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200Pakistan Oral & Dental Journal Vol 33, No. 1 (April 2013)

Masticatory Efficiency between Balanced and Lingualized Occlusion

ORIGINAL ARTICLE

INTRODUCTION

The World Health Organization (WHO) defineshealth as a state of complete physical, mental andsocial well-being, not merely the absence of disease orinfirmity. This modern approach to health lends itselfto oral health as well.1 Loss of teeth results in compro-mised facial aesthetics and loss of function. It is a verydifficult situation, even worse when the patient iscompletely edentulous.2 Most of the edentulous pa-tients are rehabilitated by providing them with com-plete dentures.3,4

The success of complete dentures is related to thequality of the impressions and chewing efficiency ofthe patients.5 The scheme of occlusion of complete

denture is one of the factors which affects the chewingpattern and masticatory efficiency of the patients.6

With dentures, the quantity and the intensity of con-tacts determine the amount and the direction of theforces that are transmitted through the bases of thedenture to the residual ridges. That is why the occlusalscheme is considered an important factor in the designof complete dentures.7,8

Both balanced occlusion and lingualized occlusionare recommended for complete dentures. Anatomicalas well as non-anatomical molds of teeth can be usedin both concepts. Balanced articulation is described asthe occlusal contacts of maxillary and mandibularteeth initially in maximum intercuspation, and theircontinuous contacts during movements from this posi-tion along specific working, balancing and protrusiveguidance pathways developed on the occlusal surfaceof the teeth. It is considered an ideal occlusion forcomplete dentures.9

Lingualized occlusion gives the patient improvedcomfort, function and appearance, quality-of-life goalssought by the clinician and patient alike. The principleof lingualized occlusion aims at stabilizing the

MASTICATORY EFFICIENCY BETWEEN BALANCED AND LINGUALIZEDOCCLUSION IN COMPLETE DENTURE WEARERS

1ABDUL RAZZAQ AHMED, BDS, FCPS (PROSTHODONTICS)2MUHAMMAD USMAN MUNEER, BDS, FCPS (PROSTHODONTICS)

3SAMAN HAKEEM, BDS, FCPS (PROSTHODONTICS)

ABSTRACT

The objective of the study was to compare the masticatory efficiency with balanced occlusion andlingualized occlusion in complete denture wearers. The study was conducted in the Department ofProsthodontics, Lahore Medical & Dental College, Lahore. Sixty edentulous patients were includedin this study; patients were randomly divided into two groups by using Statistical Package for SocialSciences (SPSS version 10) software. Group A was provided with dentures fabricated with bilateralbalanced occlusion and Group B with lingualized occlusion. The patients masticatory efficiency wasassessed after 2 months of denture insertion using the sieving method. Masticatory efficiency wasstatistically better in patients provided with complete dentures fabricated with lingualized occlusionthan dentures with bilateral balanced occlusion. It was concluded patients provided with denturesfabricated with lingualized occlusal scheme were more comfortable with their dentures and were ableto chew properly with ease and comfort.

Key Words: Lingualized occlusion, bilateral balanced occlusion, masticatory efficiency.

Correspondence: 1Dr. Abdul Razzaq Ahmed, House No. 596 PIBColony, Karachi. Email Address: [email protected] Number: +92-321-2497682 Assistant Professor & HOD, ofProsthodontics, Jinnah Medical and Dental College, Karachi

2 Assistant Professor, of Prosthodontics, Lahore Medical and Den-tal College, Lahore,

3 Assistant Professor & HOD of Prosthodontics, Bahria UniversityMedical and Dental College, Karachi

Received for Publication: January 1, 2013Revision Received: February 2, 2013Revision Accepted: February 11, 2013



prosthesis. It is based on maxillary palatal cuspsfunctioning as the main supporting cusp in harmonywith the occlusal surfaces of mandibular teeth.10

To date, it is unclear if patients notice differencesin their ability to chew when they wear completedentures manufactured with lingualized occlusalscheme when compared with dentures made with abilateral balanced occlusion in Pakistan. Therefore, itwas the aim of this study to compare the masticatoryefficiency with two differently fabricated occlusalschemes of complete dentures.

