Comparison between mainly mucosa-supported and combined mucosa-implant-supported mandibular overdentures

The purpose of this study is to compare mainly mucosa-supported and combined mucosa-implant-supported complete mandibular overdentures. Ten completely edentulous patients received 20 press-fit dental implants at the canine regions of the mandible. Each patient received 2 implants, which were left submerged and unloaded for 4 months. The patients were divided into 2 groups: group I patients received mandibular overdentures retained by a magnet attachment (mainly mucosa-supported overdenture). Group II patients received mandibular overdentures retained by a bar attachment (combined mucosa-implant-supported overdenture). The patients were evaluated clinically and radiographically immediately after overdenture delivery and after 6 months, 12 months, and 18 months. The results showed that the mainly mucosa-supported overdentures had less bone resorption distal to the implant in comparison to the combined mucosa-implant-supported overdentures. Plaque index score was significantly high in the group treated with magnet-retained overdentures. After 18 months follow up, the group treated with combined mucosa-implant-supported overdentures showed a significant increase in gingival inflammation when compared with the other group. The type of attachment or support may affect gingival inflammation or plaque accumulation. Increased functional load may affect bone density and resorption.     

Maxillary anterior and mandibular posterior residual ridge resorption in patients wearing a mandibular implant-retained overdenture

The mandibular implant-retained overdenture could improve masticatory function compared to the conventional complete denture. However, increased forces exerted by the overdenture could increase residual ridge resorption of the maxillary anterior and mandibular posterior areas. The aim of this study was to compare the effect of the mandibular implant-retained overdenture using two or four dental implants, or the conventional complete denture on resorption of the residual ridge of the maxillary anterior and mandibular posterior areas over a period of 10 years. In total, 120 patients, 30 patients treated with an overdenture on two implants (two-implant group), 30 patients with an overdenture on four implants (four-implant group) and 60 patients treated with a conventional full denture (conventional group), participated in this study. On panoramic radiographs, made before and 10 years after treatment, proportional area measurements were applied to determine changes in bone height. After 10 years, a statistically significant amount of bone resorption had occurred in the anterior maxilla in the two-implant group and in the four-implant group. A significant amount of bone resorption had occurred in the posterior mandible in all three groups. There were no statistically significant differences between the groups in both areas. Patients presented large individual differences. It is concluded that patients rehabilitated with implant-retained mandibular overdentures are not subjected to more residual ridge resorption in the anterior maxilla when compared to patients wearing a conventional full denture. Regarding the mandibular posterior residual ridge, resorption was irrespective of wearing an implant-retained mandibular overdenture or a conventional mandibular denture.     

种植体支持球帽附着体固位下颌覆盖全口义齿的临床应用

目的:评价种植体支持球帽附着体固位的下颌覆盖全口义齿临床应用效果.方法:随机选择15例下颌无牙颌患者,每例植入2枚种植体,共植入30枚,随访观察1-12个月,从患者满意度、临床检查及种植体X线片观察修复效果.结果:种植体支持覆盖全口义齿修复下颌无牙颌,义齿固位和咀嚼功能满意率分别为100％和93.3％,义齿稳固,咀嚼功...     

Posterior jaw bone resorption in osseointegrated implant-supported overdentures

For several years, osseointegrated implant-supported overdentures have been used in the rehabilitation of full edentulism with excellent results, at least in the lower jaw. This study involved 3 groups of patients with different prosthetic reconstructions: (1) mandibular overdentures supported by 2 implants connected by a bar (30 patients), (2) mandibular fixed prostheses supported by 4-6 implants (25 patients) and (3) mandibular complete dentures without implant support as controls (85 patients). The primary aim of this study was to examine on orthopantomograms (by means of the area index to minimize distortion and magnification errors), posterior mandibular ridge resorption in the 3 treatment groups. The present data demonstrated a minimal posterior mandibular ridge resorption in patients with fixed implant-supported prostheses. A more considerable posterior ridge resorption was observed in the complete denture group and especially in the overdenture wearers. For the latter, the annual posterior jaw bone resorption after the post-extraction remodeling period of 6 months, was 2- to 3-fold that of full denture wearers. When patients were edentulous for more than 10 years, the difference between the 2 latter groups disappeared. It is suggested that although the overdenture design on 2 implants offers advantages from a financial and failure rate point of view, its indications in younger patients should cautiously be evaluated in a long-term perspective concerning posterior mandibular bone resorption.     

The influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge. A 5‐year randomised clinical trial

This study aimed to compare the influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge after 5 years of denture wearing. Thirty edentulous male patients (mean age 62·5 years) received two implants in the anterior mandible after being allocated into two equal groups using balanced randomisation. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I, GI) or silicone resilient liners (group II, GII). The prosthetic and soft tissue complications of the maxillary dentures were recorded 6 months (T_6 m), 1 year (T1), 3 years (T3) and 5 years (T5) after overdenture insertion. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 5 years (T5) of overdenture insertion was calculated. Maxillary denture relining times and frequency of flabby anterior maxillary ridge occurred significantly more often in GI compared with GII. The change of R in anterior part of maxilla was significantly higher than change of R in posterior part in both groups. GI showed significant resorption of anterior residual ridge compared with GII. Relining times and frequencies of flabby ridge were significantly correlated with change in R. Within the limitations of this study, resilient liner attachments for bar‐implant‐retained mandibular overdentures are associated with decreased resorption and flabbiness of maxillary anterior residual ridge and fewer maxillary denture relining times when compared with clip attachments.     

An implant-supported overdenture in an edentulous upper jaw

An implant-supported overdenture is a good alternative treatment to a conventional denture for patients with complaints about the retention and stability of their removable complete denture. These complaints more often have to do with the mandibular than the maxillary denture. Implant-supported overdentures offer better results in the mandible than in the maxilla. In cases of insujficient bone volume in the maxilla for inserting implants, maxillary sinus floor elevation using an autogenous bone graft from the oral cavity or the iliac crest may be carried out. Treatment of the edentulous maxilla by inserting 6 implants followed by manufacturing a bar-clip mesostructure and an implant-supported overdenture is the most successful, followed closely by the treatment option of inserting 4 implants and fabricating a similar mesostructure and overdenture. Aftercare by routine preventive examinations is required.     

A randomized clinical trial comparing the efficacy of mandibular implant-supported overdentures and conventional dentures in diabetic patients. Part II. Comparisons of masticatory performance

Statement of problem. Convincing evidence is lacking to demonstrate the functional superiority of mandibular implant-supported overdentures over conventional dentures.Purpose. This randomized clinical trial was conducted to compare masticatory functional effectiveness of mandibular implant-supported overdentures and conventional dentures in diabetic denture wearers with clinically acceptable metabolic control.Methods. A total of 102 edentulous diabetic patients, treated with or without insulin, were randomized to receive a new maxillary and either a mandibular conventional denture or an implant-supported overdenture. Treatment was completed in 89 patients, 37 with conventional dentures and 52 with Hader bar-clip attachment overdentures supported by two IMZ implants. Besides data from medical and dental histories, oromaxillofacial examinations, and questionnaires, masticatory tests were performed by patients before and at 6 and 24 months after treatment completion. Although 78 patients (28 in the conventional, 50 in the overdenture group) performed tests at 6 months after treatment, 68 (25 in the conventional, 43 in the overdenture) had performance data for both entry and 6-month posttreatment intervals.Results. The two treatment groups were highly comparable in terms of general characteristics, quality of original dentures, tissue support, and past denture experience. No significant differences were found between patients treated for diabetes with or without insulin. All four masticatory performance scores with original dentures were higher in the conventional denture group than the overdenture group. The posttreatment performance scores for the two treatment groups became similar because of the higher gains in the overdenture group. Patients with low initial performance scores showed greater posttreatment gains with both conventional dentures and overdentures.Conclusions. The implant-supported overdenture showed no significant advantage over the conventional denture for improving the ability to comminute food in this group of diabetic patients with higher than average initial functional levels observed for other groups of denture wearers in previous studies. (J Prosthet Dent 1998;79:632-40.)     

