Prosthetic Maintenance Research Articles

COMPARING PATIENT SATISFACTION, RETENTIONAND MAINTENANCE FOR DIFFERENT SOLUTIONS OF MIDLINE FRACTURE OF IMPLANT RETAINED MANDIBULAR OVERDENTURES

Purpose: The purpose of this study was to evaluate Patient Satisfaction, Retention and Maintenance of Repaired midline fracture Implant Retained Mandibular Overdentures by different methods of repair: a) Direct re-assembly of the denture b) Reinforcement of the fitting surface with a metal framework.Materials and methods: 45 completely edentulous patients seeking for implant installation in the mandible were included in this study. All patients had received single midline implant & a stud attachment; 3-4 months after implant installation. Patients were rehabilitated with implant retained overdentures. Bone height changes, retention and patient satisfaction were evaluated at regular recall visits for one year. 14 patients had reported midline fracture of their mandibular overdentures at the follow up period from 3 to 6 months. The 14 patients were randomly divided in two groups; Group (a): Included seven patients had the fractured denture repaired by direct reassembly using self- cured acrylic resin. Group (b): Included seven patients; had the fractured denture reinforced with a metal framework embedded in the fitting surface of the denture. Patient satisfaction, overdenture retention, and prosthetic maintenance were assessed after dentures repair for patients of the two groups. Evaluation was carried-out at the day of dentures insertion after repair, 2 weeks, 3 months and 1 year after dentures’ repairResults: The results of this study had revealed that Group (b) patients rehabilitated with (Dentures repaired by Reinforcing metal framework) had reported significant improvement in the patients satisfaction, significant decrease in the prosthetic maintenance required after 1 year follow-up compared to patients of Group:(a) patient rehabilitated with (Dentures repaired with direct reassembly using self cure acrylic resin). After 1 year follow up, there was no significant difference in the mean values of retention in both studied groups. Conclusions: Within the limitations of the present study; the following conclusions may be achieved: For a single implant retained mandibular overdenture, midline fracture may better repaired by reinforcement of denture base with a metal framework embedded in the fitting surface of the denture. Metal reinforcement may increase the rigidity of the overdenture, improve the patient satisfaction and may decrease the number of visits required for maintenance.

PATIENT SATISFACTION AND PROSTHETIC MAINTENANCE WITHIN-SUBJECTS TREATED WITH CONVENTIONAL COMPLETE DENTURE AND TELESCOPIC IMPLANT OVERDENTURES

Purpose: the aim of this study was to compare the patient satisfaction and prosthetic maintenance with conventional complete denture versus telescopic overdenture for the same patient.Materials and method: Eight completely edentulous male patients were selected to receive complete dentures for six months. after 6 months period all the patients received four interforaminal implants followed by construction of telescopic overdenture. during the two designs periods both patient satisfaction (VAS) and proshetic maintenance were analysed.Results: The obtained data revealed that the parameters of VAS for group II (Telescopic overdentures) were significantly higher for items 1,3,4 and 6 (satisfaction, speech, stability and chewing ability) as p- value is less than 0.001. However, the ratings for the same group were significantly lower for items 2, 5, 7and 8, that is, comfort with the denture, handling of dentures, metallic taste and ease of hygiene procedure (p <.001) as compared with the groupI (conventional complete dentures). The overall number of maintenance interventions and service provided was equal to 8 in group I and to 9 in group II, respectively. Table 2 gives an overview of the maintenance performed for both groups. more interventions were counted for group I, regarding items 10,11, and 12 (sore spots, relining and occlusal adjustments).While there were more maintenance interventions counted for group II, regarding items 6,9.and 14 (denture base resin fracture, changing the denture design and excessive tooth wear). But regarding the rest of items, there was no maintenance intervention at all for both groups.Conclusion: Within the limitations of this study the following conclusions can be made:1. Edentulous patients who selected and included in this study were satisfied with both designs, however mandibular telescopic overdentures showed significant improvement in visual analouge scale regarding overall satisfaction, speech, stability and chewing ability compared to mandibular conventional complete dentures worn for the same period (6 months).2- Overall prosthetic maintenance required for telescopic overdenture is slightly more than that needed for conventional dentures.

