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PR 26 Permeability of sealed and unsealed bevel preparations
Journal of Endodontics 41,213
Vol. 22, No. 4, April 1996
-,IpvNI
C o m p a r i s o n of Two I n s t r u m e n t a t i o n Techniques to P r e p a r e S i m u l a t e d C u r v e d Canals, C.R. CARR*, B.P. A U S T I N , H.D. WALIA, K.L. ZAKARIASEN, M U S O D , Milwaukee, W I Kerr r e c e n t l y introduced the M-4 handpiece to facilitate in t h e i n s t r u m e n t a t i o n of root canals. The p u r p o s e of this s t u d y w a s to c o m p a r e t h e t i m e i t took to p r e p a r e the a p i c a l o n e - t h i r d of c a n a l s u s i n g a w a v i a n m o t i o n h a n d technique versus u s i n g files in the M-4 handpiece. An e v a l u a t i o n of p r e p a r a t i o n q u a l i t y w a s done b l i n d l y b y 2 o t h e r clinicians. A t o t a l of t e n plastic blocks were i n s t r u m e n t e d w i t h e a c h t e c h n i q u e . K-flex files were used for b o t h groups. W o r k i n g l e n g t h was e s t a b l i s h e d in both g r o u p s with a size 20 file, t h e n the coronal onehalf was flared with 2, 3 a n d 4 G a t e Glidden drills. Only t h e t i m e i t took to i n c r e a s e t h e m a s t e r a p i c a l file to a size 30 a n d s t e p b a c k i n o n e - h a l f m m i n c r e m e n t s to a size 50 w a s recorded. P r e a n d p o s t i n s t r u m e n t a t i o n pictures were t a k e n of t h e blocks. T h e s e were placed in a s c a n n e r a n d a c o m p u t e r i m a g e was u s e d to e v a l u a t e a n y c h a n g e in t h e s h a p e of t h e p r e p a r a t i o n s . The p r e p a r a t i o n s were j u d g e d u n a c c e p t a b l e if any ledging or t r a n s p o r t a t i o n occurred t h a t d i d not allow a r e t u r n to the original apex. T h e m e a n t i m e for h a n d i n s t r u m e n t a t i o n w a s 147.5_+28.3 seconds a n d for t h e M-4 i n s t r u m e n t a t i o n m e a n t i m e w a s 1 9 4 + 3 0 . 7 7 9 seconds. T h e r e s u l t s of t h i s s t u d y d e m o n s t r a t e d t h a t h a n d filing w a s s i g n i f i c a n t l v (.01 level of confidence s t u d e n t ' s t - t e s t ) f a s t e r w i t h no significant difference in ~h¢ a u a l i t v of o r e o a r a t i o n s . A l t e r n a t e filing orotocols m a y m a k e use o f the M-4 h a n d p i e c e more efficient.
Timing of Restoration as a Risk Factor for Endodontic Outcome. N. CHUGAL*, J. CLIVE, L. SPANGBERG. University of Connecticut, School of Dental Medicine, Farmington, CT. Conventional clinical practice dictates that endodontically treated teeth are restored following the completion ofendodontic therapy. Teleologically, it appears protective to have a permanent restoration placed as soon as possible after the treatment completion. Unprotected tooth structure is vulnerable to re-contamination and re-infection as many coronal leakage studies have suggested. The purpose of this study was to evaluate the effect of the time of placement of permanent restoration on long-term endodontic treatment outcome. In this retrospective cohort study, 200 teeth were evaluated at 3.5-4 year recall. The results indicate nearly 50% failure rate for non-restored teeth, whereas teeth restored with permanent restoration had 18% failure rate across all diagnostic categories (p<0.001). With increased time span between endodontic treatment completion and placement of permanent restoration, this effect becomes augmented. This finding has biological basis. Initial healing (i.e. success) can be ascribed to decreased infection (i.e. endodontic therapy). Long-term healing however, is due to the combined effect of endodontic therapy and subsequent restorative experience. Lo~stic regession model suggests strong interaction between the combined effects ofendodontic theranv and subsenuent restorative ext~erience. The nature, dynamics, and magnitude of that interaction is oresented. Supported in part by the Office of Academic Affairs, Veterans Administration, Washington, DC.
