Clinical use of duplicate complete dentures: A narrative review.

Most reports on duplicate dentures are introduction to fabrication methods or clinical case reports. Only a few studies have verified their clinical effectiveness; hence, evidence to construct useful clinical guidelines for duplicate denture use is lacking. This review aimed to comprehensively investigate reports on duplicate dentures to accumulate evidences that will contribute to the formulation of clinical practice guidelines. Duplicate dentures are effectively used for impression making and bite registration when fabricating new dentures, thereby reducing the number of clinic visits and treatment time. Duplicate denture can also be used as temporary or new dentures. Older people in whom various adaptive abilities have declined, may find it difficult to adjust to new dentures and experience stress, even if the shape is appropriate. Duplicate dentures, which reproduces the shape of old dentures that they are used to, have the advantage of being more familiar to older people and less stressful. When manufacturing duplicate dentures, digital methods such as milling and three-dimensional printing are superior to conventional methods regarding working time and cost. A notable advantage of the digital method is that the denture shape can be saved as digital data, and the denture can be easily duplicated if lost.

Improvement of drug-induced gingival overgrowth and cerebrovascular related dementia after dental treatments.

Drug-induced gingival overgrowth can occur as a side effect of specific drugs and lead to poor oral function. Appropriate dental management of the overgrowth may improve oral function and improve cognitive deficits after cerebrovascular accidents.

Dental treatment under intravenous sedation prolongs longevity of a fixed prosthesis in patients with intellectual disabilities.

AIMS: This study aimed to assess the longevity of a fixed prosthesis in patients with intellectual disability (ID) and to investigate the risk factors associated with the failure of a prosthesis due to abutment tooth extraction or prosthesis dislodgement or removal. METHODS: We studied past medical records to evaluate the longevity of 315 prostheses that were luted in 76 patients with ID. We calculated the survival rates and assessed 15 variables potentially associated with prosthetic failure using multivariate Cox regression analyses with shared frailty for patients. RESULTS: Three-quarters of our sample population had severe or profound ID. The maximum observation period was 31.0 years, and the corresponding survival ratio was 32.5%; the survival ratio at 10 years was 59.4%. The use of intravenous sedation significantly influenced the success of the prosthesis, with the hazard ratio (HR) being 0.49 times that of conventional treatment without behavior-altering drug therapy. The most significant risk factor for prosthetic failure was age at placement; the HR for patients aged ≥31 years was 2.82 times that for patients aged ≤ 20 years. CONCLUSIONS: In patients with severe ID, appropriate intravenous sedation was effective in prolonging the longevity of a fixed prosthesis.

Direct bonded fixed partial denture with an artificial denture tooth as a pontic.

Background: The present review aimed to investigate the feasibility and clinical effectiveness of a direct bonded fixed partial denture (DBFPD) based on available literature. The efficiency of a DBFPD is mainly affected by the type of artificial denture tooth, the type of luting agent, and the adhesive preparation. Methods: The parameters were reviewed based on the in vitro and in vivo studies conducted. An acrylic resin tooth or a composite resin tooth for removable dentures should be used as the artificial tooth for the pontic. Results: Considering the luting agent, a methyl methacrylate-based resin luting agent, which has low mechanical strength but is capable of plastic deformation and could sustain for a long time, should be used. Appropriate pre-adhesive treatment should be performed on both the artificial and abutment teeth. The cases in which a DBFPD can be applied are limited to one missing anterior tooth, as long as it is not overstressed. Patient cooperation in cases of occlusion seems to be another prerequisite. Conclusion: Knowledge and selection of the material and case indications are essential, and patient cooperation is pertinent in studying the long-term prognosis of a DBFPD.

Evaluation of the effects of three pretreatment conditioners and a surface preparation system on the bonding durability of composite resin adhesive to a gold alloy.