Mini dental implants retaining mandibular overdentures: A dental practice-based retrospective analysis

PurposeThe purpose of this study was to assess the survival of mini dental implants (MDI) and to measure prosthetic maintenance needs in a dental practice-based setting. MethodsPatients with mandibular removable dentures were provided with MDI to improve denture retention. Complications and maintenance were analyzed by use of patient records and evaluated with Kaplan–Meier curves and the log rank test at a significance level of 0.05. ResultsNinety-nine MDI were placed in 25 patients (mean age: 72 years). Two MDI fractured during placement and eight implants failed during the first weeks. No more implants were lost for up to seven years, resulting in 92% survival. Implant survival differed significantly depending on whether the maxilla was provided with complete dentures (94.9%) or with partial dentures (81%). All prostheses were in use at the time of data extraction. Denture base fractures were observed in six cases, an incidence of fractures of 24%. Some minor intervention was necessary: one resin tooth fractured, retention rings were changed in five cases, and repeated relining was required for 16% of the dentures. ConclusionsAfter mid-term observation, survival of MDI was good. However, the incidence of denture base fractures and of minor prosthetic complications should not be under-estimated.

There is No Evidence on the Effect of the Attachment System on Implant Survival Rate, Overdenture Maintenance, or Patient Satisfaction

Attachment systems for mandibular implant overdentures: a systematic review. Kim HY, Lee JY, Shin SW, Bryant SR.J Advanced Prosthodont 2012;4(4):197-203. Ahmed Yaseen Alqutaibi, BDS, MDSc, PhD(c) To address treatment outcomes depending on attachment systems for two-implant mandibular-supported overdentures in terms of (1) implant survival rate, (2) prosthetic maintenance and complications, and (3) patient satisfaction. Systematic review Level 2: Limited-quality, patient-oriented evidence Grade B: Inconsistent, limited-quality patient-oriented evidence.

Patient satisfaction and prosthetic aspects with mini‐implants retained mandibular overdentures. A 5‐year prospective study

This study aimed to evaluate patient satisfaction and prosthetic aspects during a 5-year prospective clinical study of mini dental implants (MDIs) retaining mandibular overdentures. This observational prospective clinical study was conducted on a group of completely edentulous patients (n=28) with retention problems of conventional mandibular dentures. All patients received new maxillary and mandibular conventional dentures. A total of 112 MDIs (four per patient) were inserted using the flapless surgical approach and immediately loaded by the new mandibular dentures (overdentures). Patients indicated satisfaction with their prosthesis using a questionnaire and a visual analogue scale (VAS). Patient satisfaction and prosthetic complications were recorded 6months (T6m ), 1 (T1), 3 (T3), and 5 (T5) years after overdenture insertion. The patient satisfaction with eating (hard/soft) food (P<0.001), talking (P<0.001), appearance (P=0.001), comfort (P<0.001), healing process (P=0.013), socialization (P<0.001), stability/retention of mandibular dentures (P=0.001), ease of oral hygiene (P=0.008), and ease of handling the dentures (P<0.001) increased significantly with time. After 5years, the most common complication was wear/damage of O/rings (n=235), O/ring replacement (n=125), maxillary denture relining times (n=13), worn teeth (n=10), overdentures relines (n=10), detachment of the metal housings (n=9), and fracture of mandibular overdentures (n=8). Mucositis, soreness, and decubitis ulcer under overdenture occurred most often at T6m and decreased significantly with time (P=0.002, 0.005, and 0.024, respectively). Within the limitations of this clinical study, patient satisfaction with mini-implant retained mandibular overdentures increased significantly with time. However, this treatment required a considerable amount of prosthetic maintenance and repair after 5years of service.

