SYNOPSIS

DR. ANIL K. SUBHASH

POST GRADUATE STUDENT

DEPARTMENT OF PROSTHODONTICS

INCLUDING

CROWN & BRIDGE AND IMPLANTOLOGY

K.V.G.DENTAL COLLEGE & HOSPITAL,

KURUNJIBHAG, SULLIA (DK) KARNATAKA, 574327

Rajiv Gandhi University of Health Sciences, KarnatakaBangalore

1. / Name of the Candidate and Address / DR. ANIL K. SUBHASH
POST GRADUATE STUDENT,
DEPARTMENT OF PROSTHODONTICS
K.V.G.DENTAL COLLEGE & HOSPITAL,
KURUNJIBHAG, SULLIA(DK)
KARNATAKA,INDIA-574 327
2. / Name of the Institution / K.V.G.DENTAL COLLEGE & HOSPITAL,
KURUNJIBHAG, SULLIA(DK)
KARNATAKA,INDIA-574 327
3. / Course of study and subject / MASTER OF DENTAL SURGERY
PROSTHODONTICS
INCLUDING CROWN & BRIDGE AND IMPLANTOLOGY
4. / Date of admission to course / 28-5-2010
5. / Title of The Thesis:-A study of influence of mandibular residual ridge shape on masticatory efficiency of complete denture.
6.
7
/ Brief resume of the intended work :
6.1 Need for the study :
Dental prosthesis is an indispensable means for functional and esthetic rehabilitation of an edentulous patient to improve his/her oral health along with the relative quality of life1. However, the reduction in masticatory efficiency may lead to changes in dietary selection with risk of impaired nutritional status in the elderly complete denture wearers2.
The masticatory efficiency in complete denture wearers is influenced by many factors. The factors can be grouped into two main categories: factors related to proper design and fit of prosthesis (denture related factors), and factors related to morphologic, physiologic, and psychological parameters (patient related factors)3.As the shape of the ridge is deformed by resorption; the denture bearing area, volume, and height of the ridge are altered4 .
Panoramic radiographs were previously used for evaluation of the mandibular residual ridge morphology. However, it is difficult to determine the soft tissue morphology from radiographic evaluation and it is limited only to one part of the mandible and merely represents the height of the residual ridge7.Thegraph sheet method was also been used to measure the basal seat areas8. This method is very technique sensitive and conversion of a three dimensional surface area into a two dimensional graph sheet is not always reliable.
Hence this study is designed to elucidate the influence of the shape of the mandibular residual ridge (area, height, and volume) on the masticatory efficiency of a complete denture wearer using computer aided designing (CAD) technology.
6.2 Review of literature
The reduction of residual ridge is a multifactorial biomechanical disease that results from a combination of anatomic, metabolic, and mechanical determinants.3 The shape of the edentulous residual ridge influences support and retention of the complete denture.3 It is important to evaluate denture foundation (the oral structure available to support a denture) for predicting successful prosthodontic treatment, especially in complete denture wearers.3
The masticatory efficiency will be influenced greatly by the amount of the basal seat area than the height and/or the volume of the residual alveolar ridge.4
It is observed that the speed of chewing for fine and coarse food do not vary in complete denture wearers, whereas the coarse particles are ground more rapidly than the fine particles in case of natural dentition.5 This is due to the reduced efficiency of food transport by the tongue and cheeks because of their added function of retaining the dentures.5
It is also found that denture may demonstrate some degree of movement during function even if it does not exhibit movement during clinical examination.6 Hence the assessment of denture fit in the passive state by clinical examination is not a good predictor of denture performance.A periodic recall system to evaluate denture performance as well as the integrity of the supporting tissue should be an integral component of denture treatment.6
6.3 Objectives of the study:
  1. To evaluate the effect of mandibular residual ridge area on masticatory efficiency in complete denture wearers
  1. To evaluate the effect of mandibular residual ridge height on masticatory efficiency in complete denture wearers
  1. To evaluate the effect of mandibular residual ridge volume on masticatory efficiency in complete denture wearers
