Effect of implant support for prostheses on electromyographic activity of masseter muscle and jaw movement in patients after mandibular fibula free flap reconstruction.

PURPOSE: Dental implants are used to stabilize, support, and retain prostheses in the mandible following fibula free flap reconstruction. A previous longitudinal prospective study showed that an implant-supported prosthesis (IP) provided additional improvement in masticatory performance compared to a conventional prosthesis (CP). Therefore, in this paper, the impact of implant retention and support of mandibular prostheses on neuromuscular function is reported via a within-subject analysis. MATERIALS AND METHODS: Forty-six participants were enrolled in the study. Prosthetic treatment with a CP was completed in 33 subjects following oromandibular resection and fibula free flap reconstruction. Twenty-five subjects completed evaluation of the CP after an adaptation period. Standardized masticatory tests with peanuts were given to subjects on the defect and nondefect chewing sides. Electromyography (EMG) of masseter muscles and jaw movement was performed and recorded simultaneously in 19 of these subjects. IP treatment was then completed in 16 of these subjects, and 15 of them participated in the IP evaluation after an adaptation period. Of these 15 subjects, 13 completed EMG and jaw movement recordings for both CP and IP. RESULTS: EMG activity of the defect-side masseter muscle increased significantly from CP to IP conditions when chewing on either side, but no significant change was found for nondefect-side muscle activity. Jaw movement parameters showed no significant changes from CP to IP. CONCLUSION: In patients restored with mandibular fibula free flap reconstruction, implant support for mandibular prostheses has the benefit of permitting greater muscle effort on the defect side, irrespective of the side on which the bolus is being chewed. The impact of an IP on jaw movements is limited.

Mandibular fracture in conjunction with bicortical penetration, using wide-diameter endosseous dental implants.

Prosthodontic rehabilitation of a patient with an atrophic edentulous mandible presents a significant challenge in restoring esthetics and function. The purpose of this clinical report is to describe fracture of an atrophic edentulous mandible opposing maxillary natural dentition in association with endosseous dental implants. The patient received two wide-diameter implants in the anterior mandible for an implant-assisted mandibular overdenture, in which the implants penetrated the inferior border of the mandible for bicortical stabilization. Three months following implant placement surgery, the patient experienced pain, swelling, and intraoral purulent drainage around the right implant. Panoramic radiograph revealed a fracture of the mandible through the right implant site and signs of infection around the left implant. The implants were removed surgically, and open reduction and fixation of the fracture site were undertaken using a titanium bone fixation plate. This clinical report demonstrates that placement of wide-diameter implants in conjunction with bicortical penetration in a severely atrophic edentulous mandible can risk fracture of the mandible.

The frequency of replacement of dental restorations may vary based on a number of variables, including type of material, size of the restoration, and caries risk of the patient.

SUBJECTS: The authors analyzed the dental records of 2780 Navy (cohort 1 = 1078 entered the Navy in 1997) and US Marine Corps recruits (cohort 2 =1053 entered the USMC in 1999-2000; cohort 3 = 649 entered the USMC in 2002-2005). The records were reviewed at 16 US Navy dental treatment facilities at the following time periods: cohort 1, 2001; cohort 2, 2002-2003; and cohort 3, 2005-2006. The mean age of the subjects was 20 years, and 85% were men. Only posterior teeth (not third molars) with amalgam or resin-based composite (including glass ionomer restorations) were evaluated. Teeth that had been restored with more than one material and restorations that did not involve the occlusal surface were excluded. The minimum follow-up time was 2 years with at least 2 periodic exams following the initial exam. KEY EXPOSURE/STUDY FACTOR: The primary factor of interest was the type of restorative material (amalgam versus resin-based composite). Secondary factors included tooth number, number of restored surfaces (single or multiple), and caries risk of the patient. Caries risk status was defined using the Navy Dental Corps Oral Disease Risk Management protocol. MAIN OUTCOME MEASURE: The primary outcome measure of interest was the determination of the relative risk of replacement of an initially intact restoration during the subject's first years of military service. Restorations were classified as clinically acceptable or requiring replacement either as a result of new primary caries, secondary caries, defective restorations, or endodontic therapy. MAIN RESULTS: At the initial exam, 964 (15.2%) of the amalgam restorations and 199 (17.4%) of the resin-based composites required replacement and were excluded from further analysis. Of the remaining restorations, an additional 14.2% of the amalgam and 16.7% of the composite restorations required replacement during the observation period. The mean follow-up time was 3.0 years (cohort 1, 3.4 years; cohort 2, 3.1 years; cohort 3, 2.3 years). Replacement rates for resin-based composite restorations compared with amalgam were significantly higher owing to all causes (adjusted hazard ratio [HR], 1.28; P < .05) and for replacement owing to restoration failure (adjusted HR, 1.64; P < .01). Multiple surface restorations demonstrated higher rates of replacement than single surface restorations from all causes (adjusted HR, 1.39; P < .01) and for replacement of existing restorations (adjusted HR, 1.82; P < .01). High-caries-risk subjects experienced more than twice the risk of retreatment than did low-caries-risk subjects when considering all replacements (adjusted HR, 2.04; P < .01) and 50% higher risk of replacement of previously restored surfaces (adjusted HR, 1.48; P<.01) CONCLUSIONS: Approximately 30% of all posterior restorations required replacement either at the initial or subsequent exams during the observation period. The number of resin-based composite restorations requiring replacement was significantly higher than amalgam restorations. The authors concluded that because of the extra cost, time, and potential for increased frequency of replacement, posterior composite restorations should be limited to restorations of appropriate size and placed under meticulous restorative technique with strict adherence to manufacturer's instructions.