A 5-Year Randomized Trial to Compare 1 or 2 Implants for Implant Overdentures

The hypothesis of this 5-y randomized clinical trial was that there would be no significant difference in the satisfaction of edentulous participants with removable complete overdentures attached to 1 or 2 mandibular implants. Secondary aims were to test changes in satisfaction between and within the groups from baseline to 5 y and differences between the groups in implant survival and prosthodontic maintenance over 5 y. Each of the 86 participants (mean age, 67 y) was randomly allocated to receive either 1 implant in the midline (group 1) or 2 implants in the canine areas (group 2) attached to a mandibular overdenture opposing a maxillary complete denture. Satisfaction was self-assessed by participants on a visual analog scale at baseline prior to implants, as well as at 2 mo and 1, 3, and 5 y with implant overdentures, whereas implant survival and prosthodontic maintenance were assessed by clinical examination. After 5 y, 29 participants in group 1 and 33 in group 2 were available, with most dropouts due to death. Satisfaction with the implant denture after 5 y was significantly (P < 0.001) higher than at baseline in both groups and remained with no significant difference (P = 0.32) between the groups. No implants failed in group 1 but 5 failed before loading in 4 participants in group 2. Most participants required maintenance or occasionally denture replacement, and although differences between the groups were not statistically significant, group 1 experienced almost twice as many fractured dentures usually adjacent to the implant attachment. We conclude that there were no significant differences after 5 y in satisfaction or survival of implants with mandibular overdentures retained by 1 implant or 2 implants. Additional research is required to confirm long-term treatment effectiveness of single-implant dentures and the implications of prosthetic maintenance with implant overdentures (ClinicalTrials.gov: NCT02117856).

Clinical Outcome of Double Crown-Retained Mandibular Removable Dentures Supported by a Combination of Residual Teeth and Strategic Implants.

There is a lack of data regarding the clinical outcome of removable partial dentures (RPDs) supported by a combination of residual natural teeth and implants placed in strategic positions. The aim of the present case series was to conduct a retrospective investigation of the clinical outcome of mandibular tooth-implant-retained partial dentures (TIRPD) rigidly retained via telescopic double crowns. Between 1999 and 2010, 18 patients with reduced residual dentition (1 to 3 natural abutment teeth) and in need of an RPD received 1 to 3 implants in strategic positions for support of the removable prostheses. All TIRPDs were rigidly retained by telescopic crowns according to the Marburg Double Crown (MDC) technique; all prostheses were placed in a private practice. Tooth/implant survival and success rates, prosthetic maintenance requirements, and peri-implant parameters were analyzed retrospectively using patient records and clinical examinations during the final recall appointments. Only patients attending at least annual supportive post-implant hygiene therapy visits (SIT) were included. After a mean functional period of 5.84 ± 3 years (range: 3.01-12.21), 14 patients with 14 dentures supported by 24 implants and 27 teeth (mean number of abutments: 3.6) were available for assessment. Four teeth (survival rate: 85.19%) and no implants (survival rate: 100%) were lost. Peri-implantitis was observed around one implant (4.17%). All 14 dentures were functional (survival rate: 100%) and required only limited maintenance (i.e., screw loosening, acrylic resin fracture repairs, relining) amounting to 0.086 treatments per patient per year (T/P/Y). Within the limitations of this case series, it can be concluded that TIRPDs retained via MDCs might represent a viable treatment option in mandibles with few remaining abutment teeth. Further long-term clinical evaluations with a greater sample size are needed for a more detailed evaluation of this treatment concept.

Six-year clinical outcome of single implant-retained mandibular overdentures--a pilot study.

The aim of this prospective pilot study was to evaluate the prosthodontic maintenance as well as the implant outcome of single implant-retained mandibular overdentures over an observation period of 6years. Eleven edentulous patients received one single implant in the midline of the mandible. Denture bases were temporarily relined and 2months later provided with a ball attachment for implant retention. Implant related parameters and prosthodontic maintenance interventions were assessed 4weeks after implant loading and then once a year. Over a mean observation period of 75.9months, no implant was lost. The most frequent prosthetic maintenance intervention was activation of the matrix due to loss of retention, followed by exchange of the female part. Eight denture bases had to be repaired after a fracture in the midline area. Within the limitations of this preliminary clinical study, the concept of a single midline implant to retain a mandibular complete denture was a successful treatment option for elderly edentulous patients.

The single midline implant in the edentulous mandible: a systematic review.

