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Abstracts 2 - Endodontics
Healing of apical periodontitis after endodontic treatment with and without obturation in dogs. An SEM study of the effects of different irrigation sequences and ultrasonics. Smear layer removal capacity of disinfectant solutions used with and without EDTA A scanning electron microscopic evaluation of different root canal irrigation regimens Bacteriologic investigation of the effects of sodium hypochlorite Killing of Enterococcus faecalis by MTAD and chlorhexidine digluconate Bacteriologic investigation of the effects of sodium hypochlorite What are the longevities of teeth and oral implants? The Impact of Instrument Fracture on Outcome of Endodontic Treatment. Comparisons of bacterial patterns present at implant and tooth sites Dental implants placed in expanded narrow edentulous ridges Comparison of bacterial plaque samples from titanium implant and tooth surfaces by different methods Fracture Resistance of Human Root Dentin Exposed to Intracanal Calcium Hydroxide Does Hybridization of Intraradicular Dentin Really Improve Fiber Post Retention Healing of apical periodontitis after endodontic treatment with and without obturation in dogs. 1: J Endod. 2006 Jul;32(7):628-33. Epub 2006 May 2. Sabeti MA, Nekofar M, Motahhary P, Ghandi M, Simon JH. Department of Endodontics, University of Southern California, Los Angeles, 90089-0641, USA. sabeti2001@yahoo.com The principle of obturation of the root canal space is generally accepted. This belief has dominated the field of endodontics despite the absence of credible scientific evidence. Little information is available on the possible relationships between endodontic success and obturation of the root canal system. The present study compares the healing of instrumented and obturated versus instrumented and nonobturated root canal systems with apical periodontitis. Fifty-six root canals in 28 third and fourth bilateral lower premolar teeth with completely formed apices in seven mixed German Shepherd dogs were used. Apical lesions were created by accessing the canals, removing the pulp and leaving them open to the oral environment for 42 days. The teeth in the control group were instrumented, irrigated, and then obturated using a lateral condensation technique with gutta-percha cones and AH26 Plus as the endodontic sealer. The teeth in the experimental group were instrumented and irrigated without obturation. All teeth in both groups were sealed coronally. After 190 days, the animals were euthanized. Vital perfusion with 10% formalin through common carotid artery was performed. Thirty to 40 serial 5-microm thick sections were obtained from each root and stained with hematoxylin and eosin for histological evaluation by observer blinded to the treatment allocation. The control group showed less cementum and dentin resorption in comparison with test group (p < 0.5). No statistically significant difference was found in other parameters between the control and test groups (p > 0.05). The noteworthy finding of this study was that there was no difference in healing of apical periodontitis between the instrumented and obturated and instrumented and nonobturated root canal system. The success of endodontic treatment ultimately depends on the elimination of the microorganism, host response and mechanical closure (coronal seal) of treated root canals that may provide a potential for future bacterial contamination. 1: Int Endod J. 1991 Nov;24(6):308-16. An SEM study of the effects of different irrigation sequences and ultrasonics. Abbott PV, Heijkoop PS, Cardaci SC, Hume WR , Heithersay GS . University of Western Australia, Perth. The root canals of 30 extracted human teeth with single canals were prepared biomechanically with hand instruments using a flaring technique. Three different irrigation regimes were used, with and without ultrasonic activation of a root canal file. The six irrigation sequences used in this study were as follows: Savlon, Savlon with ultrasound, EDTAC/NaOCl/EDTAC, EDTAC/NaOCl/EDTAC with ultrasound, NaOCl/EDTAC/NaOCl, and NaOCl/EDTAC/NaOCl with ultrasound. Scanning electron microscopic (SEM) examination of the prepared root canal walls showed a complete smear layer when Savlon was used. Ultrasound reduced the amount of smear with Savlon, but did not do so significantly with the other irrigation regimes. The most effective irrigation regime for removing smear layer and other debris was EDTAC/NaOCl/EDTAC. In all groups there was a significant decrease in cleaning efficiency as the apical end of the canal was approached. On 6/15/07, Fred Barnett wrote: And another....from our Brazilian amigos.... Smear layer removal capacity of disinfectant solutions used with and without EDTA for the irrigation of canals 1: Pesqui Odontol Bras. 2003 Oct-Dec;17(4):349-55. Epub 2004 Apr 19. Links