The social solution-denture esthetics, phonetics, and function.

Tooth loss and rehabilitation with dentures can have tremendous patient impact and social implications. In an image-conscious society, dentures restore a sense of normalcy and allow the patient the ability to interact with others. The most frequent denture complaints include chewing discomfort and objectionable esthetics and phonetics. Determining patient expectations and their influence on patient satisfaction with treatment is critical. Current evidence on functional outcomes, patient satisfaction, and cost-effectiveness of treatment with conventional dentures versus implants are important factors to consider during treatment planning for the edentulous patient. The purpose of this article is to review some exemplar literature for the successful treatment of the edentulous patient.

Optimization of maxillary obturator thickness using a double-processing technique.

Preservation of remaining structures is a primary goal of prosthetic rehabilitation. Continuously applied stresses on the remaining tissues from a large, heavy obturator jeopardize the health of the tissues, compromise the function of the prosthesis, and affect patient comfort. Various techniques have been described for hollowing the bulb of an obturator after processing to reduce its weight; however, access to the inner aspects of the bulb is limited, preventing adequate control of thickness of the walls. This article describes a double-processing technique for an obturator to optimize the weight and thickness of the bulb.

Use of osseointegrated implants in the restoration of head and neck defects.

Osseointegrated implants can be applied to facilitate retention, stability, and support for facial and intraoral prostheses used to restore head and neck defects. At the University of California, Los Angeles, Maxillofacial Prosthetics Clinic, retrospective studies have indicated that in nonirradiated maxillectomy patients, implant survival rates are 82.6 percent. In mandibles reconstructed with fibula free flaps, survival rates are 94.6 percent. Similarly, high implant survival rates have been observed for most sites used to support facial prostheses. Cumulative six-year survival rates for auricular sites exceed 95 percent and for floor of nose sites, success rates exceed 87 percent. However, survival rates are low (53 percent) for implants placed in the frontal bone for retention of orbital prostheses and even lower for irradiated bone sites ranging from 63 percent in the maxilla to 27 percent in the orbit.

Masticatory and swallowing threshold performances with conventional and implant-supported prostheses after mandibular fibula free-flap reconstruction.