METHODOLOGY

Sixty edentulous patients between the ages of 45 65 years with no previous complete denture experi-ence reporting to the Department of Prosthodontics forprovision of new complete dentures were included inthis study. Patients having any soft tissue abnormal-ity e.g. epulis fissuratum, hyperplasia were excludedfrom the study. Likewise, patients having any con-genital defects, neurologic/psychiatric disorders werealso excluded.

Patients of both genders were randomly distrib-uted into two groups in order to minimize the con-founding effect of this variable (gender). Completemedical/dental history, clinical examination and in-vestigations including periapical radiograph andorthopantomogram if required were carried out. Con-sent was obtained in this regard from the patients.

A computer was used to randomly divide 60 pa-tients into two groups of 30 each, i.e. Group A andGroup B by using Statistical Package for Social Sci-ences (SPSS version 10) software. Later on, as thepatients came, they were numbered in a sequence of 1-60 according to date of arrival in the department andplaced into these pre-sorted groups. Group A patientswere provided with complete dentures fabricated withbilateral balanced occlusal scheme while those in GroupB were provided with complete dentures fabricatedwith lingualized occlusal scheme.

Upper and lower complete dentures were con-structed by the same clinician following standardizedclinical techniques. The teeth setup of complete den-tures with lingualized occlusion was arranged as fol-lows: the functional maxillary palatal cusps of the

posterior teeth were set in the central groove of themandibular posterior teeth in lateral and protrusiveexcursions. The maxillary buccal cusps were elevatedand had no contact with the mandibular buccal cuspsin both centric and eccentric movements. The 200 semi-anatomic commercial artificial teeth (Simpler AC,manufactured by Yamahachi Dental MFG.CO. Japan)were used for the lingualized occlusion groups teetharrangement.

The teeth setup of complete dentures with bilat-eral balanced occlusion was arranged as follows: thefunctional maxillary palatal cusps of posterior teethwere set in the central groove of the mandibular teeth,and the maxillary buccal cusps were kept in contactwith mandibular buccal cusps. The buccal cusps andpalatal cusps were in articulation and functional in thebilateral and protrusive excursions. The 200 semi-anatomic commercial artificial teeth (Naperce, manu-factured by Yamahachi Dental MFG.CO. Japan) wereutilized for the bilateral balanced occlusion groupsteeth arrangement.

After the teeth setup, trial of the denture wascarried out in the patients mouth. After necessarylaboratory procedures by the same technician in thedental laboratory within the institution, final prosthe-ses were inserted. After insertion, in both groups,necessary occlusal adjustments were done. Instruc-tions were cited and follow-up visit scheduled. Whenthe patients were free of post insertion complaintsthen patient masticatory efficiency was assessed after2 months of denture insertion.

Masticatory efficiency test was conducted usingSieving method. Two tests were conducted using 15gms peanuts in each test. Peanuts were divided intofive portions of 3 gms using an electrical balance (ANDHR-200 by AND company limited, Japan) for each test.In the first test, patients were asked to chew eachportion for 15 seconds and spit out the contents in agiven container. Patients were given a tumbler ofwater and were asked to rinse thoroughly and releasethe remaining contents in the same container. Theprocedure was repeated 5 times with every portion of3 gm peanuts. The chewed material was collected,pooled and passed through a 10-mesh screen sieve(U.S. Standard Testing Sieve by Mughal Test, Paki-stan). Second test was conducted using same



methodology but patients were asked to chew eachportion till the material was ready to swallow. Rest ofthe methodology was kept same. The chewed materialwas left on a blotting paper for 30 minutes after it waspassed through the sieve and weighed using an electri-cal balance with an accuracy of 0.01g for both the tests.Mean of both tests were calculated and analyzed.

Data were entered to statistical software SPSS(version 10) for analysis. The variables under studywere age; gender and weight of masticated peanutsafter 15 second and at swallowing threshold with time.Mean with standard deviation, 95% confidence inter-val, median with IQR were computed for age andweight of masticated peanuts after 15 second and atswallowing threshold with time. Qualitative variable(gender) was calculated as frequency and percentage.Non-parametric Mann-Whitney U test was appliedinstead of independent sample t test due to not normalcontinuous variables for significance of patients mas-ticatory efficiency will be compared of both. Chi Squaretest was also applied to compare gender proportionbetween groups. Significance level was set at p 0.05.

