RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES

KARNATAKA, BANGALORE.

ANNEXURE II

PROFORMA FOR REGISTRATION OF SUBJECT FOR DISSERTATION

1. / Name of the candidate and address (In block letters) / Dr. VENKATA SURESH V
NO 9, 2nd CROSS, 8th MAIN, SAPTAGIRI LAYOUT, THINDLU MAIN ROAD, VIDYARANYAPURA POST , BANGALORE 560097.
2. / Temporary address / NO 9, 2nd CROSS, 8th MAIN, SAPTAGIRI LAYOUT, THINDLU MAIN ROAD, VIDYARANYAPURA POST , BANGALORE 560097.
3. / Name of the institution / VOKKALIGARA SANGHA DENTAL COLLEGE AND HOSPITAL
4. / Course of the study and subject / Master of Dental Surgery (M.D.S.)
Department of Conservative dentistry and Endodontics
5. / Date of admission to course / 28/05/2011
6 / Title of the topic
THE EFFECT OF INSTRUMENT TYPE AND PREFLARING ON APICAL FILE SIZE DETERMINATION – AN IN VITRO STUDY

6. BRIEF RESUME OF THE INTENDED WORK

6.1  NEED FOR THE STUDY

Effective canal debridement relies on the accurate determination of the working length and adequate apical canal enlargement. The extent of apical enlargement is based on estimation of the initial canal size as determined by the size of hand file that binds at the working length (Grossman et al 1988 )[1]. Since the diameter of the apical canals vary greatly in all tooth groups, no standard size is advisable for the apical enlargement. One recommended approach is to enlarge the apical root canal to three sizes larger than the first file to bind[2].

If the Grossman criteria of enlarging a root canal to atleast three sizes beyond the first file that binds at working length is valid then one should question whether a standard master apical file size of 25 or 30 would be sufficient for apical preparation of narrow canals, as routinely recommended by most authors[1]. It may be more accurate to size each canal individually and subsequently determine the master apical file size to ensure that the apical third region is adequately enlarged and debrided prior to obturation [1].

Hence the purpose of this study is to determine whether the first file that binds at working length reflects the diameter of the canal.

6.2 REVIEW OF LITERATURE:

1) In this study one hundred and twenty one canals from 60 extracted intact human maxillary and mandibular premolars were utilized to determine the effect of instrument type ( k files and light speed instrument ) and the impact of preflaring on the first file size that binds at working length. It was concluded that pre flaring and hand held light speed instruments resulted in an increase in the instrument size that bound at working length. To determine an accurate master apical file size, canal orifice enlargement should be performed first before the placement of the assessment file[1].

2. In this study two similar groups (n=10) of mandibular premolars with curved canals were selected to determine, whether the first file to bind corresponds to the diameter of the canal in the apical region. It was concluded that, neither the first K file nor the first light speed instrument that bound at working length accurately reflected the diameter of the apical canal in curved mandibular premolars [2].

3. In this study 212 root canals were preflared from 80 extracted molars to establish a new approach for determination of the optimal apical preparation size. Working length was determined using electronic apex locator and special instruments specifically designed to measure the apical canal diameter were used. The special instruments had nontapered , noncutting shafts that allowed for better access in the apical region without binding in remote areas of the root canal. This study concluded that the optimal apical size preparation of the root canals should be shaped to larger sizes than normally recommended[3] .

4. In this study forty human lateral incisors with complete root formation were used to investigate the influence of cervical preflaring on determination of the initial apical file in maxillary lateral incisors. This study concluded that instrument binding technique for determining anatomical diameter at working length was not accurate. Preflaring of cervical and middle thirds of the root canal improved anatomical diameter determination, the instrument used for preflaring played a major role on determination of the anatomical diameter at the working length[4] .

5. In this study a total of 310 canals were evaluated in patients presenting for root canal therapy to compare sizes of the first instrument with or without a taper that binds at the apical constriction of a root canal after coronal flaring. This study concluded that the average size of first light speed to bind against the canal walls at the working length was approximately two ISO sizes larger than the first k file to bind (p<0.005). So one should consider introducing a nontapered instrument to working length after coronal flaring because determination of the initial apical canal diameter plays a major role in identifying the extent of final apical shaping [5].

6.3 OBJECTIVES OF THE STUDY:

1.To determine whether the first file that binds reflects the diameter of apical canal at the working length.

2. To determine the influence of cervical pre-flaring on the initial apical file size.

7.  MATERIALS AND METHODS:

7.1 SOURCE OF DATA

80 freshly extracted mandibular premolars from the department of Oral surgery, V. S Dental College and Hospital will be selected for this study.

INCLUSION CRITERIA

Teeth displaying normal pulp chambers, single root canal and fully formed apices.