STATEMENT OF PROBLEM: Significant strides in microvascular surgical techniques allow predictable restoration of bony and soft tissue orofacial defects. In combination with prosthetic rehabilitation, varying degrees of improvement in esthetics, speech intelligibility, and swallowing have been noted; however, the relative impact of conventional and implant-supported prostheses on restoration of masticatory function are not known. PURPOSE: The purpose of this study was to determine whether conventional or implant-supported dental prostheses and current surgical reconstructive procedures restore patients' masticatory function to presurgical levels. MATERIAL AND METHODS: Of the 46 subjects enrolled in this study, 23 (7 edentulous and 16 partially dentate) completed conventional prosthesis (CP) treatment and masticatory evaluation, and of these, 15 (3 edentulous and 12 partially dentate) completed treatment and evaluation with an implant-supported prosthesis (IP). Standardized masticatory performance tests with peanuts and carrots as the test food were made on the defect and nondefect sides. Tests of swallowing threshold performance were made with carrots as the test food. Statistical analysis included repeated-measures analysis of variance (ANOVA) with post hoc Tukey HSD tests (alpha=.05). RESULTS: Masticatory function at entry was markedly compromised. Further performance declines were noted following surgery (PS) on both the defect and nondefect sides. Restoration with CP and IP produced improvements (significant for defect side only, P<.05) in performance over the PS interval and were not significantly different from performances at entry prior to surgery. In addition, the performance on the defect side with the IP was significantly greater than the performance with the CP (P<.001). CONCLUSION: Impairment in masticatory ability remains following free-flap reconstruction prior to prosthetic rehabilitation. Both CP and IP may provide improved masticatory ability, permitting patients to regain the functional level they possessed prior to surgical intervention. The IP may contribute to greater support and stability of the prosthesis, resulting in increased use for mastication and superior performance on the defect side compared to the CP.

Efficacy of conventional and implant-supported mandibular resection prostheses: study overview and treatment outcomes.

STATEMENT OF PROBLEM: While surgical restoration of mandibular resections has advanced dramatically with free-flap techniques, oral function and patient perceptions of function, as well as treatment outcomes, often indicate significant impairment. PURPOSE: This longitudinal prospective study was designed to determine whether conventional prostheses (CP) or implant-supported prostheses (IP) and current surgical reconstructive procedures restore patients' oral functions and quality of life to their status prior to segmental mandibulectomy with immediate fibula free-flap reconstruction. Study design and implementation, characteristics of the study sample, treatment completion rates, and selected presurgical and postsurgical functional and perceptual outcomes are presented. MATERIAL AND METHODS: Forty-six subjects were enrolled. Longitudinal evaluations of medical and dental histories, oromaxillofacial examinations, questionnaires, and sensory and functional tests were planned before and after surgery and after CP and IP treatment. Sample characteristics are described with descriptive statistics and comparisons of subject responses to questionnaire items at entry and postsurgical intervals were made with Fisher exact tests (alpha=.05). RESULTS: Conventional prostheses were completed in 33 of 46 subjects, and 16 of 33 CP subjects were treated with IP. Reasons for noncompletion of IP were recurrent/metastatic disease (16), refusal of implant therapy (7), lost to follow-up (4), treatment with a reconstruction plate (1), excessive radiation at implant sites (1), and death (1). All 16 recurrences/metastases occurred within 13 months of surgery. Only 3 of the 58 implants placed in 17 participants were considered failures. One failed due to lack of integration 31 weeks following placement, and 2 were buried due to unacceptable positioning for prosthetic restoration during denture fabrication. The remaining 55 implants were successful at final evaluation, ranging from 58 to 123 weeks following implant placement (mean duration=78.9 +/- 16.0 weeks). CONCLUSIONS: While 72% (33/46) of the subjects enrolled were able and willing to complete treatment with CP, only 35% (16/46) completed IP treatment. Careful consideration must be given to selection of the type of prosthetic rehabilitation and the timing of implant placement if an IP is planned.

Comparisons of chewing difficulty of consumed foods with mandibular conventional dentures and implant-supported overdentures in diabetic denture wearers.

PURPOSE: This study compared the chewing difficulty of foods in diets of denture wearers with mandibular conventional and implant-supported overdentures. MATERIALS AND METHODS: One-week dietary logs were evaluated for 58 subjects with controlled diabetes at baseline with their original dentures and with new dentures 6 months after treatment completion. Subjects received new maxillary and mandibular complete dentures, 21 with mandibular conventional dentures and 37 with implant-supported overdentures. A 10-point chewing difficulty rating scale (10 for most difficult-to-chew foods) was used to rate food items in the dietary logs. RESULTS: ANOVA showed no differences between the chewing difficulty mean scores for all foods consumed either at baseline or posttreatment for the two groups. However, the mean scores for the combined consumption frequency of difficult-to-chew foods (6 to 10) showed a significant decrease following treatment with both types of dentures. This decline did not differ significantly between the denture types. With original dentures, more than 91% of subjects consumed foods with chewing difficulty scores of 6 to 10 at least seven times per week. With study dentures, only 21% maintained this level of consumption, with the frequency decreasing to four to six times per week in 24% and one to three times per week in 43% of subjects. The declines in consumption frequency of more difficult to chew foods with study dentures were in a higher percentage of subjects in the implant than in the conventional group. CONCLUSION: After 7 months of adaptation to new dentures, patients consumed fewer difficult-to-chew foods than with their original dentures. This decline was more frequent with mandibular implant-supported overdentures than with conventional dentures. Dietary counseling should be considered as part of implant and complete denture therapy.