Smear layer removal capacity of disinfectant solutions used with and without EDTA for the irrigation of canals: a SEM study. Menezes AC, Zanet CG , Valera MC . School of Dentistry of São José dos Campos, São Paulo State University. The purpose of this study was to carry out a scanning electron microscopic (SEM) analysis of the cleaning qualities and smear layer removal from root canal walls, instrumented and irrigated with 2.5% NaOCl, 2.0% chlorhexidine and saline solutions. Fifty extracted teeth were used in this study. All teeth were radiographed to determine the existence of a single canal. The crowns were cut at the cervical limit and the root canals were instrumented with K-type files up to size 45. During root canal preparation, irrigations were made with the different solutions being evaluated: Group 1: 2.5% NaOCl (10 roots); Group 2: 2.5% NaOCl and 17% EDTA for 2 minute (10 roots); Group 3: 2.0% chlorhexidine (10 roots); Group 4: 2.0% chlorhexidine and 17% EDTA for 2 minutes (10 roots); Group 5: saline solution (5 roots); Group 6: saline solution and 17% EDTA for 2 minutes (5 roots). After instrumentation, the canals were irrigated with each one of the solutions and the roots were cut in the buccolingual direction for SEM analysis, at the cervical, middle and apical thirds, to ascertain the presence or absence of smear layer and debris. SEM analysis was performed by three calibrated examiners and scores were submitted to Kruskal-Wallis test at the significance level of p = 5%. Results showed that the use of 17% EDTA decreased the smear layer significantly (p < 0.05) for all evaluated solutions in all thirds. When EDTA was not used, a significantly higher quantity of smear layer on the apical third was observed only in the NaOCl groups. The use of 17% EDTA was significant for debris removal except for the chlorhexidine groups. The following conclusion could be drawn: the use of 17% EDTA was necessary to enhance cleanness of the root canals. It is not a problem when you rinse one out with the other and let that one work in the canal. Take a look at this paper: A scanning electron microscopic evaluation of different root canal irrigation regimens 1: Braz Oral Res. 2006 Jul-Sep;20(3):235-40. Links A scanning electron microscopic evaluation of different root canal irrigation regimens. Mônika CM, Fröner IC. Department of Restorative Dentistry, School of Dentistry of Ribeirão Preto, University of São Paulo. The purpose of this study was to assess the effectiveness of endodontic irrigants in removing the smear layer from instrumented root canal walls using Scanning Electron Microscopy (SEM). The endodontic irrigants used were: 1% sodium hypochlorite (NaOCl); 1% NaOCl mixed to 17% EDTAC; 2% chlorhexidine gel; and Ricinus communis gel. Photomicrographs of the middle and apical thirds were evaluated with the aid of the Fotoscore - v. 2.0 software. The results indicated that the mixture of sodium hypochlorite and EDTAC completely removed the smear layer from dentinal walls. The other endodontic irrigants were not as efficient in cleansing the root canals. PMID: 17119706 [PubMed - indexed for MEDLINE] Endodontology Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology Volume 104, Issue 1, July 2007, Pages 122-130 Bacteriologic investigation of the effects of sodium hypochlorite and chlorhexidine during the endodontic treatment of teeth with apical periodontitis José F. Siqueira Jr. DDS, PhD a, , , Isabela N. Rôças DDS, PhD a, Simone S.M. Paiva DDS b, Tatiana Guimarães-Pinto DDS b, Karen M. Magalhães DDS b and Kenio C. Lima DDS, PhD c aProfessor, Estácio de Sá University, Rio de Janeiro, RJ, Brazil. bGraduate students, Master's Program in Endodontics, Estácio de Sá University, Rio de Janeiro, RJ, Brazil. cProfessor, Federal University of Rio Grande do Norte, Natal, RN, Brazil. Received 27 December 2006; revised 8 January 2007; accepted 21 January 2007. Available online 11 May 2007. Objective This clinical study was undertaken to compare the effectiveness of 2.5% sodium hypochlorite (NaOCl) and 0.12% chlorhexidine digluconate as irrigants in reducing the cultivable bacterial populations in infected root canals of teeth with apical periodontitis. Study design According to stringent inclusion/exclusion criteria, 32 teeth with primary intraradicular infections and chronic apical periodontitis were selected and followed in the study. Bacterial samples were taken at the baseline (S1) and after chemomechanical preparation using either NaOCl (n = 16) or chlorhexidine (n = 16) as irrigants (S2). Cultivable bacteria recovered from infected root canals at the 2 stages were counted. Isolates from S2 samples were identified by means of 16S rRNA gene sequencing analysis. Results At S1, all canals were positive for bacteria, and the median number of bacteria per canal was 7.32 × 105 for the NaOCl group and 8.5 × 10 