PRIP2_~J
PR]p,.~,]
P e r m e a b i l i t y of S e a l e d a n d U n s e a l e d Bevel P r e p a r a t i o n s , M.E. SILVER, B.P. A U S T I N , H.D. WALIA, J.D. DEGUZMAN*, MUSOD, Milwaukee, W I E s t a b l i s h m e n t of a f l u i d - r e s i s t a n t seal is t h o u g h t to improve the prognosis of retrofillings. Our previous studies d e m o n s t r a t e d t h a t l e a k a g e t h r o u g h retroffllings in e x t r a c t e d t e e t h w a s a l w a y s significantly g r e a t e r t h a n t h a t t h r o u g h retrofillings in s i m u l a t e d c a n a l s in acrylic blocks. This s u g g e s t e d t h a t fluid p e r c o l a t i o n t h r o u g h d e n t i n a l t u b u l e s c o u l d c o n t r i b u t e to t h e o b s e r v e d m i c r o l e a k a g e . T h e p u r p o s e of t h i s s t u d y w a s to e v a l u a t e t h e effect of s e a l i n g t h e b e v e l e d s u r f a c e of r e t r o f i l l i n g p r e p a r a t i o n s . C a n a l s of 140 e x t r a c t e d , single rooted h u m a n t e e t h were p r e p a r e d to a size 110 M A F a n d 45 degree bevels were p l a c e d in t h e apical 1/3 of each. D i a k e t , E B A a n d IRM w e r e condensed into t h e 20 t e e t h e a c h w i t h l m m p r e p a r a t i o n s a n d 20 t e e t h each with 3ram preparations. Twenty teeth were controls. H a l f of t h e e x p e r i m e n t a l t e e t h in each group h a d t h e bevels s e a l e d w i t h 3 l a y e r s of nail polish a n d 2 l a y e r s of b e e s w a x a p p l i e d u s i n g 3.5x m a g n i f i c a t i o n . M i c r o l e a k a g e w a s m o n i t o r e d e v e r y 24 h o u r s for 30 consecutive d a y s u s i n g t h e e l e c t r o c h e m i c a l technique. There was significantly less l e a k a g e in teeth with sealed bevels in t h e following g r o u p s : l m m t h i c k IRM, 3 m m t h i c k IRM, l m m t h i c k EBA. T h e 3 o t h e r g r o u p s w i t h sealed bevels demonstrated greater leakage. The r e s u l t s of t h i s s t u d v i n d i c a t e t h a t s e a l i n g t h e b e v e l e d surface u n d e r i d e a l d r y conditions did not o r e d i c t a b l v improve t h e anival ~eal of retrofillings.
Determining the Location of Horizontal Root Fractures With Apex Locators. JR DOW*, JB GOESSMAN*, & NJ MCDONALD. University of Maryland Dental School, Baltimore, Maryland, USA
The current generation of apex Iocators have been shown to be 83-93% accurate in determining working length. The Root ZX and Neosono MC* are examples of current generation devices and operate by frequency ratios and resistance, respectively. The purpose of lhisstudy was to evaluate the Root ZX and Neosono MC* apex locators in determining the coronal edge of horizontal root fractures. 10extracted single rooted teeth were accessed and the roots were fractured using Vice Grips. Fractured roots were reattached with sticky wax and placed in irreversible alginate to the level of the CEJ. Tap water was placed in the access cavity and dried with compressed air. A #10, 15 or 20 file was placed in the canal until the locator indicated the fracture or until the apical constriction was reached, The working length was measured to the nearest 0.Smm and radiographs were taken. Both locators were used with each tooth and the order of use was alternated for subsequent teeth. The teeth were removed from thealginate, separated,and photographs taken of the coronal portion of the fracture with the file in place. If the file was not visible, it was moved apically until visible. The working length was considered accurate if the file moved apically 0.5 mm or less prior to being visible. The data were analyzed using Kruskal-Wallis l-way ANOVA. Neosono MC* Root ZX Flush 6 7 Short 2 0 Long 2 3 There was no statistical difference between the Neosono MC* and Root ZX in determining the coronal edge of the root fracture(Chisquare=0.3 p>0.05). The results indicated that apex locators may be provide the clinician with an accurate method for determining the coronal most portion of horizontal root fractures.