The concept of a single midline implant retaining a complete mandibular denture is controversially discussed among experts. Studies are rare in the literature, and commonly accepted recommendations for this treatment options are not available. This systematic literature review was performed to give an overview over the current literature on the single midline implant therapy for the edentulous mandible and to reveal whether this treatment option might be an alternative to commonly accepted treatment modalities with more implants. A review of the literature published until 24th of May 2013 was conducted to identify in vivo studies on the single midline implant concept with a mean follow-up time of at least 3 months. From the electronic search, 11 studies were finally included. After an observation period of 3-60 months, the implant survival rate ranged from 62.5 to 100 %. The most frequent prosthetic maintenance intervention was "activation of the matrix" followed by "repair of fractured denture base." The concept of one single midline implant to retain a mandibular complete denture can be an alternative, especially for elderly patients. Immediate loading of the implants should be avoided, and the way of integrating the matrix into the denture base should be carefully considered.

Standardizing the evaluation criteria on treatment outcomes of mandibular implant overdentures: a systematic review.

PURPOSEThe aim of this review was to analyze the evaluation criteria on mandibular implant overdentures through a systematic review and suggest standardized evaluation criteria.MATERIALS AND METHODSA systematic literature search was conducted by PubMed search strategy and hand-searching of relevant journals from included studies considering inclusion and exclusion criteria. Randomized clinical trials (RCT) and clinical trial studies comparing attachment systems on mandibular implant overdentures until December, 2011 were selected. Twenty nine studies were finally selected and the data about evaluation methods were collected.RESULTSEvaluation criteria could be classified into 4 groups (implant survival, peri-implant tissue evaluation, prosthetic evaluation, and patient satisfaction). Among 29 studies, 21 studies presented implant survival rate, while any studies reporting implant failure did not present cumulative implant survival rate. Seventeen studies evaluating peri-implant tissue status presented following items as evaluation criteria; marginal bone level (14), plaque Index (13), probing depth (8), bleeding index (8), attachment gingiva level (8), gingival index (6), amount of keratinized gingiva (1). Eighteen studies evaluating prosthetic maintenance and complication also presented following items as evaluation criteria; loose matrix (17), female detachment (15), denture fracture (15), denture relining (14), abutment fracture (14), abutment screw loosening (11), and occlusal adjustment (9). Atypical questionnaire (9), Visual analog scales (VAS) (4), and Oral Health Impact Profile (OHIP) (1) were used as the format of criteria to evaluate patients satisfaction in 14 studies.CONCLUSIONFor evaluation of implant overdenture, it is necessary to include cumulative survival rate for implant evaluation. It is suggested that peri-implant tissue evaluation criteria include marginal bone level, plaque index, bleeding index, probing depth, and attached gingiva level. It is also suggested that prosthetic evaluation criteria include loose matrix, female detachment, denture fracture, denture relining, abutment fracture, abutment screw loosening, and occlusal adjustment. Finally standardized criteria like OHIP-EDENT or VAS are required for patient satisfaction.

Outcome of Treatment of Implant-Retained Overdenture in Patients With Extreme Mandibular Bone Resorption Treated With Bone Grafts Using a Modified Tent Pole Technique

To evaluate the outcome (prosthetic maintenance, survival of implants, patient satisfaction, and quality of life) of prosthetic treatment using an implant-retained overdenture and a modified tent pole procedure for severe mandibular resorption. Seventeen edentulous patients (mean age, 68 yr; range, 54 to 77 yr) with severely resorbed mandibles were treated with autogenous bone grafts using a modified tent pole technique and implant overdentures. A bar was used to splint the implants and the final prostheses with implant connection were completed approximately 7 months after surgery. The mean follow-up time was 5 years (1.5to 7.4 yr). Patients filled out the Oral Health Impact Profile-14 questionnaire concerning their oral health-related quality of life, and then panoramic radiographs were taken during clinical examination. The stability of the overdenture was good in 58.8% of cases and retention was good in 64.7%. The most usual prosthetic complication was loosening of the attachment component, which occurred in 7cases (41.2%). The amount of plaque and bleeding was more remarkable on the lingual surface of the implants and less remarkable on the buccal surface. Pocket depth around the implants seemed to correspond to intraoral implantation. The radiographs depicted excellent grafted bone survival. The patients' oral health-related quality of life was found to be good after treatment. Implant placement with bone grafting using a modified tent pole technique enables the achievement of a good prosthetic solution and the rehabilitation of occlusion, thereby improving the functionality of the prostheses and quality of life.

