RESUMEN
STATEMENT OF PROBLEM: Single-implant-retained mandibular overdentures (1-IODs) may be an alternative to 2-IOD for maladaptive denture patients giving comparable satisfaction, lower cost, and shorter treatment times. However, studies evaluating the effect of the number of implants on the strain exerted around the implants of IODs using strain-gauge analysis are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the number of implants on the strain in an IOD under various loading and dislodging conditions. MATERIAL AND METHODS: A mandibular IOD with the Locator attachment system (pink nylon inserts) was fabricated on artificial mucosa. Three implant positions recorded the loading: 1-IOD (mid-anterior), 2-IOD (bilateral lateral incisor), and 3-IOD (mid-anterior and bilateral canine) were prepared. Strain gauges attached to the mid-anterior implant replica for the 1-IOD, the left lateral incisor replica for the 2-IOD, and the anterior and left canine replicas for the 3-IOD. Vertical loads of 50 N were applied to the experimental overdenture in the mid-anterior and right molar and left molar regions. Three dislodging tests were performed in 3 different areas: mid-anterior, posterior, and mid-anterior and bilateral molar. Six measurements were made under each loading and dislodging condition for each IOD (N=6). During the calibration test, the resultant strain measured by strain gauge was converted into a lateral force (F) value by using linear regression: Fanterior-posterior(N)=1.08×strain (µÎµ), Fposterior-anterior(N)=0.192×strain (µÎµ), Fleft-right(N)=0.590×strain (µÎµ), Fright-left(N)=0.560×strain (µÎµ). Statistical analysis was performed by using 1-way ANOVA and the Tukey honestly significant difference test (α=.05). RESULTS: The 3-IOD demonstrated the significantly highest strain under loading and dislodging conditions (P<.05). The 1-IOD demonstrated the significantly highest strain during right-side loading (P<.05). Upon anterior and left-side loading, no significant difference was noted in strain between the 1-IOD and 2-IOD (P=.413, P=.272). Under dislodging conditions, the 1-IOD exhibited the significantly lowest strain (P<.05). CONCLUSIONS: Within the limitations of this study, the 3-IOD demonstrated the highest lateral resistance force during load and dislodge testing, whereas the 1-IOD exhibited the lowest.
Asunto(s)
Implantes Dentales , Retención de Dentadura , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental , Prótesis de Recubrimiento , Humanos , MandíbulaRESUMEN
BACKGROUND: Mandibular overdentures retained by a single implant placed in the midline of edentulous mandible have been reported to be more comfortable and function better than complete dentures. Although single-implant overdentures are still more costly than conventional complete dentures, there are a few studies which investigated whether mandibular single-implant overdentures are superior to complete dentures when patient general satisfaction is compared. The aim of this study is to assess patient general satisfaction with mandibular single-implant overdentures and complete dentures. METHODS: This study is a randomized crossover trial to compare mandibular single-implant overdentures and complete dentures in edentulous individuals. Participant recruitment is ongoing at the time of this submission. Twenty-two participants will be recruited. New mandibular complete dentures will be fabricated. A single implant will be placed in the midline of the edentulous mandible. The mucosal surface of the complete denture around the implant will be relieved for 3 months. The participants will then be randomly allocated into 2 groups according to the order of the interventions; group 1 will receive single-implant overdentures first and will wear them for 2 months, followed by complete dentures for 2 months. Group 2 will receive the same treatments in a reverse order. After experiencing the 2 interventions, the participants will choose one of the mandibular prostheses, and yearly follow-up visits are planned for 5 years. The primary outcome of this trial is patient ratings of general satisfaction on 100âmm visual analog scales. Assessments of the prostheses and oral health-related quality of life will also be recorded as patient-reported outcomes. The secondary outcomes are cost and time for treatment. Masticatory efficiency and cognitive capacity will also be recorded. Furthermore, qualitative research will be performed to investigate the factors associated with success of these mandibular denture types. Clinical outcomes, such as implant survival rate, marginal bone loss, and prosthodontic complications, will also be recorded. DISCUSSION: The results of this randomized crossover trial will clarify whether mandibular single implants and overdentures for edentulous individuals provide better patient general satisfaction when compared to conventional complete dentures. TRIAL REGISTRATION: This clinical trial was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN000017883).
Asunto(s)
Implantes Dentales/efectos adversos , Dentadura Completa/efectos adversos , Prótesis de Recubrimiento/efectos adversos , Arcada Edéntula/terapia , Satisfacción del Paciente , Calidad de Vida/psicología , Estudios Cruzados , Humanos , Mandíbula , Proyectos de InvestigaciónRESUMEN
STATEMENT OF PROBLEM: Fracture of maxillary implant overdentures (IODs) is a frequent complication. However, no studies have examined the effects of clip materials on the stress applied to maxillary IODs. PURPOSE: The purpose of this study was to investigate the effects of clip materials for bar attachments on the stress applied to maxillary IODs without palatal coverage. MATERIAL AND METHODS: This study included finite element analysis and a model study. An edentulous maxillary model with 4 implants and an experimental overdenture with bar attachments was fabricated. Strain gauges were attached on the denture surface adjacent to the end of each clip. Four clip conditions (n=5) were prepared: 3 plastic clips, 1 plastic clip, 3 metal clips, and 1 metal clip. A vertical load of 50 N was applied on the IOD. The maximum principle strain (MPS) was statistically analyzed by 2-way ANOVA and the post hoc Tukey HSD tests with clip materials and clip numbers as factors (α=.05). RESULTS: The greatest stress was observed on the resin surface around the end of the clip on the loaded side. The MPSs between both clip materials (P=.048) and numbers (P<.001) differed significantly on the palatal side of the end of the center clip on the loaded side: the MPSs of the metal clips were significantly larger than those of the plastic clips, and the MPS of 1 clip was significantly larger than for 3 clips. CONCLUSIONS: The stress around plastic clips tended to be lower than that around metal clips.