Search

Background and Objectives : Oral rehabilitation seeks to enhance mastication, a vital component of oral function that is compromised by tooth loss. This study aimed to assess the degree of improvement of masticatory performance in partially edentulous patients rehabilitated with removable partial dentures (RPD) or fixed partial dental prosthesis (FPDP). Changes in the occlusal contact area (OCA) and satisfaction with their chewing ability during the adaptation period were also evaluated. Materials and Methods : in total, 34 partially edentulous participants (median age 65.3 years; 56% women) who received an RPD or FPDP were assessed using masticatory performance assay, OCA calculation, and a visual analog scale (VAS). Results : Masticatory performance improved by 20% (range from 17% to 25%, p < 0.05) depending on the edentulism and the rehabilitation types. The OCA improved by 4.7 mm 2 ( p < 0.05) and satisfaction with the masticatory function improved by 9% ( p < 0.05) 3 months after prosthesis insertion. Conclusions : Conventional prostheses benefited partially edentulous individuals, improving masticatory performance by 20%. Treatment also increased the OCA in all types of partial edentulism, except in Kennedy class I patients rehabilitated with RPD. Patients' satisfaction with their chewing ability only increased in Kennedy class III patients rehabilitated with RPD.

Objective: Posterior edentulism reduces occlusal support, thus increasing the risk and symptoms of temporomandibular disorder. No previous study has explored its effect on the treatment of temporomandibular disorders. This study aimed to examine the relationship between neck posture, balance, and posterior edentulism in patients with temporomandibular disorder and compare the effectiveness of physical therapy. Methods: In a quasi-experimental controlled trial, 26 patients with temporomandibular disorder were divided into 13 in the partly edentulous group and 13 in the dentate group. Both groups received manual therapy, postural exercises, deep neck flexor stabilization, and Kinesio tapping for 6 weeks. Each participant completed 12 physiotherapy sessions, administered twice weekly, with a minimum interval of 48 hours between sessions. Outcomes were assessed at baseline and after the 6-week program, including pain, mandibular movement, posture, and balance. Results: The physical therapy program significantly improved all measured outcomes ( P < .05). Furthermore, the partially edentulous group showed more remarkable improvement in pain and balance compared to the dentate group ( P < .05). Conclusions: Postural exercises effectively alleviate symptoms in patients with temporomandibular disorder, with more significant improvements observed in the partially edentulous group than in the dentate group., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Unlabelled: Removable partial denture prostheses are still being used for anatomic, medical and economic reasons. However, the impact on chewing parameters is poorly described., Objectives: The objective of this study was to estimate the impact of removable partial denture prosthesis on masticatory parameters., Material and Methods: Nineteen removable partial denture prosthesis (RPDP) wearers participated in the study. Among them, 10 subjects were Kennedy Class III partially edentulous and 9 with posterior edentulism (Class I). All presented a complete and full dentate opposing arch. The subjects chewed samples of carrots and peanuts with and without their prosthesis. The granulometry of the expectorated boluses from carrot and peanuts was characterized by median particle size (D50), determined at the natural point of swallowing. Number of chewing cycles (CC), chewing time (CT) and chewing frequency (CF=CC/CT) were video recorded., Results: With RPDP, the mean D50 values for carrot and peanuts were lower [Repeated Model Procedures (RMP), F=15, p<0.001] regardless of the type of Kennedy Class. For each food, mean CC, CT and CF values recorded decreased (RMP, F=18, F=9, and F=20 respectively, p<0.01). With or without RPD, the boluses' granulometry values were above the masticatory normative index (MNI) determined as 4,000 µm., Conclusion: RPDP rehabilitation improves the ability to reduce the bolus particle size, but does not reestablish fully the masticatory function., Clinical Relevance: This study encourages the clinical improvement of oral rehabilitation procedure.

The aim of this study was to axiographically analyse the mobility of the condyles of the temporomandibular joints in patients with partial edentulism in lateral sections and try to specify whether the partial edentulism has an impact on the severity of temporomandibular disorders. 60 subjects with partial edentulism (different range groups) and 20 subjects in the control group (full dental arches) were examined. Every patient underwent a thorough clinical examination, including axiography conducted by means of Cadiax Compact II® system. The results show some correlation between the advancement of temporomandibular joint disorder, the range of partial edentulism and the abrasion of the residual teeth. In the study, a significant intensification of dysfunction symptoms and restricted condylar path was observed in patients with the largest partial edentulism and significant level of tooth wear of the residual teeth. A significantly higher percentage of asymptomatic subjects or those with minor dysfunction was also found among the patients with lowest-range partial edentulism in lateral sections.