Vol. 22, No. 4, April 1996
-,IpvNI
C o m p a r i s o n of Two I n s t r u m e n t a t i o n Techniques to P r e p a r e S i m u l a t e d C u r v e d Canals, C.R. CARR*, B.P. A U S T I N , H.D. WALIA, K.L. ZAKARIASEN, M U S O D , Milwaukee, W I Kerr r e c e n t l y introduced the M-4 handpiece to facilitate in t h e i n s t r u m e n t a t i o n of root canals. The p u r p o s e of this s t u d y w a s to c o m p a r e t h e t i m e i t took to p r e p a r e the a p i c a l o n e - t h i r d of c a n a l s u s i n g a w a v i a n m o t i o n h a n d technique versus u s i n g files in the M-4 handpiece. An e v a l u a t i o n of p r e p a r a t i o n q u a l i t y w a s done b l i n d l y b y 2 o t h e r clinicians. A t o t a l of t e n plastic blocks were i n s t r u m e n t e d w i t h e a c h t e c h n i q u e . K-flex files were used for b o t h groups. W o r k i n g l e n g t h was e s t a b l i s h e d in both g r o u p s with a size 20 file, t h e n the coronal onehalf was flared with 2, 3 a n d 4 G a t e Glidden drills. Only t h e t i m e i t took to i n c r e a s e t h e m a s t e r a p i c a l file to a size 30 a n d s t e p b a c k i n o n e - h a l f m m i n c r e m e n t s to a size 50 w a s recorded. P r e a n d p o s t i n s t r u m e n t a t i o n pictures were t a k e n of t h e blocks. T h e s e were placed in a s c a n n e r a n d a c o m p u t e r i m a g e was u s e d to e v a l u a t e a n y c h a n g e in t h e s h a p e of t h e p r e p a r a t i o n s . The p r e p a r a t i o n s were j u d g e d u n a c c e p t a b l e if any ledging or t r a n s p o r t a t i o n occurred t h a t d i d not allow a r e t u r n to the original apex. T h e m e a n t i m e for h a n d i n s t r u m e n t a t i o n w a s 147.5_+28.3 seconds a n d for t h e M-4 i n s t r u m e n t a t i o n m e a n t i m e w a s 1 9 4 + 3 0 . 7 7 9 seconds. T h e r e s u l t s of t h i s s t u d y d e m o n s t r a t e d t h a t h a n d filing w a s s i g n i f i c a n t l v (.01 level of confidence s t u d e n t ' s t - t e s t ) f a s t e r w i t h no significant difference in ~h¢ a u a l i t v of o r e o a r a t i o n s . A l t e r n a t e filing orotocols m a y m a k e use o f the M-4 h a n d p i e c e more efficient.
Timing of Restoration as a Risk Factor for Endodontic Outcome. N. CHUGAL*, J. CLIVE, L. SPANGBERG. University of Connecticut, School of Dental Medicine, Farmington, CT. Conventional clinical practice dictates that endodontically treated teeth are restored following the completion ofendodontic therapy. Teleologically, it appears protective to have a permanent restoration placed as soon as possible after the treatment completion. Unprotected tooth structure is vulnerable to re-contamination and re-infection as many coronal leakage studies have suggested. The purpose of this study was to evaluate the effect of the time of placement of permanent restoration on long-term endodontic treatment outcome. In this retrospective cohort study, 200 teeth were evaluated at 3.5-4 year recall. The results indicate nearly 50% failure rate for non-restored teeth, whereas teeth restored with permanent restoration had 18% failure rate across all diagnostic categories (p<0.001). With increased time span between endodontic treatment completion and placement of permanent restoration, this effect becomes augmented. This finding has biological basis. Initial healing (i.e. success) can be ascribed to decreased infection (i.e. endodontic therapy). Long-term healing however, is due to the combined effect of endodontic therapy and subsequent restorative experience. Lo~stic regession model suggests strong interaction between the combined effects ofendodontic theranv and subsenuent restorative ext~erience. The nature, dynamics, and magnitude of that interaction is oresented. Supported in part by the Office of Academic Affairs, Veterans Administration, Washington, DC.