This study aimed to evaluate the effect of three pretreatment conditioners and surface preparations on a composite resin adhesive for a gold alloy. Cast disk specimens were made and bonded with RelyX Unicem luting agent under six surface conditions: 1) polished with No.600 carbide paper, 2) air-abraded with alumina, 3) Alloy Primer metal conditioner was applied after alumina-abrasion, 4) Monobond Plus multipurpose conditioner was applied after alumina-abrasion, 5) M. L. Primer metal conditioner was applied after alumina-abrasion, and 6) Rocatec multipurpose silica-coating system was applied. The bond strengths were determined before and after thermocycling (50,000 cycles). The bond strengths of the alumina-abrasion group were significantly decreased after thermocycling. The Rocatec and M. L. Primer exhibited higher bond strengths than other treatments. The application of metal conditioners and multipurpose surface preparations was recommended for improved bonding between the evaluated adhesive resin and gold alloy.

Longevity of resin-bonded fixed partial dentures made of metal alloys: A review of the literature.

Purpose In this review, we evaluate the survival rate of resin-bonded fixed partial dentures (RBFPDs) made of metal alloys.Methods An electronic search of English peer-reviewed dental literature on PubMed was conducted to identify all publications reporting on RBFPDs made of metal alloys until March 2019. The searched keywords were: bridge OR fixed partial denture OR fixed prosthesis OR fixed prostheses AND resin bonded AND metal OR alloy AND survival OR longevity (RBFPD was not included). Furthermore, the "Related Articles" feature of PubMed was used to identify further references of interest during the primary search. A definitive list of articles was screened to extract qualitative data after the application of the inclusion and exclusion criteria, and the results were analyzed.Results Overall, 977 publications were found through an electronic and manual search, out of which 130 articles were selected after screening based on title and abstract. A total of 52 publications passed the second review phase after assessment for eligibility, from which 24 studies were excluded after full-text screening. Finally, a total of 28 studies were selected.Conclusions The survival rate of RBFPDs differed greatly depending on the type of metal alloy, adhesion system, and observation period assessed, e.g. the 10-year survival rate ranged from 18% to 88%. The wide range of survival rates of the RBFPDs reported indicates that though RBFPD is a reliable prosthesis, it is prone to failure if some processes are not completed.

A prospective clinical evaluation of fixed dental prostheses made of metal alloys in patients with cerebral palsy.

BACKGROUND: In general, the prevalence of caries and other oral and dental issues is increased in patients with disabilities, such as those with cerebral palsy. Providing appropriate dental treatment at a primary dental clinic for patients with cerebral palsy and intellectual disability, among other conditions, is challenging. OBJECTIVE: The objective of this study was to evaluate the longevity and investigate the related prognostic factors of fixed prostheses in patients with cerebral palsy. METHODS: The records of 36 cerebral palsy patients were used for collecting and analyzing data. A total of 155 prostheses made from metal alloys were finally included in this study. Annual failure rates were calculated; patient- and tooth-related variables associated with prosthesis failure were assessed by a multivariate Cox-regression analysis and frailty models to introduce random effects. RESULTS: The 10-year prosthesis survival rate was 62% and the 20-year survival rate was 36%. In terms of prosthesis-related variables, the type of prosthesis had a significant effect, and the hazard ratio of fixed partial dentures was 2.32 times that of single-unit crowns. In terms of patient-related variables, the presence of epilepsy had a significant effect on survival, and the hazard ratio for comorbid epilepsy was 3.76 times that for those without comorbid epilepsy. CONCLUSIONS: Our findings suggested that fixed prostheses placed in patients with cerebral palsy might have a particularly low survival rate in cases with comorbid epilepsy. It might also be important to consider the type and/or design of the prosthesis carefully to ensure a better prognosis.

Study on the preventive effect of ramelteon on the onset of sleep disorder after general anesthesia in patients with autism spectrum disorder: A study protocol.

