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Pain and instability during biting with mandibular implant-retained overdentures.

We tested in a randomized controlled clinical trial the effect of pain and instability of dentures on bite force with different degrees of mucosal support. The trial involved 3 groups who had received: 1) a new conventional denture (CD-group), 2) an implant-mucosa-borne overdenture on 2 IMZ implants (IMZ-group) or 3) a mainly implant-borne overdenture retained by a transmandibular implant (TMI-group). Fifty-three women and 15 men, mean age 59 years, participated in this study. Bite force measurements were made unilaterally with a transducer and bilaterally with a bite fork. After the measurements, subjects were asked whether or not biting had caused pain or tilting of one of the dentures. Significantly more complete-denture wearers reported pain. They reported more frequent pain in the mandible than in the maxilla (P < 0.001), whereas implant-groups seemed to experience more often pain in the maxilla. On the transducer, maxillary dentures of the CD-group tilted less (P < 0.01) and mandibular dentures more (P < 0.05) compared to the implant-groups. With the bite fork, tilting occurred more often in the incisal-cuspid area than in the molar region (P < 0.001). No effect of pain and tilting was observed on maximum bite force. It appears that oral implants used to stabilize mandibular dentures permit subjects to exert higher bite forces and reduce the pain as otherwise felt in the mandible during maximum biting. Due to this stabilization, pain and instability of the maxillary denture can become the limiting factor for a further increase in bite force.

Adult↗

Satisfaction and psychosocial aspects of patients with an extremely resorbed mandible treated with implant-retained overdentures. A prospective, comparative study.

The objective of the present report was to study the effect of implant treatment on subjective parameters in edentulous patients with an extremely resorbed mandible. Three different treatment modalities to support an overdenture were compared: transmandibular implant according to Bosker, augmentation of the mandible followed by four endosseous implants, and the insertion of four short endosseous implants. Sixty patients [50 women and 10 men, mean (+/- SD) age 59 (+/- 11) years] met the inclusion criteria and were assigned in one of the three treatment groups. Before treatment and 12 months after placement of the new overdentures, denture satisfaction, psychosocial aspects and experiences during the surgical phase were assessed with a battery of questionnaires. After 1 year, 58 patients were available for evaluation: one patient had died, and one patient had moved out of the region. There was a significant improvement of patient satisfaction and psychosocial functioning in all three treatment groups. At the 1-year evaluation, differences amongst the three groups were not significant. However, in terms of discomfort and pain during the surgical phase as well as the length of this phase (at least 6 months), the augmentation using an autologous bone graft from the iliac crest followed by inserting four endosseous implants 3 months later appeared the least favorite option of the three modalities studied.

Alveolar Ridge Augmentation↗

Marginal bone loss around implants retaining hinging mandibular overdentures, at 4-, 8- and 12-years follow-up.

AIM: The aim of the present study was to study the effect of occlusal factors, oral hygiene, gender and age on the long-term maintenance of alveolar bone height around screw-shaped machined surface commercially pure (c.p.) titanium implants retaining hinging mandibular overdentures. METHOD: In this retrospective study a long-term (4-, 8-, up to 12-years) follow-up of such implant-retained overdentures was performed. From the population of patients so treated at the University Hospital of the Catholic University Leuven, Department of Periodontology and Department of Prosthetic Dentistry, 158 patients were selected on the basis of being treated before March 1994, and the availability of intra-oral radiographs (paralleling technique) present at abutment connection (baseline) and at years 4, 8, and 12. For each patient, all relevant clinical data were recorded, and measurements of marginal bone height around the implants were performed on intra-oral radiographs by means of a digital sliding caliper. RESULTS: Results indicated that only the factor "time" had a significant influence on marginal bone loss. The age and gender of the patients, dental/prosthetic status in the antagonistic jaw, oral hygiene variables, and location of the implants had no significant effect. CONCLUSION: The very high cumulative success rate (97.2%) and limited marginal bone loss (on average 1.7 mm) after 12-years, encourage this kind of treatment using this type of implants.

Adult↗

Preparation of guide planes using a reciprocating handpiece.

A reciprocating handpiece and attachments have been found effective in preparing guide planes prior to the construction of removable partial dentures. A comparison was made of the enamel surface prepared using the reciprocating handpiece and a conventional rotary handpiece. Two-stage and three-stage techniques for each handpiece were compared. Scanning electron micrographs showed that a smoother surface was created by the reciprocating handpiece.