Masticatory performance with mandibular implant-retained overdentures

It was investigated in a clinical trial whether the masticatory performance of complete-denture wearers depended on the support for their mandibular dentures by implants or mucosa. The trial involved the provision of a new maxillary denture and either a new conventional mandibular denture (mucosa-borne), a mandibular overdenture retained by two IMZ-implants (implant-mucosa-borne), or a mandibular overdenture on a transmandibular implant (TMI; mainly implant-borne). In comparison with mandibular implant-retained overdentures, subjects with conventional dentures needed 1.5 to 3.6 times more chewing strokes for an equivalent reduction in particle size. No differences in masticatory performance were found between subjects with IMZ-implants and those with TMI. This suggests that the increased stability of the mandibular denture with implants determines the wearer's masticatory performance, rather than the support by implants.     

球帽附着体种植覆盖全口义齿在下颌无牙领的应用

目的:了解球帽附着体种植覆盖义齿及脱钙人牙基质材料(DDM)在牙槽骨萎缩的下颌无牙颌的临床应用效果.方法:采用Frialit-2及Xive种植系统及骨又生-脱钙人牙基质材料(DDM)同期对17例牙槽骨萎缩的下颌无牙颌进行2枚种植体支持固位式球帽覆盖全口义齿修复.结果:经过1～2年的临床观察,种植体稳固,义齿功能优良,明显提高了患者的生活质量.结论:对严重萎缩牙槽嵴的下颌无牙颌患者,采用脱钙人牙基质材料(DDM)及种植覆盖总义齿进行修复,能有效地恢复功能,临床效果满意.     

下颌套筒冠固位全颌覆盖种植义齿即刻负重的临床研究

目的:探讨下颌无牙颌在种植后即刻进行套筒冠固位覆盖义齿修复技术的可行性和临床效果。方法:10例下颌无牙颌患者,术前常规行传统全口义齿修复,在双侧颏孔之间植入4颗种植体,术后当天即刻完成种植体支持的套筒冠固位覆盖义齿修复,均于负重后2、4、8、12、24、48周复诊,检查种植体的稳固性、种植体周龈组织状况,并拍摄X线片观察种植体骨吸收和骨结合状况。结果:10例患者共40颗种植体术后进行即刻负重,均获得良好的骨结合,临床检查种植体稳定性良好,种植体周龈组织健康,未见X线连续透射影,无边缘骨吸收,患者对修复效果满意。结论:下颌无牙颌患者,在双侧颏孔间植入4颗种植体,如种植体可获得足够的初期稳定性,即刻采用种植体支持的套筒冠固位覆盖义齿修复是可行的,短期临床效果满意。     

Evaluation of anterior maxillary alveolar ridge resorption when opposed by the transmandibular implant

Fifteen edentulous patients with complaints regarding denture comfort and/or function were treated with the transmandibular implant. All patients were restored with conventional maxillary dentures opposed by implant-supported removable prostheses. Two to 4 years after surgery, these patients were evaluated for vertical and horizontal maxillary bone loss with a radiographic analysis developed by the authors. With this technique, attention was focused on vertical alveolar ridge resorption in the anterior maxilla. Although the sample size was small, the findings from this study indicate that vertical bone loss in the anterior maxilla does occur when a maxillary denture is opposed by an implant-supported overdenture. Comparison of these results with a previous study that evaluated anterior maxillary resorption when a complete maxillary denture opposed natural mandibular anterior teeth and a distal extension removable partial denture demonstrated no statistically significant difference.     