5 for the chlorhexidine group. At S2, the median number of bacteria in canals irrigated with NaOCl and chlorhexidine was 2.35 × 103 and 2 × 102, respectively. Six of 16 (37.5%) canals from the NaOCl group and 8 of 16 (50%) canals from the chlorhexidine group yielded negative cultures. Chemomechanical preparation using either solution substantially reduced the number of cultivable bacteria in the canals. No significant difference was observed between the NaOCl and chlorhexidine groups with regard to the number of cases yielding negative cultures (P = .72) or quantitative bacterial reduction (P = .609). The groups irrigated with NaOCl or chlorhexidine showed a mean number of 1.3 and 1.9 cultivable species per canal, respectively. The great majority of isolates in S2 were from gram-positive bacteria, with streptococci as the most prevalent taxa. Conclusions The present findings revealed no significant difference when comparing the antibacterial effects of 2.5% NaOCl and 0.12% chlorhexidine used as irrigants during the treatment of infected canals.
Disinfection describes a process that eliminates many or all-pathogenic microorganisms on inanimate objects with the exception of bacterial spores . NaOCl does NOT disinfect the root canal system. There are boat loads of clinical studies to show this. Both from anaerobic cultivation and using molecular methods. Again....Do you have data to prove your product will disinfect the root canal system? Do you have data to support your claim that Chlor-Xtra will penetrate into microtubules and cracks? - Fred Endod. 2006 Feb;32(2):138-41. Links Killing of Enterococcus faecalis by MTAD and chlorhexidine digluconate with or without cetrimide in the presence or absence of dentine powder or BSA. Portenier I, Waltimo T , Ørstavik D , Haapasalo M . The antibacterial efficacy of irrigating solutions and local disinfectants used in endodontics appears poorer in vivo than in vitro. One explanation may be inactivation by compounds present in the root canal. MTAD (a mixture of tetracycline isomer, acid, and detergent) is a new root canal irrigation solution with antibacterial activity. The aim of this study was to investigate the antibacterial activity of MTAD and chlorhexidine towards two strains of Enterococcus faecalis and the inhibitory effects of dentine and bovine serum albumin on the antibacterial activity. Survival of bacteria exposed to the medicaments in the presence or absence of inhibitors was monitored in an in vitro model. Full concentration (100%) MTAD and 0.2% chlorhexidine rapidly killed both strains. Combining chlorhexidine with cetrimide further reduced the time required for killing. The presence of dentine or BSA caused a marked delay in killing by both medicaments. The two E. faecalis strains tested showed minor differences in their susceptibility to the disinfectants...... so, Cetrimide will enhance microbial kill. DEFINITION OF TERMS Sterilization is the complete elimination or destruction of all forms of microbial life and is accomplished in healthcare facilities by either physical or chemical processes. Steam under pressure, dry heat, ethylene oxide (ETO) gas, hydrogen peroxide gas plasma, and liquid chemicals are the principal sterilizing agents used in healthcare facilities. Sterilization is intended to convey an absolute meaning, not a relative one. Unfortunately, some health professionals as well as the technical and commercial literature refer to "disinfection" as "sterilization" and items as "partially sterile." When chemicals are used for the purposes of destroying all forms of microbiological life, including fungal and bacterial spores, they may be called chemical sterilants. These same germicides used for shorter exposure periods may also be part of the disinfection process ( i.e., high-level disinfection). December 2005, 31:12 > The Impact of Instrument Fracture... The Impact of Instrument Fracture on Outcome of Endodontic Treatment Journal of Endodontics. 31(12):845-850, December 2005. Spili, Peter BSc, BDSc *; Parashos, Peter MDSc, PhD *; Messer, Harold H. MDSc, PhD * Abstract: Adoption of rotary nickel-titanium instruments has renewed concerns regarding instrument fracture and its consequences. The frequency of instrument fracture and its impact on treatment outcome were determined from an analysis of specialist endodontic practice records involving 8460 cases. A case-control study of treatment outcomes was conducted on a subset of 146 teeth with a retained instrument fragment (plus 146 matched controls), for which clinical and radiographic follow-up of at least 1 year was available. Masked radiographs were assessed by two calibrated examiners. Overall prevalence of retained fractured instruments was 3.3% of treated teeth. In the case-control study, overall healing rates were 91.8% for cases with a fractured instrument and 94.5% for matched controls (p > 0.05, Fisher's exact test). Healing in both groups was lower in teeth with a preoperative periapical radiolucency (86.7% versus 92.9%, p > 0.05). In the hands of skilled endodontists prognosis was not significantly affected by the presence of a retained fractured instrument. December 2005, 31:12 > ARTICLE Fracture Resistance of Human Root Dentin Exposed to Intracanal Calcium Hydroxide. Journal of Endodontics. 