Bicuspid↗

Implant anchored complete mandibular denture: evaluation of masticatory efficiency, oral function and degree of satisfaction.

Masticatory efficiency, oral function and degree of satisfaction with the treatment received were analysed in a group of fully edentulous patients with severe atrophy of the mandibular bone, rehabilitated with complete removable dentures, before and after anchoring the dentures to osseointegrated implants. Masticatory efficiency increased significantly and chewing cycles increased in amplitude after anchoring the denture. The component of the chewing cycle that most influenced the increase in functional area was the lateral one. A correlation was found between the increase in the lateral component of the chewing cycle and the increased masticatory efficiency achieved with implant-anchored dentures. The degree of satisfaction with their rehabilitation reported by the subjects was correlated neither to increased masticatory efficiency nor to improved oral function.

Aged↗

Masticatory performance and chewing experience with implant-retained mandibular overdentures.

The relationship between masticatory performance and chewing experience has not yet been explored for patients with implant-retained overdentures. Although many relationships have been found between parameters of objective and subjective oral function, the structure of these relationships remain unclear. Therefore, we studied in a randomized clinical trial the relationship between the comminution of an artificial test food, i.e. masticatory performance, and the subjective chewing experience. The trial involved a comparison between two groups receiving implant treatment and one group receiving conventional complete dentures (CD). The implant treatment involved either a mainly implant-supported mandibular overdenture on a transmandibular implant (TMI) or an implant-tissue-supported mandibular overdenture on two IMZ implants (IMZ). Masticatory performance as well as chewing experience were substantially better for the implant-retained overdentures compared with the complete denture group. No significant differences emerged between the TMI and the IMZ group. A multiple regression analysis did not provide any comprehensibility in the relationship between masticatory performance and the variables of chewing experience. In the linear structural relation analysis (LISREL) no direct relationship was found between masticatory performance and functional complaints mandibular denture. The results show that an improvement in masticatory performance does not imply the same improvement in chewing experience and vice versa.

Adult↗

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.

Aged↗

A simple prosthetic approach using cement-retained implant prosthesis after surgical treatment of ameloblastoma.

Ameloblastoma is an odontogenic tumor of epithelial origin that manifests itself in the maxillofacial area with marked deformity. After removal of the tumor, prosthetic reconstruction may be challenging because of extensive tissue loss, which necessitates careful treatment planning. We describe a case in which a patient lost considerable supporting tissue after excision of the tumor. The mandible was grafted with autogenous corticocancellous bone harvested from the left anterior iliac crest in a delayed manner. After healing, six implants were placed. After second-stage surgery, a new method was used to reduce thickness of the soft tissue around the implants. A cement-retained nine-unit fixed partial denture was fabricated in three clinical visits. The patient has been monitored for 5 years with no complications despite the use of cement to retain the prosthesis and the unfavorable crown-to-root ratio.

Ameloblastoma↗

Swallowing thresholds of mandibular implant-retained overdentures with variable portion sizes.

We analysed the effect of three portion sizes Optocal Plus (small, medium and large) on swallowing thresholds in subjects with either conventional complete dentures or mandibular implant-retained overdentures (transmandibular and permucosal cylindric implants). Tests were carried out in 52 women and 15 men (mean age 59 years) 4 years after treatment in a randomised controlled clinical trial. The results indicated that the degree of mucosal support for the mandibular denture did not affect the number of chewing strokes, time till swallowing or swallowed particle size. Only the chewing rate differed: subjects wearing mandibular implant-retained overdentures chewed the food at a higher rate than complete-denture wearers. With larger portion sizes, subjects needed significantly more chewing strokes and time until swallowing and they would have swallowed larger particles. Men chewed their food more efficiently than women, as they used the same number of chewing strokes and time, but achieved a greater particle size reduction at the swallowing moment.

Adult↗

Mandibular two-implant telescopic overdentures.