Changes in the edentulous maxilla in persons wearing implant-retained mandibular overdentures

STATEMENT OF PROBLEM: It has been suggested that risk for severe resorption in the anterior maxilla is increased in persons wearing mandibular implant-retained overdentures. However, little information is available about the changes in the edentulous maxilla after mandibular implant treatment. PURPOSE: This study determined the possible changes in the width of the maxillary residual ridge 6 years after receiving mandibular implant-supported or implant-mucosa-supported overdentures and evaluated the association between the anatomic changes and subjective complaints with maxillary complete dentures. METHODS AND MATERIAL: The subjects for this study (n = 55), enrolled among the participants of a prospective clinical trial, were randomly assigned into 3 groups treated with: (a) implant-supported overdentures on a transmandibular implant system (n = 21); (b) implant-mucosa-supported overdentures on 2 IMZ implants (n = 20); or (c) conventional complete dentures (n = 14). A lingual contact occlusion concept with anterior open bite was used for tooth arrangement in all subjects. Diagnostic casts were made at baseline, and again at the 6-year follow-up. Most prominent points perpendicular to the crest of residual ridge were located in the incisor, canine, and premolar regions, after which the width of the ridge was recorded at these points with a Boley gage. Subjects' opinions on their dentures were evaluated with a questionnaire. RESULTS: Significant reduction in the width of the ridge was found in all measurement areas (mean difference = 0.4 to 0.6 mm; P <.0001). However, changes were small and not associated with the type of prosthetic restoration in the mandible. In subjects with implant-mucosa-supported overdentures, complaint of loose maxillary denture correlated with the decrement of residual ridge width. CONCLUSION: The width of residual ridge decreases with time, despite the type of mandibular prosthetic restoration.     

Clinical and radiographic evaluation of implant-retained mandibular overdentures with immediate loading

PURPOSE: The aim of this study was to evaluate and compare immediate-loaded implant-retained mandibular overdentures and delayed-loaded implant-retained mandibular overdentures. MATERIALS: Ten completely edentulous male patients received 40 dental implants. Patients were randomly divided into 2 equal groups, 5 patients each. Patients of both groups received conventional maxillary complete denture and had stage 1 surgery for placing 4 dental implant fixtures, 2 on each side anterior to the mental foramina. Group A: One-stage surgical procedure and immediate loading. Patients in this group received mandibular bar-retained overdenture supported by 4 endosseous implants loaded immediately after implant placement. Group B: The original 2-stage concept and delayed loading. Patients in this group received mandibular bar-retained overdenture supported by 4 endosseous implants that remained submerged for a period of 4 months before loading. The patients were evaluated clinically and radiographically immediately after overdenture delivery and after 6 months, 12 months, 18 months, and 24 months. RESULTS: The results of clinical evaluation showed no statistical significant difference between the 2 groups regarding the effect of treatment. The radiographic assessment showed no statistical significant difference in mesial and distal alveolar bone loss at the different intervals of the follow-up period, except at the 12-month period, where immediately loaded implants showed a decrease in the amount of alveolar bone loss mesially and distally compared to delayed loaded implants. CONCLUSIONS: The results suggest that immediate-loaded implants provide promising results compared to delayed-loaded implants and can be a possible alternative procedure in implant dentistry.     

Treatment planning: implant-supported partial overdentures

When multiple anterior teeth are missing, many options of replacement are available. Traditionally, the choice was between a fixed or removable prostheses. Today, with the predictability of dental implants, the options of tooth replacement range from removable partial dentures to implant-supported fixed prostheses. The choice of which restoration that will best provide occlusion and esthetics depends on multiple factors including the number and location of missing teeth, the residual ridge form in relation to the replacement teeth, the relationship of the maxillary and mandibular anterior teeth, the condition of teeth adjacent to the edentulous span, the amount of bone available for implant placement, the patients "smile line" and display of teeth, lip support, and financial constraints. When there is minimal loss of the ridge contour, restorations that emerge from the ridge are the most functional and esthetic restorations, adhesive-type fixed partial dentures, conventional fixed partial dentures, and implant-supported restorations can be indicated with the choice of restoration dependent on a risk benefit and cost benefit analysis. When there is a loss of ridge contour due to residual ridge resorption or trauma, the decision becomes more complex as not only does the tooth structure need to be replaced, the ridge form also has to be replaced. (Figures 1 and 2). This can be assessed clinically as illustrated by Figures 1 and 2 where a dis crepancy in arch form and ridge form in relation to the adjacent teeth and/or opposing arch can be observed. Other considerations are lip support and display of the teeth when smiling. This article presents a case and rationale for implant-supported par tial overdentures. Many authors have written on the merits of com plete overdentures. The complete overdenture has proven to be an improvement over conventional complete prostheses with respect to chewing efficiency, patient comfort and satisfaction. In partial edentulism, the implant-supported overdenture has several advantages, some in common with a removable partial denture.     

