Brief Resume Of Intended Work
6.1 NEED FOR THE STUDY:
Over years, occlusal analysis had been a matter of guess work. Aids such as articulating paper, waxes , pressure indicating paste were used when the dentist has to assess and balance the occlusal forces. Most of these measures are not sensitive enough to detect contact, time and amount of occlusal load simultaneously.
T –scan system is a new computerized device that uses time as diagnostic variable to quantify occlusal contact information . The purpose of this study is to determine if a relationship exists between the occlusal load applied to metal dies and size of the markings produced from tooth contact when a clinically used dental articulating paper and T-scan is interposed alternatively.
6.2 REVIEW OF LITERATURE:
A study was conducted to determine if a relationship exists between the occlusal load applied to non-wearing epoxy casts and the size of the markings produced from tooth contact when a clinically used dental articulating paper is interposed . The experiment was carried out with a uniaxial testing machine repeatedly. A compressive load, beginning at 25N and incrementally continuing upto 450N ,to a pair of epoxy dental casts with articulating paper interposed. The resultant paper marking were photographed and analysed using photographic image analysis and sketching program. Graphical interpretation of the data indicated that the mark area increased non- linearly with increasing load. When the data was grouped to compare consistency of the mark area between teeth, a high variability of mark area was observed between different teeth at the same applied load. No direct relationship between paper mark area and applied load could be found.1
A study was conducted to measure bilateral simultaneous occlusal contact with computer-analysed and guided occlusal adjustments. The author concluded that computerized occlusal analysis showed true bilateral occlusal contact time simultaneous whereas, articulating paper labelling was an inadequate indicator of perceived occlusal contact time simultaneity as it renders no occlusal contact force or time sequencing. When occlusal adjustments was guided by computerized occlusal analysis, occlusal contact on all potentially occluding teeth could be approximated to occur within 0.2 second.2
A study was conducted on the occlusal registration strip. The purpose of this study was to determine the thickness, strength, and plastic deformation of selected occlusal registration strips. There was significant differences in the thickness , strength , and plastic deformation of the various articulating papers and occlusal registration strips used. The patient’s perception of occlusal thickness ranges from 12.5 to 100 µm .Hence, the author concluded that the occlusal registration strip should be less than 21µm thick and should possess plastic deformation.3
A study was conducted to determine the linear relationship between strip thickness and area of marks. The author concluded that the thicker the strip , the larger the mark . Red papers register larger marks than registration strips of similar thickness, while the thinnest registration material ,mylar plastic strips , produced smaller marksthan papers.4
A study was conducted to determine the bite force and state of dentition in males and females. In males the maximal bite force measured in the molar region was 39 kg (382 N) AND 18 KG (176 N) in the incisor region .The corresponding values for the females were 22kg (216 N) and 11kg (108 ) .The average difference in the bite force between the men and women was larger in the group with natural teeth than in the one with complete dentures .In both sexes the bite force was notably smaller among the denture wearers than among the dentate persons. The number of natural teeth varied closely with the bite force. The greater number of natural teeth the greater the bite force.5
6.3 OBJECTIVES OF THE STUDY:
- To compare the relationship between the (1) occlusal load and articulating paper and (2) occlusal load and T-scan and (3) to determine which is a more accurate occlusal indicator among articulating paper and T-scan.
MATERIALS AND METHODS:
(1)a metal jig to which a load cell of capacity 100 kg is attached.
(2)metal dentulous casts (maxillary and mandibular).
(3)Articulating paper-Bausch thickness of 0.04mm,
(4)T-scan lll -sensor of thickness 0.1mm.
T-Scan is a reliable and easy-to-use clinical diagnostic device that senses and analyses occlusal contact forces using paper-thin, disposable sensors6.The T-Scan III system comes with a full-featured Patient File Management system, which makes storing patient records and tracking occlusal recordings simple, and makes the system an integral component of the clinical workstation for occlusal diagnosis and treatment
The T-scan system is composed of a sensor, handle and cable, system unit, and software.The T-Scan III sensor is an ultra-thin (.004", 0.1 mm), flexible printed circuit that detects patient’s occlusal forces. The USB Handle gathers the data from the sensor and processes it so that it can be sent easily to the computer. The handle’s attached USB cable is then connected directly to the computer via the USB port.7The system unit contains the electronics for recording, analysing and viewing occlusaldata.The real time display and record mode is used to gather occlusal data. Initially, the monitor displays the tooth contacts as they are occurring in real time.This displays compares occlusal contact patterns7.
The metal casts is vertically loaded to the metal jig and rigidly anchored during all cast intercuspating test. Preliminary loading of casts were performed once to properly mate the casts and to secondly ensure that the overshoot of load cell was an acceptable values. Then, the articulating paper thickness of 0.04mm, red surface occluding the maxillary cast and blue surface occluding the mandibular cast are placed between the casts . The loading began before the dies were intercuspated until complete intercuspation at 25N loads. The readings on the displaying unit was recorded before returning to zero position, to release the load. This procedure was repeated twice more, each 3-tap trial comprised one test. Now, the paper markings left on the maxillary and mandibular casts are photographed with a 10 megapixel digital camera. Next, T-scan lll is occluded between the metal die and the force is loaded and recorded. Now, the paper markings and T-scan graphical presentation are compared.The load was then increased 25-50N, and the entire process was repeated within, occlusal force range and the casts were loaded at 25N, 50N, 100N, 150N, 200N, 250N, 300N, 350N, 400N and 450N.
The experimental design produced 100 photos for analysis. In all photographs,6 consistent markings (indicating 6 contacts) were identified on both casts. Any other inconsistent occlusal markings were disregarded. The 12 distinct contact markings were analysed using MOTIC software to magnify the markings. The markings were analysed sequentially: from contact numbers 1-6. A total of 600
(12 teeth x 10 force levels x 3 repetitions =300) marks were statistically analysed.
1)a metal jig to which a load cell of capacity 100 kg is attached
(2)metal dentulous casts (maxillary and mandibular).
(3)Articulating paper-Bausch thickness of 0.04mm
(4)T-scan lll -sensor of thickness 0.1mm
7.3 Does the study require any investigation or intervention to be
conductedon patients or other humans or animals?
7.4 Has ethical clearance been obtained from your institution
LIST OF REFERENCES:
1.Carey, Mark Craig, Robert B Kerstein and John Radke : Determining a Relationship Between Applied Occlusal Load and Articulating Paper Mark Area. The Open Dentistry Journal,2007; 1: 1-7.
2.Robert B Kerstein, Ken Grundset, : Obtaining measurable bilateral simultaneous occlusal contacts with computer-analyzed and guided occlusal adjustments.Quintessence International,2001;32:7-18.
3.Gail. C .Halperin, Alexander R.Halperin, Barry K.Norling: Thickness, strength, and plastic deformation of occlusal registration strips, J ProsthetDent 1982;48:575-578.
4.ErnstSchelb,, David A.Kaiser, Charles E.Brukl,Ph.D:Thickness and marking characteristics of occlusal registration strips. J Prosthet Dent 1985;54:122-126.
5.EvaHelkimo, Gunnar E.Carlsson and MarttiHelkimo: Bite force and state of dentition, ActaOdont ,1976; 35;297-303.
6.William L ,Maness,, Robert Podoloff,,: Distribution of occlusal contacts in maximum intercuspation, J Prosthet Dent 1989;62:238-242.