EXCLUSION CRITERIA

Teeth with complicated anatomy, extreme root curvatures and root resorptions.

METHOD

Standard access to the pulp chambers will be performed and pulp tissue extripated with fine barbed broach, avoiding contact with root canal walls. A size 10 file will be inserted in to the canal until the tip of the file is visible at the apical foramen and the working length established by reducing 1 mm.

Thereafter, the teeth are randomly divided into 2 main groups with 40 samples in each group. The groups will be identified by labeling them as

group A (samples with cervical preflaring ) and group B (samples without cervical preflaring).

The samples in group A (samples with cervical preflaing) will be subdivided into 4 subgroups, with each group containing 10 samples. Initial apical file size is determined in each group with the following files,

GROUP 1- K file

GROUP 2 – Modified K file (1mm tip of the K file is removed )

GROUP 3 – Light speed

GROUP 4- Modified light speed (apical half of cutting head is removed)

The samples in group B (samples without cervical preflaring) will be subdivided into 4 sub groups, with each group containing 10 samples. Initial apical file size is determined the same way as group A.

The coronal aspect of each canal in group A will be flared using gates glidden drill size 50 (no 1) upto a depth where resistance is met, then sizes 70-110 ( nos 2-4) respectively to 1, 2, and 3mm shorter.

The canals will be irrigated with 2ml of 5.25% sodium hypochlorite after each gates glidden drill.

Initial apical file size for both group A and group B will be determined with manual k file and modified k file starting with 15 size , where as initial apical file size of light speed and modified light speed will be determined starting with smallest size (no 20). File sizes will be increased until a binding sensation is felt at the working length and the instrument size will be recorded for each tooth.

After apical file size determination for each tooth, the binding instrument will be fixed in the canal at working length with acrylic resin. The teeth will then be sectioned horizontally 1mm from the apex, with the binding file in fixed position. The root surfaces will then be stained with 2% methylene blue and observed under stereo microscope. Images obtained of the cut root surface will be captured. The analysis of the images will be carried out using Image Proexpress software.

Diameters of root canal and file will be recorded for each sample. The discrepancy between these diameters will be calculated (in mm) .

7.3 FOLLOW UP

Not relevant

7.4 STATISTICAL TESTS

The data collected will be subjected to statistical analysis. Two way ANOVA will be used to determine whether the first file that binds at working length reflects the diameter of the canal in the apical region and
the influence of preflaring on the initial apical file size.

7.5 Does the study require any investigation or intervention to be conducted on patients or other human or animal?

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7.4 ETHICAL CLEARENCE:

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8. LIST OF REFERENCES:

1. B. T. Tan and H. H Messer. The effect of instrument type and preflaring on apical file size determination. International journal of endodontics

(2002) , 35, 752-758

2. M.-K, Wu, D. Bakris , A. Roris , and P.R Wesselink. Does the first file to bind correspond to the diameter of the canal in the apical region. International journal of endodontics (2002) , 35, 264-267.

3. Roland Weiger, DMD, Tabor Bartha, DMD, Matthias Kalwitzki, DMD et al .A clinical method to determine the optimal apical preparation. Oral surg oral med oral path oral radiol endo (2006), 102, 686-691.

4) Guilherme Siqueira IBELLI, Juliana Machado BARROSSO, Alexander CAPELLI et al. Influence of cervical preflaring on apical file size determination in maxillary lateral incisors. Brazillian dental journal (2007), vol 18 (2 ), 430-435.

5) Sumeet Darda, Narendra Manwar, Manoj Chandak et al. An in vivo evaluation of two types of files used to accurately determine the diameter of the apical constriction of a root canal: An in vivo study. Journal of contemporary dental practice(2009), vol 10, no 4.

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9. SIGNATURE OF THE CANDIDATE
10. REMARKS OF THE GUIDE / This study has important clinical relevance as it will determine whether cervical preflaring and type of instrument will help assess the initial apical file size.
11.NAME AND DESIGNATION OF GUIDE (IN BLOCK LETTERS) / DR. USHA H.L
PROFESSOR & HEAD
DEPARTMENT CONSERVATIVE DENTISTRY & ENDODONTICS
V.S DENTAL COLLEGE & HOSPITAL
K.R ROAD, V.V PURAM,
BANGALORE-560 004
11.1 SIGNATURE
11.2 CO-GUIDE IF ANY
11.3 SIGNATURE
11.4 HEAD OF THE DEPARTMENT / DR. USHA H.L
V.S DENTAL COLLEGE & HOSPITAL
K.R ROAD, V.V PURAM,
BANGALORE-560 004
11.5 SIGNATURE
12.1 REMARKS OF THE CHAIRMAN AND PRINCIPAL
12.2 SIGNATURE

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