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RS 37 Comparison of ultrasonic and high-speed root-end preparations using matched teeth
A n a l y s i s of F a c t o r s A f f e c t i n g C h a n g e s in Lesion Size F o l l o w i n g Apicoectomy. Shuler, Scott E.* and Green, D.B., U n i v e r s i t y of Louisville.
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The treatment records of 509 p a t i e n t s who had undergone apicoectomy in the postgraduate endodontic program of the University of Louisville were r e t r o s p e c t i v e l y reviewed, and data r e g a r d i n g certain descriptive and peri-operative factors were tabulated and analyzed. The 269 cases with f o l l o w - u p data of at least six months were assessed for changes in lesion size and significant correlations were sought to any of these factors. It was found that 84.0% of r a d i o g r a p h i c lesions were smaller at recall. 8.8% were lar~er, and 7.4% showed no ehan~e in size, S i g n i f i c a n t r e l a t i o n s h i p s (P<.05) were found when chanae in lesion size was analyzed w i t h respect to the restorative status of the tooth at the recall appointment, the length of the recall interval, and whether there were symptoms at the t i m e of the recall. There was no statistieallv si~nifiean~ correlation between ehan~e in lesion size and any other factor.
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Comparison of Ultrasonic and High-speed Root-End Preparations Using Matched Teeth. D.S. Mehlhaff*, J.G. Marshall, J.C. Baumgartner Oregon Health Sciences University, Portland, OR The purpose of this study was to compare ultrasonic and highspeed handpiece root-end preparations. One hundred forty-four roots from 58 bilaterally matched pairs of human cadaver teeth (anterior-22, premolar-22, molar-14) were used in this study and divided into two experimental groups. The teeth were prepared and the amalgam root-end f'tUing placed while the teeth remained in the cadavers. In group 1 ultrasonic preparations were made in 72 roots. Ultrasonic preparations were made with CT-5 and CT-1 tips using an EIE piezoelectric unit. In group 2 high-speed handpiece preparations were made in 72 roots. A size 1/2 long shank round bur was used for high-speed root-end preparations which were confined to the resected root surface. After the size of the bony crypt was measured, the teeth were extracted and radiographed from both the MD & BL directions. None of the 144 preparations resulted in root perforation. The incidence of ultrasonic root-end preparations deviating from the canal spaces was found to be 11.1% (8/72). Bur preparations routinely deviated from the canal space. The average MD minimum depths of ultrasonic vs. high-speed preparations were 2.05 mm and 1.61 mm, respectively (p<0.0001). The average BL minimum depth of preparation was 2.23 mm for the ultrasonic and 1.95 mm for the high-speed preparations (p=0.0003). A significantly greater bevel angle was required for the bur preparations, 31.1 ° versus 15.4 ° for the ultrasonic preparations (p<0.0001). The bony crypt size required for bur preparations was significantly greater than that for ultrasonic preparations. In the vertical direction, the bur preparations averaged 6.9 mm versus 5.5 mm for the ultrasonic (p<0.0001). In the horizontal direction, the bur preparations averaged 5.3 mm versus 4.9 mm (p--0.008). Ultrasonic root-end nreoarations were considered suoerior within the narameters o(th-i~ ~'tudy,
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224
The Canal Isthmus in Mesiobuccal Roots of Maxillary First Molars. R.N. Weller*, S.P. Niemczyk, and S. Kim. Medical College of Georgia, Augusta, GA and University of Pennsylvania, Philadelphia, PA. The success rate of surgical endodontics in posterior teeth is often less than in anterior teeth. The maxillary first molar and in particular the mesiobuccal root is frequently treated surgically. However, the successful healing of this root is lower than other teeth. A factor which should be considered is the canal isthmus. The purpose of this study was to determine the incidence, type and location of the root canal isthmus. The mesiobuccal crown and root were resected in toto frorr fifty maxillary left and right first molars. The opening into the pulp chamber was sealed with wax and each root was embedded in clear resin. Starting at the root apex, six 1 mm thick sections were made perpendicular to the long axis of the root with a low-speed diamond saw. Each section was placed into 5.25% sodium hypochlorite, rinsed and dried. The apical side of each section was stained with 2 % methylene blue dye and videotaped With an operating microscope at x32 magnification. The number of root canals present and the presence or absence of an isthmus was determined. The isthmus was classified as complete or partial. The results indicated that 60% of the roots had two canals present. For those sections with two canals, the incidence of an isthmus, either complete or partial, was 91% and was highest in the q to 5 mm sections. The 4 mm sections had an isthmus pre~ent 100% of the time. When the mesiobuccal root is resected, an isthmus should be considered to be present and treated.
Preparation of Root End Resin Replicas for SEM Examination B Van Mierlo*, H Abedi, M Torabinejad, Loma Linda University, Loma Linda, California. The scanning Electron Microscope (SEM) has been used in Endodontics to examine the adaptation of various root end filling materials. SEM specimen preparation induces artifacts such as cracks, gap formation, and shrinkage. Creating resin replicas of the specimen to be examined avoids introduction of these artifacts. The purpose of this study was to describe a step-by-step technique for resin replica formation. Forty-seven extracted single-rooted human teeth were cleaned, shaped, and obturated with gutta-percha. The crowns were removed at the CEJ and the root-ends resected to a standardized size. The coronal end of the remaining root was mounted on baseplate wax. Impressions of the resected root-ends were taken following cavity preparation and placement of the root-end filling. The impressions were poured in epoxy resin and the resultant replicas, along with the original specimen, were prepared for SEM examination. Comparincl photomicrographs of oriclinal samples with those of the resin replicas demonstrates that preparation of teeth for SEM examination induces many artifacts which may influence the examiner's observations. The use of resin replicas minimizes the introduction of artifacts and provides an accurate reproduction of the specimen.