BACKGROUND: The persistent loss of consciousness caused by general anesthesia without the existence of repeated 90-minute cycles of non-REM and REM sleep might significantly disturb and suppress the cycle of normal physiological sleep in postoperative periods after general anesthesia. Patients with autism spectrum disorders (ASD) with existing circadian rhythm disorder are reported to rapidly deteriorate due to acute sleep disorder during the perioperative period after general anesthesia.A melatonin receptor agonist, ramelteon (Rozerem), which is a sleep cycle regulator, is used as a therapeutic drug for patients with sleep disorders, but there are no studies on the prevention of postoperative sleep disorder after general anesthesia.In this study, we investigate whether prophylactic administration of a sleep-inducing substance, a melatonin receptor agonist, is effective against sleep disorder after general anesthesia in patients with ASD. METHODS/DESIGN: This study is intended for patients with ASD aged 12 years and above who undergo treatment at Nagasaki University Hospital, Isahaya General Hospital Dentistry, and Sasebo City General Medical Center Dentistry and undergo dental treatment under general anesthesia. A melatonin receptor agonist (Rozerem) will be taken 7 days prior and 7 days postsurgery in patients diagnosed with insomnia. A randomized comparison will be made between 2 groups: an experimental group that is additionally administered Rozerem and a control group.The primary endpoint is the incidence of NREM-REM sleep disorders that occur within 3 to 5 days after general anesthesia. The secondary endpoint is the incidence of circadian rhythm sleep disorders (rate of occurrence of sleep-retardation syndrome with drowsiness and strong fatigue). DISCUSSION: Postoperative sleep disorders after general anesthesia has been reported in patients with ASD; however, effective preventive pharmacological treatments have not been established. A sleep cycle regulator, ramelteon (Rozerem), is used as a therapeutic drug for patients with sleep disorders by decreasing the difficulty of falling asleep in insomnia. If sleep disorder can be prevented after the administration of general anesthesia in patients with ASD, we can support social participation while maintaining their quality of life. TRIAL REGISTRATION: The study was registered with the jRCT1071200030.

A Randomized Phase 2 Trial of Antibiotic Prophylaxis Versus No Intervention for Muscle Biopsy in A Neurology Department.

Muscle biopsy can be used to confirm the diagnosis of neuromuscular diseases. However, it is unclear whether antibiotic prophylaxis prior to muscle biopsy is needed to prevent surgical site infection (SSI). We are conducting a phase 2, single-center, open-labeled, prospective randomized trial to clarify the need for antibiotic prophylaxis in patients at low risk for SSI undergoing muscle biopsy. Patients will be randomized to an antibiotic prophylaxis group or a control group, and the incidence of SSI will be compared between the groups. Our findings will clarify the need for antibiotic prophylaxis in this patient population.

Development of Vancomycin Dose Individualization Strategy by Bayesian Prediction in Patients Receiving Continuous Renal Replacement Therapy.

PURPOSE: Vancomycin (VCM) concentration is often out of therapeutic range (10-20 µg/ml) in patients receiving continuous renal replacement therapy (CRRT). The purposes of this study were to develop a practical VCM population pharmacokinetic (PPK) model and to evaluate the potential of Bayesian prediction-based therapeutic drug monitoring (Bayes-TDM) in VCM dose individualization for patients receiving CRRT. METHODS: We developed a VCM PPK model using 80 therapeutic concentrations in 17 patients receiving CRRT. Bayes-TDM with the VCM PPK model was evaluated in 23 patients after PPK modeling. RESULTS: We identified the covariates reduced urine output (RUO, <0.5 ml/kg/h) and effluent flow rate of CRRT for the VCM PPK model. The mean VCM non CRRT clearance (CLnonCRRT) was 2.12 l/h. RUO lowered CLnonCRRT to 0.34 l/h. The volume of distribution was 91.3 l/70 kg. The target concentration attainment rate by Bayes-TDM was higher (87.0%) than that by the PPK modeling period (53.8%, P = 0.046). The variance of the second measured concentrations by the Bayes-TDM was lower (11.5, standard deviation: 3.4 µg/ml) than that by the PPK modeling period (50.5, standard deviation: 7.1 µg/ml, P = 0.003). CONCLUSIONS: Bayes-TDM could be a useful tool for VCM dose individualization in patients receiving CRRT.