To stabilize mandibular overdentures in edentulous patients, various connector types which can be attached to between two and four implants placed in the anterior mandible are possible. Treatment using non-rigid telescopic connectors on two interforaminal implants for overdenture stabilization began in 1989. The objective of this study is to investigate soft- and hard-tissue conditions as well as prosthesis function after a period of 10 years. This also involved an evaluation of correlations between radiographic and clinical parameters. Twenty-three subjects with 46 interforaminal implants (ITI solid screw implants, 12 mm in length, 4.1 mm in diameter; 10.4 years in situ, range, 8-12.8 years) were investigated. Modified plaque index (mPI), sulcus fluid flow rate (SFFR), modified sulcus bleeding index (mBI), probing depth (PD), distance from implant crown margin to the coronal border of the peri-implant mucosa (DIM), attachment level (AL), width of keratinized mucosa (KM), Periotest values (PTVs) and prosthesis function were evaluated. In the radiographic evaluation, the distance between implant shoulder and first crestal bone-implant contact (DIB) in mm and the horizontal bone loss (HBL) in mm were measured. The relatively high mPI scores (mean, 0.82; score, 0 in 44.4%; SD, 0.83) did not result in increased SFFR scores (mean, 12; min, 3, max, 38; SD, 7.43) or higher mBI scores (mean, 0.35; score, 0 in 70.8%; SD, 0.59), which was commensurate with healthy peri-implant mucosa. A mean PD value of 2.15 mm (min, 1 mm; max, 5 mm; SD, 0.96) and a mean DIM value of 0.28 mm (min, 0 mm; max, 2 mm; SD, 0.52) were measured. The implants were stable, showing a mean Periotest value of -1.91 (max, 02, min, -6; SD, 1.76). A mean DIB of 3.19+/-0.95 mm (range, 1.3-5.16 mm) and a mean HBL of 1.6+/-1.52 mm (range, 0.28-8.33 mm) were calculated. A correlation was found between DIB and the parameters SFFR (P=0.060), DIM (P=0.042), AL (P=0.050) and especially PTV (P<0.01), leading to the assumption that these clinical parameters may be useful indicators of peri-implant bone loss. The results of the 10-year follow-up examination show that non-rigid telescopic connectors with two interforaminal implants for overdenture stabilization appear to be an efficient and effective long-term treatment modality in severely resorbed edentulous mandibles. Particularly in geriatric patient treatment this concept may provide advantages in terms of handling, cleaning and long-term satisfaction.

Aged↗

Loading of bone surrounding implants through three-unit fixed partial denture fixation: a finite-element analysis based on in vitro and in vivo strain measurements.

Implant-borne fixed partial dentures (FPDs), whether cementable or screwable superstructures, ought to display a true passive fit. The objective of this in vivo-based finite-element analysis is, therefore, to quantify the degree of stress which occurs in the bone around the implants as a result of the fixation of cemented and screw-retained FPDs. On the basis of a simulated patient situation with two implants, six groups of implant-supported superstructures containing 10 samples each were fabricated. Strain gauges which were mounted on the pontics of the restorations were subsequently used to take in vivo measurements (Ethics Commission Approval No. 2315). Taking the values obtained as a basis, the von Mises equivalent stress was chosen to illustrate bone loading in three-dimensional finite-element models. Superstructure fixation caused residual interface stress as high as 30 MPa. Similar stress magnitudes can be observed for axial implant loading of 200 N. Assuming that the axial loading of a single implant with 200 N is within the bone's physiological range, it can be concluded that the degree of stress resulting from the fixation of superstructures alone does not constitute a risk.

Cementation↗

Clinical and radiological results of patients treated with two loading protocols for mandibular overdentures on Brånemark implants.

OBJECTIVE: The aim of this study was to evaluate clinical and radiological outcomes of the unsplinted implants supporting mandibular overdenture when applying conventional or early loading protocols. MATERIAL AND METHODS: Twenty-six edentulous patients were treated with two unsplinted Brånemark System implants supporting mandibular overdenture. There was a test group, in which the overdenture was connected 1 week after surgery, and a control group, in which the overdenture was connected 3 months after surgery. Peri-implant parameters were recorded 1, 6, and 12 months after surgery. Clinical stability measurements were performed at surgery, and after 3, 6, and 12 months. Marginal bone levels were evaluated at implant surgery, after 6, and after 12 months. RESULTS: No implant from either group was lost. Clinical peri-implant parameters, clinical stability measurements, and marginal bone resorptions showed no statistically significant differences between two groups during 12 months. CONCLUSION: The results of this study suggest that one-week of early loading protocol of two Brånemark implants supporting mandibular overdenture does not compromise implant stability, marginal bone loss, and peri-implant soft-tissue health.