31(12):895-897, December 2005. Doyon, Glen E. DMD *; Dumsha, Thom MS, DDS, MS *; von Fraunhofer, J Anthony MSc, PhD + Abstract: The purpose of the present study was to determine if exposure to intracanal calcium hydroxide [Ca(OH2)] alters the fracture resistance of human root dentin. One hundred and two freshly extracted single rooted human teeth divided into three groups of 34 teeth each. Coronal access and endodontic instrumentation using round burs, stainless steel files, and Profile GT rotary files were completed for each tooth. The prepared root canal system of each tooth was filled with saline solution (group 1), USP Ca(OH)2 (group 2), or Metapaste (group 3). The apicies and access openings were sealed with composite resin and the teeth were immersed in saline. After 30 days, the roots of 17 teeth from each group were sectioned horizontally into 1-mm thick disks and each disk was loaded to fracture at 2.5 mm/min with a SATEC universal- testing machine. After 180 days the same procedure was performed on the remaining 17 teeth in each of the 3 groups. The peak load at fracture was measured for each dentin disk. Data were analyzed using one-way ANOVA and a post hoc Student- Newman-Keuls test. After 30 days exposure to the test solution, there was no difference in the peak load at fracture for the three groups of teeth. However, after 180 days, the roots of the teeth exposed to USP Ca(OH)2 showed a significant decrease in peak load at fracture when compared to the 30-day groups and the 180-day groups exposed to saline or Metapaste. December 2005, 31:12 > Does Hybridization of Intraradicular... ARTICLE Does Hybridization of Intraradicular Dentin Really Improve Fiber Post Retention in Endodontically Treated Teeth? Journal of Endodontics. 31(12):891-894, December 2005. Pirani, Chiara *; Chersoni, Stefano *; Foschi, Federico *+; Piana, Gabriela *; Loushine, Robert J. ++; Tay, Franklin R. [S]; Prati, Carlo * Abstract: This study tested the hypothesis that hybridization of intraradicular dentin eliminates interfacial gaps, thereby improving the coronal seal and retention of teeth restored with fiber posts. Post spaces were bonded with two types of fiber posts, using the corresponding etch-and-rinse adhesives and dual-cured resin cements. Longitudinal sections of the interfaces were examined for dentin hybridization in the coronal- and middle-thirds of the root canals. Resin replicas of these sections were evaluated for interfacial gap formation. Although intraradicular dentin hybridization was not compromised irrespective of whether the adhesives were light-cured before cementation, the universal occurrence of interfacial gaps along the hybrid layer surface or the post-cement interface reflects the challenge in bonding to post spaces with low compliance and high C-factors. The clinical success associated with bonded fiber posts is probably due predominantly to frictional retention. Clinical Oral Implants Research Online Early doi:10.1111/j.1600-0501.2005.01190.x Volume 0 Issue 0 Comparisons of bacterial patterns present at implant and tooth sites in subjects on supportive periodontal therapy I. Impact of clinical variables, gender and smoking Mette R. Agerbaek1, Niklaus P. Lang1 and G. Rutger Persson1,2 Abstract Objective: (I) To compare the oral microflora at implant and tooth sites in subjects participating in a periodontal recall program, (II) to test whether the microflora at implant and tooth sites differ as an effect of gingival bleeding (bleeding on probing (BOP)), or pocket probing depth (PPD), and (III) to test whether smoking and gender had an impact on the microflora. Material and methods: Data were collected from 127 implants and all teeth in 56 subjects. Microbiological data were identified by the DNA–DNA checkerboard hybridization. Results: PPD=4 mm were found in 16.9% of tooth, and at 26.6% of implant sites (P<0.01). Tooth sites with PPD=4 mm had a 3.1-fold higher bacterial load than implant sites (mean difference: 66%, 95% confidence interval (CI): 40.7–91.3, P< 0.001). No differences were found for the red, orange, green, and yellow complexes. A higher total bacterial load was found at implant sites with PPD=4 mm (mean difference 35.7 × 105, 95% CI: 5.2 (105) to 66.1 (105), P<0.02 with equal variance not assumed). At implant sites, BOP had no impact on bacterial load but influenced the load at tooth sites (P< 0.01). Conclusion: BOP, and smoking had no impact on bacteria