The pilot study examining the effects of swallowing position on lung volume fraction and the coordination between respiration and non-nutritive swallowing reflex.

BACKGROUND: Body position might affect the coordination between respiration and swallowing. This study was carried out to test the hypothesis that during swallowing, coordinated movements of muscle groups such as the diaphragm and rectus abdominis muscles are important to control normal swallowing apnea. OBJECTIVE: To investigate this hypothesis, respiratory parameters, swallowing apnea and muscle activity were measured in each of four body positions: sitting position with feet on the floor, 30° reclining position, lateral position, and standing position. METHODS: All measurements were performed in nine healthy subjects. Nasal airflow was measured using a pneumotachometer and muscle activity was measured using an electromyograph. All lung volume fraction parameters were measured using spirometer and swallowing apnea time was calculated. RESULTS: The maximum inspiratory volume was 2.76 ± 0.83 L in the 30° reclining position, which was significantly larger than that in the other positions (p = .0001). The preliminary expiratory volume was 1.05 ± 0.42 L in the 30° reclining position, which was significantly smaller than that in the other positions (p < .0001). The swallowing apnea time during water swallowing was 1.17 ± 0.35 sec in the lateral position and 0.87 ± 0.28 sec in the 30° reclining position, which tended to be longer than the 0.78 sec in the sitting position. CONCLUSION: We conclude that both lateral and reclining positions require a longer period of swallowing apnea compared to the sitting and standing positions. Differences in body position may significantly influence the coordination between respiration and swallowing.

The effect of midazolam administration for the prevention of emergence agitation in pediatric patients with extreme fear and non-cooperation undergoing dental treatment under sevoflurane anesthesia, a double-blind, randomized study.

Background: Sevoflurane is generally the preferred anesthetic agent for general anesthesia in pediatric patients, due to its rapid induction and recovery characteristics. However, it has been recognized that a major complication is emergence agitation when awakening from general anesthesia. The aim of this study was to evaluate the occurrence rate of emergence agitation in the operating room and postoperative recovery area following intraoperative administration of midazolam to pediatric patients under general anesthesia. Patients and methods: One hundred and twenty pediatric patients undergoing dental treatment under sevoflurane anesthesia were enrolled in this study. The patients were divided into three groups (n=40 each in the 0.1 mg/kg midazolam, 0.05 mg/kg midazolam, and control with saline groups). Midazolam or saline was injected intravenously approximately 30 minutes before the end of the dental treatment. We used the Richmond Agitation and Sedation Scale (RASS) to assess the level of sedation and drowsiness at emergence phase in the operating room. We also used the Pediatric Anesthesia Emergence Delirium Scale (PAED) to assess the level of agitation and delirium at the full recovery phase from anesthesia in the recovery area. Results: At the emergence phase, the incidence of emergence agitation in the 0.1 mg/kg midazolam group was significantly lower than in the other groups (p=0.0010). At the recovery phase, there was no significant difference among the three groups. The odds ratio between PAED score and RASS score was 4.0 using logistic regression analysis. The odds ratio between PAED score and Disability was 2.5. Conclusion: Administration of a single dose of 0.1 mg/kg midazolam dose significantly decreases the incidence of severe emergence agitation at the emergence after sevoflurane anesthesia, but not at the recovery phase. Furthermore, the evaluation of sedative and agitation condition using RASS score at emergence from anesthesia is useful to predict occurrence of agitation in the recovery phase.

Fatigue resistance of yttria-stabilized tetragonal zirconia polycrystal clasps for removable partial dentures.