RESULTS

A total of 60 edentulous patients were included inthis study. Patients were divided into two groups of 30each by random numbering table marked as A and B.The average age of the patients was 53.634.5 years(95%CI: 52.47 to 54.8). The mean weights of masti-cated peanuts after 15 seconds and at swallowingthreshold with time are presented in table 1. Out of 60patients, 34(56.7%) were male and 26(43.3%) werefemale with 1.31:1 male to female ratio. In group A18(60%) were male and 12(20%) were female while ingroup B, 16(53%) were male and 14(46.7%) were

female. Significant difference was not observed be-tween the groups for gender distribution (Chi-Squarevalue= 0.27 DF= 1 P-value= 0.602).

Comparison of weight (mean weight of 5 timeswith every portion of 3 gm peanuts) of masticatedpeanuts after 15 seconds between groups is presentedin figure I. The median (IQR) of mean weight ofmasticated peanuts after 15 seconds was 2.22(0.56) gin lingualized occlusion groups and 2.27(0.26) g inbalanced occlusion groups. Median difference was notstatistically significant between the groups (Mann-Whitney U test= 375, p=0.267). The average of meanweight of masticated peanuts after 15 seconds for bothgroups is also presented below the figure 1.

Comparison of weight (mean of 5 times with everyportion of 3 g peanuts) of masticated peanuts at swal-lowing threshold between groups is presented in fig-ure 2. The median (IQR) of mean weight of masticatedpeanuts at swallowing threshold was 1.24(0.52) g inlingualized occlusion groups and 1.47(0.46) g in bal-anced occlusion groups. Median difference was statis-tically significant between the groups (Mann-WhitneyU test= 307, p=0.034). The median weight of masti-cated peanuts was significantly low in lingualizedocclusion groups than balanced occlusion groups atswallowing threshold. Comparison of time (sec) ofswallowing threshold of masticated peanuts betweengroups was also not significant as shown in figure 3.

DISCUSSION

The statistically significant result of this studyproved the hypothesis that masticatory efficiency isbetter with complete dentures fabricated by lingualizedocclusal scheme as compared to those fabricated bybilateral balanced occlusal scheme.

TABLE 1: DESCRIPTIVE STATISTICS OF STUDY VARIABLES (n= 60)

Study Variables (Unit) Mean SD 95% CI Median(IQR) Max - Min

Age (Years) 53.63 4.5 52.47 to 54.8 53 (8) 60 46

Mean weight (gm) of masticated 2.187 0.30 2.11 to 2.26 2.3(0.28) 2.69 1.57peanuts after 15 seconds

Mean weight (gm) of masticated 1.31 0.37 1.21 to 1.40 1.4(0.47) 1.92 0.48peanuts at swallowing threshold

Time (sec) of swallowing threshold 51.84 16.53 47.57 to 56.1 49.1(21.7) 93.97 26.7

CI = Confidence Interval, IQR = Interquartile range, Max = maximum observation,Min = Minimum observation, sec = seconds, gm = grams, SD = Standard Deviation



Patients provided with dentures fabricated withlingualized occlusal scheme were more comfortablewith their dentures. They were able to chew properlywith ease and comfort. No such study was conductedbefore in Pakistan to assess the masticatory efficiencyof patients by comparing both the occlusal schemes.

In order to minimize the confounding effect of age,45 to 65 year age group was included in the study.Patients below the age of 45 years were not included inthe study in which neuromuscular coordination isbetter and might have confounded the study withreference to patient masticatory efficiency level.11

In the dental literature, many reports have beenpublished showing that professionally assessed qual-ity of complete dentures does not agree with patientssubjective judgments.12 Awad and Feine13 as well as

Heydecke et al14 suggested that patients satisfactionwith their prostheses could not be inferred from theclinicians impression of and satisfaction with newlyprovided prostheses. Therefore, the focus of this studywas on patient chewing efficiency as the main out-come.