Background: The purpose of this study was to locate the main occluding area when the reduced posterior occlusal support was treated with an implant-supported prosthesis and to evaluate the subsequent improvement in the masticatory ability as compared with removable partial dentures., Methods: Twenty-six patients with implant prostheses and 24 patients with removable partial dentures were recruited for this study. All patients had partially lost their posterior occlusal support. The first molar region in any quadrant was always included in the prosthetic region. Each subject was instructed to clench a piece of temporary stopping as a test food on the occluding area that was preferably used during mastication. The main occluding area was judged by locating the tooth on which the temporary stopping rested during clenching. Subjective masticatory ability was self-assessed by means of a questionnaire., Results: The main occluding area of the subjects in the implant group was located more posterior compared with the removable partial denture group. The level of masticatory ability in the implant group was the same as that in the control group., Conclusions: The location of the main occluding area and the masticatory ability of the subjects with implants were equivalent to those with healthy natural dentition., (© 2012 Australian Dental Association.)

The aim of this in vitro study was to investigate the strain distribution of the compressed mandible bone under the applied restoration- removable partial denture and to compare with the same but unrestored mandible under vertical (occlusal) load and to find out whether removable partial denture-restored or unrestored mandible causes greater strain effect on supporting tissue. Four mandible models were tested during loading for the purpose of strain measuring. Digital image correlation system (GOM - German Optical Measuring, Braunschweig, Germany), used for measuring strain consists of two digital cameras and software ARAMIS (6.2.0, Braunschweig, Germany). Remaining teeth suffer from greater strain in the mandible model without removable partial denture (7.5-10%). On the contrary, mandible with removable partial denture shows the maximum strain below the denture saddle (3.5%). However, it can be noticed that the marginal bone of the second lower praemolar in both experimental models is deformed whether the mandible model has (2.8%) or has not (10%) replacement. Within the limitations of this study the higher strain is observed in mandible model without replacement and the strain is limited locally, in the bone region that surrounds remaining teeth and mental foramen.

Background: The purpose of this study was to investigate the differences in location of the main occluding area with reduction of occlusal support and to evaluate the subsequent impairment in masticatory ability., Methods: One hundred and two patients were recruited according to the Eichner's index, which is based on the number of occlusal support zones. Each subject was instructed to clench a piece of temporary stopping in the particular occluding area that was preferably used during mastication. The main occluding area was judged by locating the tooth on which the temporary stopping rested. Subjective masticatory ability was self-assessed by means of a questionnaire., Results: Group classification depending upon the location of the main occluding area was significantly associated with the category of the Eichner's index. The level of masticatory ability was significantly associated with the category of the Eichner's index. Moreover, masticatory ability was significantly more impaired in subjects with main occluding areas at the premolar regions compared to those at the molar regions., Conclusions: The location of the main occluding area may differ under the influence of the remaining natural teeth. The location of the main occluding area and the masticatory ability are likely to be closely related.

Background: In the shortened dental arch condition, little is known of how patients adapt their jaw function during mastication to the new oral environment. This study aimed to investigate the changes in mandibular movements when the chewing region was changed from the first molar to the first premolar., Methods: Thirty clinical residents with natural dentitions were recruited. The subjects were asked to chew a piece of beef jerky using either the first molar or the first premolar on the preferred chewing side. Three-dimensional trajectories of lower incisors and both condyles were analysed using a jaw movement tracking device with six degrees of freedom during the period between the onset and offset of electromyographic bursts from the masseter and anterior temporal muscles., Results: The closing angle of the lower incisors for first premolar chewing was narrower in comparison with that for first molar chewing (p < 0.05). The lengths of the condylar trajectories and the maximum velocities of the condylar movement for first premolar chewing were smaller and slower, respectively, in comparison with those for first molar chewing (both sides; p < 0.01)., Conclusions: The mandibular movement during mastication might be changed to adapt the premolar chewing because of a loss of posterior occlusal supports.