A Systematic Review of the Clinical Performance of Tooth‐Retained and Implant‐Retained Double Crown Prostheses with a Follow‐Up of ≥3 Years

The objective of this review was to systematically screen the literature for data related to the survival and complication rates observed with dental or implant double crown abutments and removable prostheses under functional loading for at least 3 years. A systematic review of the dental literature from January 1966 to December 2009 was performed in electronic databases (PubMed and Embase) as well as by an extensive hand search to investigate the clinical outcomes of double crown reconstructions. From the total of 2412 titles retrieved from the search, 65 were selected for full-text review. Subsequently, 17 papers were included for data extraction. An estimation of the cumulative survival and complication rates was not feasible due to the lack of detailed information. Tooth survival rates for telescopic abutment teeth ranged from 82.5% to 96.5% after an observation period of 3.4 to 6 years, and for tooth-supported double crown retained dentures from 66.7% to 98.6% after an observation period of 6 to 10 years. The survival rates of implants were between 97.9% and 100% and for telescopic-retained removable dental prostheses with two mandibular implants, 100% after 3.0 and 10.4 years. The major biological complications affecting the tooth abutments were gingival inflammation, periodontal disease, and caries. The most frequent technical complications were loss of cementation and loss of facings. The main findings of this review are: (I) double crown tooth abutments and dentures demonstrated a wide range of survival rates. (II) Implant-supported mandibular overdentures demonstrated a favorable long-term prognosis. (III) A greater need for prosthetic maintenance is required for both tooth-supported and implant-supported reconstructions. (IV) Future areas of research would involve designing appropriate longitudinal studies for comparisons of survival and complication rates of different reconstruction designs.

No difference between splinted and unsplinted implants to support overdentures

The Cochrane Central Register of Controlled Trials (CENTRAL) and Medline (PubMed) together with handsearching of a range of relevant journals. Studies were screened by two authors and randomised clinical trials, prospective and retrospective cohort studies with a mean follow-up of at least three years were included. Articles published in English or German were considered. Information on the survival rates of the implants and of the implant-supported reconstructions as well as on the biological and technical complications was extracted and a qualitative synthesis conducted. Twelve studies were included of which six were randomised controlled trials. After three years there was no difference in implant survival rates between splinted and unsplinted design. Most of the included studies noted that the unsplinted design needs more prosthetic maintenance. No significant difference in the peri-implant outcome between splinted and unsplinted design was found. In more of the studies that considered patient satisfaction, no significant difference in the preference of the patients was reported. Within the limits of this systematic review, it is concluded that there was no significant difference between the two different designs of implant-supported overdentures with respect to the soft tissue health status or patient satisfaction, although the bar-supported overdentures have been shown to need less prosthetic maintenance.

Attachment systems for mandibular implant overdentures: a systematic review

PURPOSEThe aim of this systematic review was to address treatment outcome according to attachment systems for mandibular implant overdentures in terms of implant survival rate, prosthetic maintenance and complications, and patient satisfaction.MATERIALS AND METHODSA systematic literature search was conducted using PubMed and hand searching of relevant journals considering inclusion and exclusion criteria. Clinical trial studies on mandibular implant overdentures until August, 2010 were selected if more than one type of overdenture attachment was reported. Twenty four studies from 1098 studies were finally included and the data on implant survival rate, prosthetic maintenance and complications, patient satisfaction were analyzed relative to attachment systems.RESULTSFour studies presented implant survival rates (95.8 - 97.5% for bar, 96.2 - 100% for ball, 91.7% for magnet) according to attachment system. Ten other studies presented an implant survival rate ranging from 93.3% to 100% without respect to the attachment groups. Common prosthetic maintenance and complications were replacement of an assay for magnet attachments, and activation of a matrix or clip for ball or bar attachments. Prosthetic maintenance and complications most commonly occurred in the magnet groups. Conflicting findings were found on the rate of prosthetic maintenance and complications comparing ball and bar attachments. Most studies showed no significant differences in patient satisfaction depending upon attachment systems.CONCLUSIONThe implant survival rate of mandibular overdentures seemed to be high regardless attachment systems. The prosthetic maintenance and complications may be influenced by attachment systems. However patient satisfaction may be independent of the attachment system.