Aged↗

The milled bar-retained removable bridge implant-supported prosthesis: a treatment alternative for the edentulous maxilla.

Restoration of the edentulous jaw with dental implants can be achieved using either an implant-supported prosthesis, such as a fixed bridge, or an implant-retained prosthesis, such as a traditional overdenture. The implant-retained prostheses use edentulous ridges as primary stress-bearing regions, and through stress-breaking mechanisms, the implants are not loaded during function. However, the success rates of maxillary overdentures do not appear to be as good as for mandibular overdentures; this may be attributable to the adverse loading conditions, short implant length, poor quality of bone, number of implants used, flexible bar design, or poor treatment planning. Many articles have also described the numerous problems and multiple visits required in maintaining a traditional bar-retained overdenture restoration, often making it more expensive in the long term than a fixed restoration. The milled bar implant-supported prosthesis offers the benefits of both fixed and removable restorations. Its infrastructure provides the same rigidity as the fixed restoration, owing to the precise fit to the superstructure, which is removable, to promote adequate access for hygiene, yet it still provides lip support and maintains close contact with the soft tissues. These advantages enhance phonetics, esthetics, correct lip support, maintenance, and patient comfort.

Adult↗

Implant-supported denture in a patient with Huntington's disease: interdisciplinary aspects.

Patients with extrapyramidal diseases often cannot maintain independent, efficient oral hygiene due to restricted motor ability of the upper extremities and lack of coordination. The hermetic closure of the mouth and lips, and the associated ability to keep liquid and toothpaste in the mouth, can become so weak that effective oral hygiene cannot be maintained. Over a period of many years, this illness leads to loss of teeth and the need for complete prosthodontic care. Dyskinesia and hyperkinesia of the tongue and the peri-oral musculature, combined with xerostomia and pooling of saliva, make it impossible for the patient to wear a conventional complete denture, despite an anatomically-adequate bearing area. In such cases, an implant-supported prosthesis is a better therapeutic measure, although some aspects of oral hygiene must initially be disregarded. Two ITI implants were inserted into the anterior mandibular region of a patient with Huntington's chorea, because a complete denture could not be retained on the alveolar ridge, despite adequate vestibule depth, due to tongue dyskinesia. A bar joint was used to anchor this mucosal-borne denture. This implant-supported complete denture led to a clear improvement in the patient's chewing function when observed over a period of a year.

Anesthesia, Dental↗

A within-subject comparison of mandibular long-bar and hybrid implant-supported prostheses: evaluation of masticatory function.

Sixteen edentulous subjects participated in a within-subject crossover clinical trial to test the hypotheses that a long-bar overdenture attached to 4 implants gives greater patient satisfaction and masticatory efficiency than a two-implant hybrid overdenture. All subjects were given a new maxillary conventional denture. Ten received mandibular long-bar overdentures first and six the hybrid overdentures. Two months later, psychometric assessments and functional tests were repeated 3 times at one-week intervals. The mandibular prosthesis was then changed, and recordings were repeated after another 2 months. Mandibular movements and electromyographic activity of jaw muscles were recorded while subjects chewed standard-sized pieces of 5 foods: bread, cheese, apple, sausage, and carrot. Measurements included masticatory time, cleaning time (the time between the end of mastication and the last swallow), and duration and amplitude of masticatory cycles and phases. Multilevel analyses were performed. No significant differences in masticatory time were found between prostheses for any test food. However, cleaning time for carrot [estimated mean of difference (delta) +/- SE: 1.6 sec +/- 0.7] and bread (delta = 1.0 sec +/- 0.4) was slightly but significantly longer for subjects wearing long-bar overdentures. Cycle duration was longer with the long-bar overdenture only for subjects chewing carrot. The opening phase was shorter and the closing phase longer with the long-bar overdenture for almost all test foods. Vertical amplitude was significantly less with the long-bar overdenture for cheese (delta = -2.6 mm +/- 1.1), apple (delta = -2.6 mm +/- 1.0), and sausage (delta = -2.9 mm +/- 1.3). These results suggest that mastication with the 2 prostheses is equally efficient, although clearance of some foods from the mouth is longer with the long-bar overdentures. They also indicate that patients adapt their masticatory movements to the characteristics of different prostheses.

Adult↗