration

Extensive maxillary resection has generally been reconstructed with free skin flaps. Because drooping of the transferred flap causes instability of the obturator prosthesis, maxillary reconstruction often incorporates a slit-shaped oronasal fenestration. Although obturator prostheses for edentulous patients are stabilized with the help of oronasal slits, those for dentate patients are unstable because of flap mobility, resulting in a harmful lateral force exerted on the abutment teeth, causing dislodging of the denture. This report evaluates the benefits of a movable obturator prosthesis for a 60-year-old dentulous patient with maxillary sinus carcinoma. The patient underwent left-sided total maxillectomy, and the defect was reconstructed with a slit-shaped fenestration using a rectus abdominis flap. A conventional obturator prosthesis was inserted; however, drooping of the flap caused instability of the obturator, resulting in nasal regurgitation and fracture of the clasp. To solve this problem, we designed an obturator prosthesis with a movable connection consisting of a ball attachment (patrix) in the metal base and a socket (matrix) in the obturator, which acted as a stress breaker against the harmful force exerted by the flap. Application of this movable obturator prosthesis was a useful solution for a compromising situation created by the surgical procedure. No clinical disorders were observed at the 3-year follow-up.