  1. To compare the effects of mandibular residual ridge area, height and volume on masticatory efficiency in complete denture wearers
Materials and methods :
7.1 Source of the data
For the purpose of study on the influence of mandibular residual ridge shape on masticatory efficiency in complete denture wearers, it is decided to select 30 subjects, comprising both male and female, those had been treated with complete dentures in the department of prosthodontics and crown and bridge of the K.V.G. Dental college and hospital, Sullia.
Inclusion criteria
1. Age 45-65 years
2. Denture wearers with informed consent
3. Dentures with semi anatomic teeth
4. Period of edentulousness ranges from 6 months to 1 year
5. No trouble in daily use of denture for at the least of 3 months before the study.
Exclusion criteria
1. Ill-fitting denture
2. Denture wearers without informed consent
3. Soft and hard tissue oral pathology
4. Poor neuromuscular control
5. Severely attreted denture
6. Medically compromised condition
7.2.Methods of collecting data
  1. Instrument and material used during course of study
Instruments
1. 5-,10-,20-,40- mesh sieves
2. 50 cc Centrifugal tube
3. Collecting cup
4. Glass stirrer
Materials
1.Elastomeric impression material
2.Peanut
Equipment
1. Centrifugal machine
2. Cercon eye scanner
3. Digital weighing machine
  1. Methodology :
Thirty complete denture wearers will be examined. The mandibular residual ridge of each subject will be evaluated by a replica of the ridge obtained with silicone impression material filled and rubbed off against the denture border onto the tissue surface of the denture. The masticatory efficiency in each subject will be evaluated as follows. Each subject will be instructed to masticate 3 gms of peanuts 20 times on their habitual chewing side, and all the particles will be collected in a cup. This trial will be repeated thrice.
  1. Collection of data:
The basal seat area of each replica will be measured by cercon eye scanner. The volume (weight of the replica/specific gravity of silicone impression material) and the height (volume/basal area x 2) of each replica will also be calculated.
All pea nut particles will be sieved by 5-, 10-, 20-, and 40-mesh sieves. The volume on each sieve will be measured in a centrifuge tube after centrifugation for 3 minutes at 1,500 rpm. Masticatory efficiency will be evaluated by the percentage of the particles that passed through the 5-mesh sieve.
  1. Statistical analysis
The study results will be analyzed using Karl Pearson’s coefficient of correlation
7.3Does the study require any investigations or interventions to be conducted on patients or other humans or animals?
Yes
7.4 Has the ethical clearance been obtained from your institution in case
7.3?
Yes
References
1Gunjandhir, david W. berzins, virendradhuru – Physical properties of denture base resins potentially resistant to candida adhesion. (J. prosthodont 2007; 16:465-72.)
2Gunnar E. Carlsson, OdontDr, DrOdonthc-Clinical morbidity and sequelae of treatment with complete dentures. (J Prosthet Dent 1997;79:17-23.)
3HisashiKoshino, Toshihiro Hirai, Tsutomu Ishijima, Koji Ohtomo-Influence of Mandibular Residual Ridge Shape on Masticatory Efficiency in Complete Denture Wearers.( Int J Prosthodont 2002;15:295–298.)
4HisashiKoshino, Toshihiro Hirai, Yuichi Yokoyama et al- Mandibular Residual Ridge Shape and the Masticatory Ability in Complete Denture Wearers ( J JpnProsthodontSoc 2008; 52:488-493.)
5Kapur K, Yurkstas A. Test foods for measuring masticatory performance of denture wearers.( J Prosthet Dent 1964;14:483–491.)
6Rendell J, Grasso JE, Gay T. Retention and stability of the maxillary denture during function.( J Prosthet Dent 1995;73:344–347.)
7Koshino H, Hirai T, Ishijima T, Ikeda Y. Tongue motor skills and masticatory performance in adult dentates, elderly dentates, and complete denture wearers.( J Prosthet Dent 1997;77:147–152.)
8Luthara S P, Measurement of area of maxillary basal seat for dentures.(J Prosthet Dent 1973;30:25-27.)
9. / Signature of the candidate
10 / Remarks of the guide / THIS THESIS WILL BE DONE UNDER MY GUIDANCE
11 / Name and designation( in block letters) of
11.1 Guide / DR. DEVIPRASAD NOOJI
READER
11.2 Signature
11.3 Co-Guide
11.4 Signature
11.5 Head of the department / PROF(DR.) PRANAV MODY
PROFESSOR AND HEAD OF THE DEPARTMENT
11.6 Signature
12 / 12.1 Remarks of the chairman and principal
12.2 Signature