In this study, patients showed their ability to chewand masticate significantly better when provided den-tures were fabricated with lingualized occlusal scheme.Koide15 investigated the masticatory performance ofedentulous patients wearing complete dentures ar-ranged with lingualized occlusion and bilateral bal-anced occlusion. It was found that lingualized occlu-sion offered a higher ability of food crushing, showedhigher masticatory efficiency, displayed faster as well

Fig. 1: Comparison of weight (gm) of masticated peanuts after 15 seconds between groups

Statistics Balanced occlusion Lingualized occlusion P-Value

Median (IQR) = 2.27(0.26) gm 2.22(0.56) gm 0.267

Mean SD = 2.230.27 gm 2.140.32 gm

Mann-Whitney U test (two tailed) = 375

Box and whisker plot shows median comparison between groups. Block line in the box shows median of meanweight of masticated peanuts. Small circles show outliers.

Gm = grams.



as smoother masticatory movement, and showedchewing patterns that were closer to the chopper typecompared with bilateral balanced occlusion.

The result of this study also confirms the findingsby Gomibuchi et al16 who compared dentures withanatomical teeth either arranged for bilateral bal-anced or lingualized occlusion dentures. Patients inhis study expressed better chewing ability withlingualized occlusion dentures, suggested thatlingualized occlusion is effective in masticating or cutfood, and are the form of occlusion having a highcutting potential compared to bilateral balanced oc-clusion.

Kimoto et al17 in the study found that edentulouspatients provided with complete dentures fabricatedwith lingualized occlusal scheme experienced and ex-

pressed greater satisfaction with their denture reten-tion and resulted in greater masticatory performance.

However Ono and Hatake18 did not found anysignificance in complete dentures arranged withlingualized occlusal scheme affecting masticatory per-formance. It was reported that the chewing ability ofpatients with lingualized occlusion and those withbilateral balanced occlusion was 44.5% and 46.8%respectively.

Heydecke et al19 compared the masticatory effi-ciency between complete dentures arranged with ca-nine guided occlusion and lingualized occlusion. Hefound that patients provided with complete denturesof canine guided occlusal scheme showed better mas-ticatory ability compared to complete dentures ar-ranged with lingualized occlusion.

Fig. 2: Comparison of weight (gm) of masticated peanuts at swallowing threshold between groups


Median (IQR) = 1.47(0.46) gm 1.24(0.52) gm 0.034*

Mean SD = 1.400.46 gm 1.210.35 gm


Box and whisker plot shows median comparison between groups. Block line in the box shows median of meanweight of masticated peanuts. Small circles show outliers

Gm = grams.



A number of authors have proposed a lingualizedocclusal scheme as the most beneficial concept forcomplete dentures.20

The complete dentures arranged with lingualizedocclusion significantly affect masticatory efficiency.The concept of lingualized occlusion ought to be apply-ing in prospect for fabrication of complete dentures.With the use of specific moulds of teeth, the scope andpracticality of lingualized occlusal scheme can bringforward favorable results in terms of patients satis-faction with different types of prosthesis.

CONCLUSIONS

Within the limitations of this study, the conclusionis that the masticatory efficiency was higher in pa-tients who were provided with complete denturesfabricated with the lingualized occlusal scheme ascompared to those patients who received complete

dentures made with balanced occlusal scheme. Thiswas due to the fact that lingualized occlusal techniqueresulted in functionally better complete dentures ascompared to the ones made by balanced occlusal tech-nique. In addition to that more research work needs tobe carried out in our population to assess the benefitsof these occlusal schemes in the fabrication of partialdentures and other prosthesis as well.

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3 Anastassiadou V, Robin HM. The effect of denture quality attri-butes on satisfaction and eating difficulties. Gerodontology2006; 23: 23-32.

Fig. 3: Comparison of time (sec) of swallowing threshold of masticated peanuts between groups


Median (IQR) = 46.6(20.5) sec 49.6(20.9) sec 0.37

Mean SD = 50.316.5 sec 53.416.7 sec


Box and whisker plot shows median comparison between groups. Block line in the box shows median of meantime of masticated peanuts. Small circles show outliers

Sec = seconds.



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