Implant-retained prostheses for facial defects: an up to 14-year follow-up report on the survival rates of implants at UCLA.

PURPOSE: An analysis of retrospective data was conducted to establish the survival rates of osseointegrated implants used to retain orbital, nasal, and auricular prostheses over a 14-year period and to recommend guidelines in the restorative treatment of such facial defects. MATERIALS AND METHODS: Included in this study were all patients who received implant-retained prostheses for auricular, nasal, or orbital defects from 1987 to 2001 in the Maxillofacial Clinics at the UCLA and City of Hope Medical Centers. Data were obtained from patient charts. Two methods were used to determine survival rates: (1) the percentage of the total exposed implants that survived was determined, and (2) life table analysis was used to calculate cumulative survival rates at different time intervals. RESULTS: A total of 207 implants were placed in 72 patients, and 182 implants had been uncovered. During the study period, 35 implants failed to integrate, and the survival rate for all exposed implants was 80%. Auricular implants showed the highest survival rate (95%), and orbital implants showed the lowest survival rate (53%). The life table analysis demonstrated a cumulative 6-year survival rate of 92% for auricular implants and 87% for piriform/nasal implants. In contrast, the survival rate for orbital implants showed a steady downward trend and reached 59% at 66 months. CONCLUSION: It is possible to achieve high survival rates of implants in the auricular and piriform/nasal sites through careful presurgical and radiographic planning. The less favorable long-term survival of implants in the orbital rim, especially at irradiated sites, requires further study.

A randomized clinical trial comparing the efficacy of mandibular implant-supported overdentures and conventional dentures in diabetic patients. Part V: food preference comparisons.

STATEMENT OF PROBLEM: The functional benefits of replacing old dentures with new conventional mandibular dentures or implant-supported overdentures has not been fully determined. PURPOSE: This study assessed the impact of these 2 types of replacement dentures on the food choices of diabetic patients. MATERIAL AND METHODS: A total of 68 diabetic patients with original complete dentures participated in this study. Diabetes was controlled with insulin in 38 patients (IT) and without insulin in 30 patients (NIT). All subjects received conventional maxillary dentures; 25 received mandibular conventional dentures (CD), and 43 received overdentures with plastic clips and a Hader bar attached to 2 osseointegrated implants (IOD). Subjects rated their perceptions of taste acceptability, texture acceptability, and chewing ease on a 4-point nominal scale and eating frequency on a 5-point scale for 13 specific foods at baseline (with original dentures) and at 6 months post-treatment completion (PTC). Fisher exact tests were used to compare the change in percentage distributions of responses with treatment. A 2 x 2 x 2 repeated-measures analysis of variance (ANOVA) was performed to compare mean scores between the 2 denture groups, 2 diabetic groups, and 2 time intervals for each of the 13 foods and 4 questions related to food acceptability. RESULTS: At baseline, no significant differences were found between the frequency distributions of responses in the CD and IOD groups or the IT and NIT groups for all 52 comparisons. With both types of study dentures, a higher percentage of patients perceived deterioration rather than improvement in function. When percentage distributions based on actual positive or negative change (treatment effect) in patient responses were compared, significant differences were found for 3 of the 52 responses, in favor of the IOD group. ANOVA demonstrated significant mean differences for 4 of the 52 comparisons. CONCLUSION: Both types of study dentures resulted in declines in the perceived taste and texture acceptability of almost all test foods. Declines in perceived chewing ease and eating frequency were more common and greater in the CD than in the IOD group. Both types of study dentures failed to affect food choices, as evidenced by declines or limited improvement in the perceived frequency with which most foods were eaten.