Due to large individual differences of masticatory function, an inter-individual comparison between denture patients and complete dentate people would be insufficient. This cross-sectional study aimed to evaluate patients' masticatory performance (determined by Mixing Ability Index, MAI) and bite force (determined by maximum bite force, MBF) after removable partial denture (RPD) treatment by comparing those of the RPD replaced side with those of their own opposite dentulous side, and to evaluate influence of bite force on masticatory performance in different dentitions. Subjects included patients with unilateral distal extension RPDs (n=28). Apart from the RPD replaced area on one-side, all subjects had intact dentitions. Both masticatory parameters were evaluated separately on each chewing side. MAls and MBFs obtained from the RPD replaced side (0.65 +/- 0.50 and 220 +/- 155 N, mean +/- SD) were significantly lower than those from the dentulous side (1.06 +/- 0.64 and 450 +/- 268 N; Wilcoxon signed-ranks, P < 0.001). MBF significantly influenced MAI in both RPD replaced (Univariate linear regression; R2 = 0.17, P < -0.001) and dentulous sides (R2 = 0.51, P < 0.001). After RPD treatment, masticatory performance and bite force of RPD replaced side were lower than those of their own dentulous side. The influence of the bite force on masticatory performance in RPD replaced side was less significant than that in the dentulous side.

Endosseous oral implants have been used as orthodontic anchorage in subjects with multiple tooth agenesis, and their application under orthodontic loading has been demonstrated clinically and experimentally. The aim of this investigation was to examine three-dimensional (3D) bone and implant finite element (FE) models. The first model assumed that there was no osseointegration and the second that full osseointegration had occurred. These models were used to determine the pattern and distribution of stresses within the ITI-Bonefit endosseous implant and its supporting tissues when used as an orthodontic anchorage unit. The study examined a threaded implant placed in an edentulous segment of a human mandible with cortical and cancellous bone. The results, using both models, indicated that the maximum stresses were always located around the neck of the implant, in the marginal bone. Thus, this area should be preserved clinically in order to maintain the bone-implant interface structurally and functionally.

The aim of this study was to clarify the relationship between partially edentulous pattern and the masticatory function in removable partial denture wearers. Eighty eight removable partial denture wearers and 7 subjects with intact dentition volunteered for this study. Using the Eichner's index, all subjects were divided into 6 groups. Electromyographic (EMG) activities of the masticatory muscle were recorded during chewing a piece of raw carrot. The masticatory function was analyzed by using the variation coefficient (VC) of the time parameter of EMG interval recorded during mastication. The association of the VC with group classification based on Eichner's index was analyzed using analysis of covariance with gender and age as the covariates. The result of the analysis revealed that the VC was significantly associated with group classification and the patients in groups without posterior occlusal supports exhibited significantly higher VC values than those in groups with posterior occlusal supports. These findings suggested that the reduced function in patients without the posterior occlusal contacts was difficult to attain improved and satisfactory outcome with removable partial dentures and that there is a significant need for posterior occlusal support for the preservation of masticatory function.

This study evaluated the effect of oral cancer surgery on masticatory efficiency. Masticatory efficiency was measured using the ATP absorption method. Eating ability was measured using a questionnaire. Two groups were employed as controls: The "normal occlusion group" consisted of subjects who had a complete set of natural maxillary teeth opposed to mandibular teeth, and the "unilateral occlusion group" consisted of subjects who had lost their molar and premolar teeth on one side of the mandible as a result of caries or periodontal diseases. Three treatment groups, each of 6 patients, were studied: a glossectomy group, a marginal mandibulectomy group and a segmental mandibulectomy group. There were no differences in masticatory efficiency between two control groups. Masticatory efficiencies of the three oral cancer treatment groups were lower than in the unilateral occlusion group, even 12 months after surgery. Masticatory efficiency of the glossectomy group was significantly higher 12 months after surgery compared with pre-surgery. Masticatory and eating abilities of the marginal mandibulectomy group and the segmental mandibulectomy were reduced at 3 and 6 months after surgery. The masticatory efficiency 12 months after surgery was higher in the marginal mandibulectomy group than the segmental mandibulectomy group, although the difference was not statistically significant. The self assessed eating ability 12 months after surgery was significantly higher in the marginal mandibulectomy group than the segmental mandibulectomy group. These results suggest that discontinuation of the mandible may lead patients to eat only foods that do not require a substantial amount of chewing. Hence, the quality of life of patients in the marginal mandibulectomy group was considered to be better than that in the segmental mandibulectomy group.