With the rapid development of computer-aided design/computer-aided manufacturing (CAD/CAM) systems, the application of zirconia in removable partial dentures is expected to expand. Clasps composed of zirconia should improve esthetics without inducing the risk of metal allergy. The aim of this study was to examine the fatigue resistance of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) clasps for removable partial dentures. Yttria-stabilized tetragonal zirconia polycrystal and cobalt-chromium (Co-Cr) alloy were prepared using CAD/CAM systems. Specimens were either of the semicircular type or of the flat type, with cross-sectional areas of taper ratios of 0.50, 0.75, and 1.00. All specimens were tested using the cantilever test and the constant displacement fatigue test, and data were analyzed using ANOVA. During the cantilever test, the maximum displacement prior to fracture was greater than the required undercut, and the semicircular-type specimen exhibited a higher fracture load than the flat type. None of the specimens displayed permanent deformation and showed almost the same degree of deformation after fatigue testing. A lower taper ratio was associated with lower average load values and greater displacement. Within the limitations of this study, it was possible to conclude that Y-TZP provides the required undercut and adequate retentive force for removable partial denture clasps. Additionally, Y-TZP and Co-Cr alloy had almost the same degree of deformation even after the simulated lifespan of removable partial dentures.

Technique to Confirm Occlusal Contact Using an Articulating Paper Holder Equipped with Tongue Depressor.

This technical report describes a simple procedure for verifying occlusal contact with the use of a new device that combines the functions of a tongue depressor and an articulating paper holder. Verifying occlusal contact and/or the maxillomandibular relationship record can be expected to be simpler and easier with this device compared to the conventional holder, especially for patients with tongue hypertrophy or obesity and those treated under general anesthesia, among others.

Effects of general anesthesia on postoperative sleep cycles in dentally disabled patients.

AIMS: Although it has been reported that general anesthesia affect the perioperative sleep cycle, no studies have yet evaluated how general anesthesia affects dentally disabled patients. In this study, we investigated the alteration of perioperative sleep cycles in dentally disabled patients receiving dental treatment under general anesthesia. SUBJECTS AND METHODS: The study included 16 patients receiving dental procedures under general anesthesia. Using a sleep monitoring mat, the patients' sleep cycles were measured at home from 5 days before the scheduled surgery date until 5 days after discharge following general anesthesia. The change in all the variables of sleep cycles were analyzed in comparison to the value in preoperative period. Daily differences in these variables were assessed for statistical analysis. RESULTS: The percentage of deep sleep (Stages 3 and 4) decreased significantly on postoperative day 1, and the percentage of light sleep increased. Furthermore, sleep cycles were significantly extended on postoperative day 1. CONCLUSION: The percentage of deep sleep decreased significantly on postoperative day 1 while the percentage of light sleep increased. Sleep cycles were also significantly extended on postoperative day 1. These results reveal that the sleep cycle is somehow affected on the first day following general anesthesia.

Effects of polymerization method on flexural and shear bond strengths of a fiber-reinforced composite resin.

This study investigated the effects of indirect composite polymerization on the postcuring mechanical properties of a fiber-reinforced composite. An indirect composite seated on glass fibers preimpregnated with polymerized monomer was polymerized by 1) photoirradiation using a halogen-fluorescent polymerizing unit for 5 min, 2) method 1 plus secondary heating at 100°C for 15 min, 3) photoirradiation using a metal halide light unit for 60 s, or 4) preliminary polymerization using a halogen light unit for 20 s followed by method 3. After polymerization, the flexural and shear bond strengths of the fiber-reinforced composite were examined, as was the flexural strength of non-fiber-reinforced composite specimens polymerized using the same methods. Among non-fiber-reinforced composite specimens, flexural strength was lower for method 1 than for the other three methods; however, among fiberreinforced composite specimens, the four methods did not significantly differ in flexural strength or shear bond strength. Composite-fiber interface separation without breakage of the fiber after flexural strength testing was not observed in specimens polymerized by methods 2 or 4. In conclusion, use of a conventional unit for high-intensity light irradiation after preliminary irradiation, or light irradiation followed by secondary heating, is recommended for polymerization of composite material seated on polymerized glass fiber.

Bonding durability between acrylic resin adhesives and titanium with surface preparations.