Number of implants for mandibular implant overdentures: a systematic review

PURPOSEThe aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction.MATERIALS AND METHODSA systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants.RESULTSSix studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants.CONCLUSIONThe implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants.

To splint or not to splint oral implants in the implant-supported overdenture therapy? A systematic literature review

The objective of this systematic review was to assess the influence of splinted and unsplinted oral implants in the mandibular and maxillary implant-supported overdenture therapy, concerning the implant survival, the peri-implant parameters, the prosthetic complications and the patient satisfaction. An electronic MEDLINE search complemented by manual searching was conducted to identify randomized clinical trials, prospective and retrospective cohort studies on implant-supported overdentures with a mean follow-up of at least 3 years. Twelve studies from an initial yield of 1022 titles were finally selected and data were extracted. After an observation period of more than 3 years, there was no difference in implant survival rates between splinted and unsplinted design. From most of the investigations included in this study, it was mentioned that the unsplinted design needs more prosthetic maintenance. In more of the studies that were dealing with the satisfaction of the patients wearing implant-supported overdentures, no significant difference in the preference of the patients was reported. No significant difference in the peri-implant outcome between splinted and unsplinted design was found. Within the limits of this systematic review, it is concluded that there was no significant difference between the two different designs of implant-supported overdentures with respect to the soft tissue health status or patient satisfaction, although the bar-supported overdentures have been shown to need less prosthetic maintenance.

Mandibular implant overdentures followed for over 10 years: Patient compliance and prosthetic maintenance

PURPOSE: The mandibular implant overdenture is a popular treatment modality and is well documented in the literature. Follow-up studies with a long observation period are difficult to perform due to the increasing age of patients. The present data summarize a long-term clinical observation of patients with implant overdentures. MATERIALS AND METHODS: Between 1984 and 1997, edentulous patients were consecutively admitted for treatment with an implant overdenture. The dentures were connected to the implants by means of bars or ball anchors. Regular maintenance was provided with at least one or two scheduled visits per year. Recall attendance and reasons for dropout were analyzed based on the specific history of the patient. Denture maintenance service, relining, repair, and fabrication of new dentures were identified, and complications with the retention devices specified separately. RESULTS: In the time period from 1984 to 2008, 147 patients with a total of 314 implants had completed a follow-up period of >10 years. One hundred one patients were still available in 2008, while 46 patients were not reexamined for various reasons. Compliance was high, with a regular recall attendance of >90%. More than 80% of dentures remained in continuous service. Although major prosthetic maintenance was rather low in relation to the long observation period, visits to a dental hygienist and dentist resulted in an annual visit rate of 1.5 and 2.4, respectively. If new dentures became necessary, these were made in student courses, which increased the treatment time and number of appointments needed. Complications with the retention devices consisted mostly of the mounting of new female retainers, the repair of bars, and the changing of ball anchors. The average number of events and the rate of prosthetic service with ball anchors were significantly higher than those with bars. Twenty-two patients changed from ball anchors to bars; 9 patients switched from a clip bar to a rigid U-shaped bar. CONCLUSIONS: This long-term follow-up study demonstrates that implant overdentures are a favorable solution for edentulous patients with regular maintenance. In spite of specific circumstances in an aging population, it is possible to provide long-term care, resulting in a good prognosis and low risk for this treatment modality. For various reasons the dropout rate can be considerable in elderly patients and prosthetic service must be provided regularly.