Attachment of clips in a bar-retained maxillary implant overdenture: a clinical report

Implant-supported overdentures are a good alternative for patients with conventional dentures that lack retention and stability. The most common prosthetic complications in mandibular and maxillary implant-supported overdentures are fracture and loosening of the attachment system. This clinical report describes the treatment of a completely edentulous patient with sinus floor elevation by using bone from the iliac crest and the insertion of 4 implants in the maxilla and mandible followed by implant-supported overdentures. The technical procedure for the attachment of clips to an acrylic resin overdenture base with the use of metal reinforcement is described. The advantage of this attachment procedure is an improved attachment system with less fracture and less loosening of the clips.     

Comparing the efficacy of mandibular implant-retained overdentures and conventional dentures among middle-aged edentulous patients: satisfaction and functional assessment

PURPOSE: The aim of this randomized clinical trial was to compare the relative efficacy of mandibular overdentures retained by only two implants and a bar attachment with conventional dentures. MATERIALS AND METHODS: Edentulous adults, aged 35 to 65 years, were randomly assigned to two groups that received either a mandibular conventional denture (n = 48) or an overdenture supported by two endosseous implants with a connecting bar (n = 54). All subjects rated their general satisfaction and other features of their original dentures and their new prostheses (comfort, stability, ability to chew, speech, esthetics, and cleaning ability) on 100-mm visual analogue scales prior to treatment and 2 months postdelivery. Oral health-related quality of life was also evaluated pre- and posttreatment. RESULTS: Multiple regression analysis revealed that the mean general satisfaction was significantly higher in the overdenture group than in the conventional denture group (P = .0001). Age, gender, marital status, and income were not significantly associated with ratings of general satisfaction. Furthermore, the implant group gave significantly higher ratings on three additional measures of the prostheses (comfort, stability, and ease of chewing; P < .05). CONCLUSION: A mandibular two-implant overdenture opposed by a maxillary conventional denture is a more satisfactory treatment than conventional dentures for edentulous middle-aged adults.     

Does a prosthodontist spend more time providing mandibular two-implant overdentures than conventional dentures?

PURPOSE: In this article, the time taken by a prosthodontist to fabricate and maintain mandibular overdentures retained by two implants and conventional dentures is compared. MATERIALS AND METHODS: Sixty edentulous patients between the ages of 65 and 75 completed a randomized clinical trial. All received new maxillary conventional dentures and either a mandibular conventional denture (n = 30) or a two-implant overdenture on ball attachments (n = 30). The time spent by the prosthodontist and the number of visits required for treatment, including both scheduled and unscheduled visits, were recorded for each patient from preliminary impressions to 6 months following delivery. Data from the two groups were compared using Mann-Whitney U tests. RESULTS: The prosthodontist spent a mean total time of 296 minutes in treating an implant overdenture patient and 282 minutes on a conventional denture patient during the period from preliminary impressions to the 6-month follow-up. The mean numbers of appointments were 10.1 (implant group) and 10.8 (conventional group). These differences were not significant. CONCLUSION: Although additional knowledge is required to treat patients with implant prostheses, the time required by the prosthodontist to provide two-implant mandibular overdentures with ball attachments was not significantly different than the time needed for conventional denture treatment.     