PRIP2_~J
PR]p,.~,]
P e r m e a b i l i t y of S e a l e d a n d U n s e a l e d Bevel P r e p a r a t i o n s , M.E. SILVER, B.P. A U S T I N , H.D. WALIA, J.D. DEGUZMAN*, MUSOD, Milwaukee, W I E s t a b l i s h m e n t of a f l u i d - r e s i s t a n t seal is t h o u g h t to improve the prognosis of retrofillings. Our previous studies d e m o n s t r a t e d t h a t l e a k a g e t h r o u g h retroffllings in e x t r a c t e d t e e t h w a s a l w a y s significantly g r e a t e r t h a n t h a t t h r o u g h retrofillings in s i m u l a t e d c a n a l s in acrylic blocks. This s u g g e s t e d t h a t fluid p e r c o l a t i o n t h r o u g h d e n t i n a l t u b u l e s c o u l d c o n t r i b u t e to t h e o b s e r v e d m i c r o l e a k a g e . T h e p u r p o s e of t h i s s t u d y w a s to e v a l u a t e t h e effect of s e a l i n g t h e b e v e l e d s u r f a c e of r e t r o f i l l i n g p r e p a r a t i o n s . C a n a l s of 140 e x t r a c t e d , single rooted h u m a n t e e t h were p r e p a r e d to a size 110 M A F a n d 45 degree bevels were p l a c e d in t h e apical 1/3 of each. D i a k e t , E B A a n d IRM w e r e condensed into t h e 20 t e e t h e a c h w i t h l m m p r e p a r a t i o n s a n d 20 t e e t h each with 3ram preparations. Twenty teeth were controls. H a l f of t h e e x p e r i m e n t a l t e e t h in each group h a d t h e bevels s e a l e d w i t h 3 l a y e r s of nail polish a n d 2 l a y e r s of b e e s w a x a p p l i e d u s i n g 3.5x m a g n i f i c a t i o n . M i c r o l e a k a g e w a s m o n i t o r e d e v e r y 24 h o u r s for 30 consecutive d a y s u s i n g t h e e l e c t r o c h e m i c a l technique. There was significantly less l e a k a g e in teeth with sealed bevels in t h e following g r o u p s : l m m t h i c k IRM, 3 m m t h i c k IRM, l m m t h i c k EBA. T h e 3 o t h e r g r o u p s w i t h sealed bevels demonstrated greater leakage. The r e s u l t s of t h i s s t u d v i n d i c a t e t h a t s e a l i n g t h e b e v e l e d surface u n d e r i d e a l d r y conditions did not o r e d i c t a b l v improve t h e anival ~eal of retrofillings.
Determining the Location of Horizontal Root Fractures With Apex Locators. JR DOW*, JB GOESSMAN*, & NJ MCDONALD. University of Maryland Dental School, Baltimore, Maryland, USA
The current generation of apex Iocators have been shown to be 83-93% accurate in determining working length. The Root ZX and Neosono MC* are examples of current generation devices and operate by frequency ratios and resistance, respectively. The purpose of lhisstudy was to evaluate the Root ZX and Neosono MC* apex locators in determining the coronal edge of horizontal root fractures. 10extracted single rooted teeth were accessed and the roots were fractured using Vice Grips. Fractured roots were reattached with sticky wax and placed in irreversible alginate to the level of the CEJ. Tap water was placed in the access cavity and dried with compressed air. A #10, 15 or 20 file was placed in the canal until the locator indicated the fracture or until the apical constriction was reached, The working length was measured to the nearest 0.Smm and radiographs were taken. Both locators were used with each tooth and the order of use was alternated for subsequent teeth. The teeth were removed from thealginate, separated,and photographs taken of the coronal portion of the fracture with the file in place. If the file was not visible, it was moved apically until visible. The working length was considered accurate if the file moved apically 0.5 mm or less prior to being visible. The data were analyzed using Kruskal-Wallis l-way ANOVA. Neosono MC* Root ZX Flush 6 7 Short 2 0 Long 2 3 There was no statistical difference between the Neosono MC* and Root ZX in determining the coronal edge of the root fracture(Chisquare=0.3 p>0.05). The results indicated that apex locators may be provide the clinician with an accurate method for determining the coronal most portion of horizontal root fractures.