Marginal Bone Level Changes and Prosthetic Maintenance of Mandibular Overdentures Supported by 2 Implants: A 5‐Year Randomized Clinical Trial

Documentation of early loading of mandibular overdentures supported by different implant systems is scarce. This study aimed to compare the biologic and prosthetic outcome of mandibular overdentures supported by unsplinted early-loaded one- and two-stage oral implants after 5 years of function. Twenty-eight consecutive patients were screened following an inclusion and exclusion criteria, and randomly allocated to treatment groups. Ball-retained mandibular overdentures were fabricated on two unsplinted Straumann (Institut Straumann AG, Basel, Switzerland) and Brånemark (Nobel Biocare AB, Göteborg, Sweden) dental implants and subjected to an early-loading protocol. During the 5-year period, prosthetic complications were recorded. At 5-years of function, plaque, peri-implant inflammation, bleeding, and calculus index scores were recorded, and standard periapical radiographs were obtained from each implant for measurement of marginal bone loss. All implants survived during the observation period. The peri-implant inflammation, bleeding, and calculus index scores around Straumann and Brånemark implants were similar (p > .05). The marginal bone loss around Brånemark implants (1.21 +/- 0.1) was higher than Straumann implants (0.73 +/- 0.06) at 5 years of function (p = .002). Kaplan-Meier tests revealed that 1- and 5-year survival of overdentures on Straumann and Brånemark implants were similar (p = .85). Wear of the ball abutment in the Brånemark group was higher than in the Straumann group (p < .05). Complications regarding the retainer and the need for occlusal adjustments were higher in the Straumann group (p < .05). Chi-square test revealed that the frequency of retightening of the retainer was higher in the Straumann group than in the Brånemark group (p < .05). Mandibular overdentures supported by unsplinted early-loaded Straumann and Brånemark implants lead to similar peri-implant soft tissue and prosthetic outcomes, although higher marginal bone loss could be observed around Brånemark implants after 5 years.

Within‐Subject Comparison of Two Rigid Bar Designs Connecting Two Interforaminal Implants: Patients' Satisfaction and Prosthetic Results

There is evidence for the superiority of two-implant overdentures over complete dentures in the mandible. Various anchorage devices were used to provide stability to overdentures. The aim of the present study was to compare two designs of a rigid bar connecting two mandibular implants. Completely edentulous patients received a new denture in the maxilla and an implant-supported overdenture in the mandible. They were randomly allocated to two groups (A or B) with regard to the bar design. A standard U-shaped bar (Dolder bar) was used connecting the two implants in a straight line. For comparison, precision attachments were soldered distal to the bar copings. Group A started the study with the standard bar (S-bar), while group B started with the attachment-bar (A-bar). After 3 months, they had to answer a questionnaire (visual analogue scale [VAS]); then the bar design was changed in both groups. After a period of another 3 months, the patients had to answer the same questions; then they had the choice to keep their preferred bar. Now the study period was extended to another year of observation, and the patients answered again the same questionnaire. In vivo force measurements were carried out with both bar types at the end of the test periods. The prosthetic maintenance service carried out during the 6-month period was recorded for both bar types in both groups. Statistical analysis as performed with the SPSS statistical package (SPSS Inc., Chicago, IL, USA). Satisfaction was high in both groups. Group B, who had entered the study with the attachment bar, gave slightly better ratings to this type for four items, while in group A, no differences were found. At the end of the 6-month comparison period, all but one patient wished to continue to wear the attachment bar. Prosthetic service was equal in groups A and B, but the total number of interventions is significantly higher in the attachment bar. Force patterns of maximum biting were similar in both bar designs, but exhibited significantly higher axial forces in the attachment bar. Both bar designs provide good retention and functional comfort. High stability appears to be an important factor for the patients' satisfaction and oral comfort. Rigid retention results in a higher force impact and appears to evoke the need for the retightening of occlusal screws, resulting in more maintenance service.

유한요소법을 이용한 하이브리드형 임플란트의 응력해석

Abstract After scientific verification of the osteointegration of dental implants, the overall efficiency of dental implants has been generally accepted. Thus, implants now play a major role in the clinical treatment of an edentulous mandible, and in the prosthetic maintenance equipment for partial edentulous mandible patients. Yet, for the successful long-term maintenance of implants, careful consideration of the bio-mechanics is needed to ensure that the maximum stress in the mandible as a result of chewing is maintained under a critical value. Accordingly, this study focuses on reducing the maximum stresses in an implanted mandible, especially in the cortical bone. Thus, the stresses in the implant and mandible are analyzed using finite element packages, including I-DEAS and NISA II/DISPLAY III, using a local zooming technique for a concentrated stress analysis. In addition, the von-Mises stress and principal stress in the mandible are both checked to determine the best combination.