Patient satisfaction and dissatisfaction with mandibular two-implant overdentures using different attachment systems: 5-year outcomes

BACKGROUND: Different attachment systems for mandibular two-implant overdentures could influence levels of patient satisfaction. Positive consensus of the majority of patients being satisfied does not preclude the possibility of dissatisfaction for some. PURPOSE: To evaluate patient satisfaction before and after 5 years of wearing mandibular two-implant overdentures using different attachment systems. MATERIALS AND METHODS: A total of 106 edentulous participants enrolled in a clinical trial completed a preliminary self-report inventory of their original complete denture complaints. New complete maxillary dentures and mandibular two-implant overdentures were provided to each participant using one of six different attachment systems. Patient satisfaction was determined at pretreatment; at baseline with mandibular two-implant overdenture insertion; and then annually for 5 years, using visual analogue and Likert-type scales. ReSULTS: Patient satisfaction with mandibular two-implant overdentures at baseline was significantly improved in all domains compared to pretreatment (old dentures) and sustained up to the 5-year recall. The level of satisfaction with Straumann gold alloy matrices at 5 years was significantly lower than that with other attachment systems. Highly significant differences were found with some social and psychological aspects by the fifth year compared to baseline. Diagnostic and prognostic indicators from a pretreatment inventory identified 12 participants (13.5%) who were dissatisfied. These indicators revealed a maladaptive predisposition to mandibular two-implant overdentures. ConclusIONS: A mandibular two-implant overdenture (opposing a conventional complete maxillary denture) will improve patient satisfaction, regardless of the attachment system. Careful evaluation of pretreatment complaints with conventional dentures can possibly identify patient dissatisfaction with mandibular two-implant overdentures.     

locator种植覆盖义齿在下颌无牙颌修复中的应用

目的：探讨locator附着体种植覆盖义齿在下颌无牙颌修复中的临床应用效果。方法：对12例下颌无牙颌患者,每名患者下颌植入2枚种植体,共24枚,3~4个月后完成locator附着体覆盖义齿修复。术后2年期间进行随访。结果：24枚种植体均无松动,骨无明显吸收,患者对义齿咀嚼及固位满意。结论：locator附着体固位的种植覆盖义齿是下颌无牙颌患者理想的修复方式。     

A cost comparison of mandibular two-implant overdenture and conventional denture treatment

PURPOSE: This article compares the cost of mandibular two-implant overdenture treatment to that of conventional denture treatment in an academic teaching hospital. MATERIALS AND METHODS: Sixty edentulous patients (aged 65 to 75 years) participated in a randomized clinical trial. All patients received a new maxillary complete denture and either a mandibular conventional denture (n = 30) or an implant overdenture on two unsplinted implants (n = 30). Resource-based microcosting of direct and indirect costs (eg, expenses and time cost to patients) of all scheduled and unscheduled visits was conducted through 1 year following delivery of the prostheses. RESULTS: Mean direct costs (1999 CD dollars) for scheduled visits in the implant and conventional groups were 2,332 dollars and 814 dollars, respectively, and mean indirect costs were 1,150 dollars and 810 dollars, respectively. Differences between the two groups were significant. Twenty-six patients in each group had unscheduled visits during the study at a median direct cost for the overdentures of 85 dollars and 64 dollars for the conventional dentures. Median indirect costs for unscheduled visits were 163 dollars and 202 dollars, respectively. These differences were not significant. Mean total costs of the overdentures were 4,245 dollars and 2,316 dollars for the conventional dentures, and the between-group difference was significant. CONCLUSION: The direct cost of mandibular two-implant overdenture treatment was 2.4 times higher than that of conventional denture treatment. When indirect costs were added, the implant-to-conventional total cost ratio estimate was 1.8. These cost data can now be combined with estimates of the efficacy of the two types of prosthesis so practitioners and patients can make informed decisions about these prosthodontic treatment concepts.