Reduction of the size of food platform of a distal extension removable partial denture has been recommended to decrease functional load on the abutment teeth and residual ridges. The purpose of this study was to investigate the influence of shortening food platform on masticatory performance. Eight subjects unilaterally missing mandibular molars participated in the study. A unilateral design was used for the denture framework. The length of the food platform was changed as follows. Initially, (A) was adjusted so that the distal end of the platform was in accordance with the distal end of maxillary second molar. Next, the platform was shortened successively to 15 mm (B) and 10 mm (C). Subjects were asked to masticate 2-colored wax cubes to evaluate masticatory performance. Mixing Ability Index was calculated from the color mixture and the form of masticated cubes. Repeated measures one-way ANOVA indicated significant difference of Mixing Ability Index among platforms (P < 0.0001). The Dunnett's test indicated no significant difference between A (1.27 +/- 0.29) and B (1.36 +/- 0.29), and a significant difference between A and C (0.89 +/- 0.30), (P < 0.001). Masticatory performance decreased significantly when the length of food platform was shortened to 10 mm.

The mandible and maxilla of two edentulous women, treated during 25 weeks with oral pamidronate, were monitored by peripheral quantitative tomography (pQCT). Whole bone volumetric mineral density failed to show meaningful variations after treatment. However, an analysis of separated cortical and medullar areas disclosed focal bone loss at the right mandible cortex of patient #1 and at the left maxilla cortex of patient #2. These and other bone sub-regions were further studied by clustering the internal sites with a different degree of bone mineral density, resorting to the mineral threshold analysis provided by the system. Where bone loss was detected, it corresponded to increased loss of the most osteopenic sites, while medium and high-density portions tended to remain unchanged within the region. There were no significant variations in all other regions, or alternatively, minor losses at osteopenic sites were compensated by an increase at high-density portions. Hence, the pQCT system allowed monitoring volumetric bone mineral density at particular sites of interest, discriminating variations at portions with a dissimilar degree of bone volume. Further studies should confirm whether pamidronate exerts a protective effect on sub-regions with previous medium and high degrees of bone mineralization, as suggested by our present findings.

Interocclusal recording for removable partial denture in bilateral mandibular distal extension were evaluated for the differences of the interocclusal recording material utilized during different impression techniques. The purpose of this study is to develop interocclusal recording utilizing occlusion rims with high accuracy. The intraoral model with urethane rubber mucosa with 3 metallic spheres as measuring points was utilized. With the applied pressure (functional) and minimum pressure (anatomical) impression techniques, working casts were fabricated. Interocclusal recording was registered with the occlusion rim on the intraoral model unto the articulator by applying the interocclusal materials; paraffin wax (PW), ALUWAX (AW), impression paste (IP) and Exabite II (EB). Analyses were conducted with the three-dimensional analyzer and calculated for the amount of vertical and antero-posterior displacement between the intraoral model and the working cast. The results were that PW had the greatest displacement, especially with the functional impression technique, while AW had minimum displacement especially in the posterior direction. With the functional impression technique utilizing AW was revealed to minimize the amount of interocclusal displacement.

Practical laboratory procedures were suggested in order to provide a modified occlusal anatomy to reduce implant loading. The concept of differential mobility caused by the flexion between a natural tooth/periodontal ligament interface with its supporting bone, compared with the stiffness of the implant/bone interface, was described. When individual tooth-supported and implant-supported prostheses coexist in the same arch, this differential mobility can shift the loading disproportionately from the natural teeth to the implants. A new concept of therapeutic differential loading is introduced and a clinical technique of differential occlusal adjustment is described to bring about a more favorable distribution of loading to all the supporting bone. Long-term natural tooth intrusion can cause implant overload. Therefore, it is suggested that periodic differential occlusal adjustment procedures be used to re-establish a long-term balance of loading between individual implant- and tooth-supported prostheses within the same arch.