r~RIR.~ffl
The treatment records of 509 p a t i e n t s who had undergone apicoectomy in the postgraduate endodontic program of the University of Louisville were r e t r o s p e c t i v e l y reviewed, and data r e g a r d i n g certain descriptive and peri-operative factors were tabulated and analyzed. The 269 cases with f o l l o w - u p data of at least six months were assessed for changes in lesion size and significant correlations were sought to any of these factors. It was found that 84.0% of r a d i o g r a p h i c lesions were smaller at recall. 8.8% were lar~er, and 7.4% showed no ehan~e in size, S i g n i f i c a n t r e l a t i o n s h i p s (P<.05) were found when chanae in lesion size was analyzed w i t h respect to the restorative status of the tooth at the recall appointment, the length of the recall interval, and whether there were symptoms at the t i m e of the recall. There was no statistieallv si~nifiean~ correlation between ehan~e in lesion size and any other factor.
I:IRIRq7 I
Comparison of Ultrasonic and High-speed Root-End Preparations Using Matched Teeth. D.S. Mehlhaff*, J.G. Marshall, J.C. Baumgartner Oregon Health Sciences University, Portland, OR The purpose of this study was to compare ultrasonic and highspeed handpiece root-end preparations. One hundred forty-four roots from 58 bilaterally matched pairs of human cadaver teeth (anterior-22, premolar-22, molar-14) were used in this study and divided into two experimental groups. The teeth were prepared and the amalgam root-end f'tUing placed while the teeth remained in the cadavers. In group 1 ultrasonic preparations were made in 72 roots. Ultrasonic preparations were made with CT-5 and CT-1 tips using an EIE piezoelectric unit. In group 2 high-speed handpiece preparations were made in 72 roots. A size 1/2 long shank round bur was used for high-speed root-end preparations which were confined to the resected root surface. After the size of the bony crypt was measured, the teeth were extracted and radiographed from both the MD & BL directions. None of the 144 preparations resulted in root perforation. The incidence of ultrasonic root-end preparations deviating from the canal spaces was found to be 11.1% (8/72). Bur preparations routinely deviated from the canal space. The average MD minimum depths of ultrasonic vs. high-speed preparations were 2.05 mm and 1.61 mm, respectively (p<0.0001). The average BL minimum depth of preparation was 2.23 mm for the ultrasonic and 1.95 mm for the high-speed preparations (p=0.0003). A significantly greater bevel angle was required for the bur preparations, 31.1 ° versus 15.4 ° for the ultrasonic preparations (p<0.0001). The bony crypt size required for bur preparations was significantly greater than that for ultrasonic preparations. In the vertical direction, the bur preparations averaged 6.9 mm versus 5.5 mm for the ultrasonic (p<0.0001). In the horizontal direction, the bur preparations averaged 5.3 mm versus 4.9 mm (p--0.008). Ultrasonic root-end nreoarations were considered suoerior within the narameters o(th-i~ ~'tudy,
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I
224
The Canal Isthmus in Mesiobuccal Roots of Maxillary First Molars. R.N. Weller*, S.P. Niemczyk, and S. Kim. Medical College of Georgia, Augusta, GA and University of Pennsylvania, Philadelphia, PA. The success rate of surgical endodontics in posterior teeth is often less than in anterior teeth. The maxillary first molar and in particular the mesiobuccal root is frequently treated surgically. However, the successful healing of this root is lower than other teeth. A factor which should be considered is the canal isthmus. The purpose of this study was to determine the incidence, type and location of the root canal isthmus. The mesiobuccal crown and root were resected in toto frorr fifty maxillary left and right first molars. The opening into the pulp chamber was sealed with wax and each root was embedded in clear resin. Starting at the root apex, six 1 mm thick sections were made perpendicular to the long axis of the root with a low-speed diamond saw. Each section was placed into 5.25% sodium hypochlorite, rinsed and dried. The apical side of each section was stained with 2 % methylene blue dye and videotaped With an operating microscope at x32 magnification. The number of root canals present and the presence or absence of an isthmus was determined. The isthmus was classified as complete or partial. The results indicated that 60% of the roots had two canals present. For those sections with two canals, the incidence of an isthmus, either complete or partial, was 91% and was highest in the q to 5 mm sections. The 4 mm sections had an isthmus pre~ent 100% of the time. When the mesiobuccal root is resected, an isthmus should be considered to be present and treated.
Preparation of Root End Resin Replicas for SEM Examination B Van Mierlo*, H Abedi, M Torabinejad, Loma Linda University, Loma Linda, California. The scanning Electron Microscope (SEM) has been used in Endodontics to examine the adaptation of various root end filling materials. SEM specimen preparation induces artifacts such as cracks, gap formation, and shrinkage. Creating resin replicas of the specimen to be examined avoids introduction of these artifacts. The purpose of this study was to describe a step-by-step technique for resin replica formation. Forty-seven extracted single-rooted human teeth were cleaned, shaped, and obturated with gutta-percha. The crowns were removed at the CEJ and the root-ends resected to a standardized size. The coronal end of the remaining root was mounted on baseplate wax. Impressions of the resected root-ends were taken following cavity preparation and placement of the root-end filling. The impressions were poured in epoxy resin and the resultant replicas, along with the original specimen, were prepared for SEM examination. Comparincl photomicrographs of oriclinal samples with those of the resin replicas demonstrates that preparation of teeth for SEM examination induces many artifacts which may influence the examiner's observations. The use of resin replicas minimizes the introduction of artifacts and provides an accurate reproduction of the specimen.