The purpose of the present study was to evaluate the efficacy of pretreatment on the bonding durability between titanium casting and two acrylic adhesives. Cast titanium disk specimens treated with four polymer-metal bonding systems as follow: 1) air-abraded with 50-70 µm alumina, 2) 1)+Alloy Primer, 3) 1)+M.L. Primer and 4) tribochemical silica/silane coating system (Rocatec System). The specimens were bonded with M bond or Super-bond C&B adhesive. The shear bond strengths were determined before and after thermocycling (20,000 cycles). The surface characteristics after polishing, and for the 1) and 4) preparations were determined. The bond strengths for all combinations significantly decreased after thermocycling. The combination of Super-bond C&B adhesive and 2) led to significantly higher bond strength than the other preparations after thermocycling. The maximum height of the profile parameters for the polishing group was lower than other preparations.

Longevity of resin-bonded fixed partial dental prostheses made with metal alloys.

OBJECTIVES: The purpose of this study was to evaluate the clinical performance of resin-bonded fixed partial dental prostheses (RBFPDPs) made with metal alloys. MATERIALS AND METHODS: The retention of 311 RBFPDPs from 226 patients fabricated from 1983 to 2013 using an adhesive resin was clinically evaluated. Partial or complete debonding of the RBFPDP or framework fracture was considered a treatment failure. All data were obtained from clinical examinations, and missing data were censored at the date of the last available information. The effect of the following factors on survival rate were investigated: patient gender, location (maxilla/mandible and anterior/posterior), number of missing teeth, number of abutment teeth, framework structure, type of metal alloy, patient age at the point of cementation, cement type, and distinction of the treating dentist. Data were analyzed with the Kaplan-Meier survival tests, log-rank tests, and Cox regression analyses (α = 0.05). RESULTS: The Kaplan-Meier survival rate was 41.2 % ± 6.5 % (standard error) at 28.8 years (last outcome event). Significant differences were found for patient age and treating dentist (p < 0.05). The risk of failure in younger patients was 1.7 times greater than that in older patients and that of inexperienced dentists was 2.0 times greater than that of dentist experienced and specialized in adhesive dentistry. CONCLUSIONS: When fabricating RBFPDPs for younger patients, mechanical preparation for bonding may be necessary in consideration of the risk for debonding. Experienced dentists may achieve better results. CLINICAL RELEVANCE: Mastery of skills is necessary to ensure excellent prognoses for RBFPDPs.

A direct bonded fixed partial dental prosthesis: a clinical report.

A direct bonded fixed partial dental prosthesis, with a composite resin denture tooth as a pontic, a tri-n-butylborane initiated adhesive resin, and screw posts for reinforcement, was still functioning after an observation period of 20 years. The prosthesis was found to be reliable for long-term clinical use when chemically and mechanically reinforced.

Factors affecting the bond strength of denture base and reline acrylic resins to base metal materials.

OBJECTIVE: The shear bond strengths of two hard chairside reline resin materials and an auto-polymerizing denture base resin material to cast Ti and a Co-Cr alloy treated using four conditioning methods were investigated. MATERIAL AND METHODS: Disk specimens (diameter 10 mm and thickness 2.5 mm) were cast from pure Ti and Co-Cr alloy. The specimens were wet-ground to a final surface finish of 600 grit, air-dried, and treated with the following bonding systems: 1) air-abraded with 50-70-µm grain alumina (CON); 2) 1) + conditioned with a primer, including an acidic phosphonoacetate monomer (MHPA); 3) 1) + conditioned with a primer including a diphosphate monomer (MDP); 4) treated with a tribochemical system. Three resin materials were applied to each metal specimen. Shear bond strengths were determined before and after 10,000 thermocycles. RESULTS: The strengths decreased after thermocycling for all combinations. Among the resin materials assessed, the denture base material showed significantly (p<0.05) greater shear bond strengths than the two reline materials, except for the CON condition. After 10,000 thermocycles, the bond strengths of two reline materials decreased to less than 10 MPa for both metals. The bond strengths of the denture base material with MDP were sufficient: 34.56 MPa for cast Ti and 38.30 for Co-Cr alloy. CONCLUSION: Bonding of reline resin materials to metals assessed was clinically insufficient, regardless of metal type, surface treatment, and resin composition. For the relining of metal denture frameworks, a denture base material should be used.