at implant sites but influenced the bacterial load at tooth sites. Tooth sites harbored more bacteria than implant sites with comparable PPD. The 4 mm PPD cutoff level influenced the distribution and amounts of bacterial loads. The subject factor is explanatory to bacterial load at both tooth and implant sites. To cite this article: Agerbaek MR, Lang NP, Persson GR. Comparisons of bacterial patterns present at implant and tooth sites in subjects on supportive periodontal therapy. I. Impact of clinical variables, gender and smoking. Clinical Oral Implants Research Online Early doi:10.1111/j.1600-0501.2005.01196.x Volume 0 Issue 0 Dental implants placed in expanded narrow edentulous ridges with the Extension Crest® device A 1–3-year multicenter follow-up study Matteo Chiapasco1, Francesco Ferrini2, Paolo Casentini3, Stefano Accardi1 and Marco Zaniboni1 Abstract Objective: This study has been designed to evaluate the capability of a new surgical device (Extension Crest®) to widen narrow edentulous alveolar ridges and to allow a correct placement of endosseous implants in horizontally atrophied sites. Material and methods: Forty-five patients, 20 males and 25 females, aged 20–66 years, affected by edentulism associated to horizontal resorption of the ridges, were treated by means of a sagittal osteotomy and expansion of the ridge with a new surgical device (Extension Crest®) to obtain a wider bony base for ideal implant placement. In the same procedure in 33 patients, and 1 week afterwards in 12 patients, 110 endosseous titanium implants (ITI TE®) were placed. Three to four months later, the patients were rehabilitated with implant-supported prostheses. Results: The success rate of the expansion technique was 97.8%. A total of 110 implants were inserted in the expanded ridges. The mean follow-up after the start of prosthetic loading was 20.4 months. Three implants were removed before the start of prosthetic loading, because of non-integration, while no other implants failed after the completion of the prosthetic rehabilitation. Three implants, although integrated and in function, did not fulfill success criteria: cumulative success and survival rates at the end of the observation period were 95.4% and 97.3%, respectively. Conclusion: Within the limits of this study, this technique appeared to be reliable and simple, with reduction of morbidity and times of dental rehabilitation as compared with other techniques such as autogenous bone grafts and guided bone regeneration. Survival and success rates of implants placed in the treated areas are consistent with those placed in native bone. To cite this article: Chiapasco M, Ferrini F, Casentini P, Accardi S, Zaniboni M. Dental implants placed in expanded narrow edentulous ridges Clinical Oral Implants Research Online Early doi:10.1111/j.1600-0501.2005.01197.x Volume 0 Issue 0 Comparison of bacterial plaque samples from titanium implant and tooth surfaces by different methods Jeanne Gerber1, Doris Wenaweser1, Lisa Heitz-Mayfield1, Niklaus P. Lang1 and G. Rutger Persson1,2 Abstract: Studies have shown similarities in the microflora between titanium implants or tooth sites when samples are taken by gingival crevicular fluid (GCF) sampling methods. The purpose of the present study was to study the microflora from curette and GCF samples using the checkerboard DNA–DNA hybridization method to assess the microflora of patients who had at least one oral osseo-integrated implant and who were otherwise dentate. Plaque samples were taken from tooth/implant surfaces and from sulcular gingival surfaces with curettes, and from gingival fluid using filter papers. A total of 28 subjects (11 females) were enrolled in the study. The mean age of the subjects was 64.1 years (SD±4.7). On average, the implants studied had been in function for 3.7 years (SD±2.9). The proportion of Streptococcus oralis (P <0.02) and Fusobacterium periodonticum (P<0.02) was significantly higher at tooth sites (curette samples). The GCF samples yielded higher proportions for 28/40 species studies (P-values varying between 0.05 and 0.001). The proportions of Tannerella forsythia (T. forsythensis), and Treponema denticola were both higher in GCF samples (P<0.02 and P<0.05, respectively) than in curette samples (implant sites). The microbial composition in gingival fluid from samples taken at implant sites differed partly from that of curette samples taken from implant surfaces or from sulcular soft tissues, providing higher counts for most bacteria studied at implant surfaces, but with the exception of Porphyromonas gingivalis. A combination of GCF and curette sampling methods might be the most representative sample method. To cite this article: Gerber J, Wenaweser D, Heitz-Mayfield L, Lang NP, Persson RG. Comparison of bacterial plaque samples from titanium implant and tooth surfaces by different methods.