Endodontic Treatment of a Large Cyst-Like Periradicular Lesion Using a Combination of Antibiotic Drugs: A Case Report
Ülkü Özan, DDS, and Kürşat Er, DDS, PhD*
Fracture Resistance of Human Root Dentin Exposed to Intracanal Calcium Hydroxide
Glen E. Doyon, DMD, Thom Dumsha, MS, DDS, MS, and J. Anthony von Fraunhofer, MSc, PhD
Atomic Force Microscopy Study of Stainless-Steel and Nickel-Titanium Files
Caroline R. A. Valois, MSc, Luciano P. Silva, PhD and Ricardo B. Azevedo, PhD
Does Hybridization of Intraradicular Dentin Really Improve Fiber Post Retention in Endodontically Treated Teeth?
Chiara Pirani, Stefano Chersoni, Federico Foschi, Gabriela Piana, Robert J. Loushine, Franklin R. Tay, and Carlo Prati
Apical Leakage of Resin Based Root Canal Sealers with a New Computerized Fluid Filtration Meter
Hasan Orucoglu, DDS, PhD, Abdulkadir Sengun, DDS, PhD, and Nihat Yilmaz, DDS, PhD
An In Vitro Model to Investigate Filling of Lateral Canals
Mauro Venturi, MD, DDS, Roberto Di Lenarda, DDS, Carlo Prati, MD, DDS, PhD, and Lorenzo Breschi, DDS, PhD
A Comparison of the Machining Efficiency of Two Brands of Stainless Steel Endodontic Hand Files
Gregory J. Dearing, DMD, Reza B. Kazemi, DMD, and Roy H. Stevens, DDS, MS
The Role of Environmental Changes on Monospecies Biofilm Formation on Root Canal Wall by Enterococcus faecalis
S. George, BSc, MSc, A. Kishen, BDS, MDS, PhD, and K. P. Song, BDS, PhD
Infection Control and One Year Follow-Up of Periapical Healing
Tuomas Waltimo, DDS, PhD, Martin Trope, DMD, BDS, Markus Haapasalo, DDS, PhD, and Dag Ørstavik, DDS, PhD
The Upregulation of Matrix Metalloproteinase-9 in Inflamed Human Dental Pulps
Chung-Hung Tsai, DDS, MPH, Yi-Juai Chen, DDS, MSD, Fu-Mei Huang, DDS, MS, Ying-Fang Su, DDS, MSD, and Yu-Chao Chang, DDS, MS, PhD
The Effect of Cavity Preparation on Substance P Expression in Human Dental Pulp
Javier Caviedes-Bucheli, MSc, José Antonio Correa-Ortíz, DDS, Leydy Viviana García, DDS, Rocío López-Torres, DDS, Nelson Lombana, MSc, and Hugo Roberto Muñoz, MSc
Enterococcus Spp. in Endodontically Treated Teeth with and without Periradicular Lesions
Blythe Kaufman, DMD, Larz Spångberg, DDS, PhD, Jody Barry, BA, MT (ASCP), and Ashraf F. Fouad, DDS, MS
The Impact of Instrument Fracture on Outcome of Endodontic Treatment
Peter Spili, BSc, BDSc, Peter Parashos, MDSc, PhD, and Harold H. Messer, MDSc, PhD
Endodontic Treatment of a Large Cyst-Like Periradicular Lesion Using a Combination of Antibiotic Drugs: A Case Report
Ülkü Özan, DDS, and Kürşat Er, DDS, PhD*
This case report describes the endodontic treatment of a large cyst-like periradicular lesion using a combination of antibiotic drugs. A 15-yr-old boy with a large cyst-like lesion from the apices of his teeth 29 to 31. Conservative root canal treatment was performed (tooth #30). During treatment procedure, 2.5% sodium hypochlorite solution was used for irrigation and a combination of antibiotic drugs was used for the intracanal dressing. Periapical healing was observed 3-month after initial treatment and continued at the 7-month review.
Fracture Resistance of Human Root Dentin Exposed to Intracanal Calcium Hydroxide
Glen E. Doyon, DMD, Thom Dumsha, MS, DDS, MS, and J. Anthony von Fraunhofer, MSc, PhD
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.
Atomic Force Microscopy Study of Stainless-Steel and Nickel-Titanium Files
Caroline R. A. Valois, MSc, Luciano P. Silva, PhD and Ricardo B. Azevedo, PhD
Atomic force microscopy (AFM) is a well established and documented tool for materials investigation. The aim of this study was to evaluate the topography of conventional stainless-steel files and both hand and rotary nickel-titanium (NiTi) files by using AFM. One endodontic file of each of the following was selected: stainless-steel K-file Dentsply, stainless-steel K-file Moyco, hand NiTi K-file Nitiflex, hand NiTi Greater Taper, rotary NiTi Greater Taper, and rotary NiTi Quantec. The analyses were performed on twenty different points located along a 3-mm section starting at the tip of each file. Root mean square (RMS) parameters for contact mode imaging microscopy variations were measured. The differences between RMS values were tested by ANOVA with Fisher’s protected LSD test for multiple comparisons (p < 0.05). RMS of depth profile data was used to determine any statistically significant difference in vertical amplitude. According to results, all instruments showed topographic irregularities distributed on surface. Endodontic files manufactured by the same method and alloy demonstrated significant differences, whereas no significant differences were found for instruments produced by different alloys and methods (p < 0.05). The hand NiTi Greater Taper, rotary NiTi Greater Taper, and rotary NiTi Quantec showed greater values of vertical amplitude topography compared to K-Dentsply and Nitiflex files (p < 0.05). The AFM technique proved to be a valuable research tool in the investigation of endodontic files topography.
Does Hybridization of Intraradicular Dentin Really Improve Fiber Post Retention in Endodontically Treated Teeth?
Chiara Pirani, Stefano Chersoni, Federico Foschi, Gabriela Piana, Robert J. Loushine, Franklin R. Tay, and Carlo Prati
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.
Apical Leakage of Resin Based Root Canal Sealers with a New Computerized Fluid Filtration Meter
Hasan Orucoglu, DDS, PhD, Abdulkadir Sengun, DDS, PhD, and Nihat Yilmaz, DDS, PhD
In this in vitro study, the apical leakage of three root canal sealers: AH Plus, Diaket, and EndoREZ was evaluated using a new computerized fluid filtration meter. Forty-five extracted human premolar teeth with single root and canal were used. The coronal part of each tooth was removed and the root canals were prepared using GT Rotary files and crown-down technique. The roots were randomly divided into three groups of 15 samples, filled with one of the test materials and gutta-percha cones by the cold lateral condensation technique and were stored at 37°C and 100% humidity for 7 days. One-week later, apical parts of roots of 10 ± 0.05 mm were attached to computerized fluid filtration meter. Apical leakage quantity was determined as μl/ cmH₂O/min¯¹. Statistical analysis indicated that root fillings with Diaket in combination with cold lateral condensation technique showed lower apical leakage than the others (p < 0.05). In addition, this new computerized fluid filtration meter allowed quantitative measurement of leakage easily. As it is a newly developed device to measure apical leakage of endodontic sealers, the reliability of it needed to be tested.
An In Vitro Model to Investigate Filling of Lateral Canals
Mauro Venturi, MD, DDS, Roberto Di Lenarda, DDS, Carlo Prati, MD, DDS, PhD, and Lorenzo Breschi, DDS, PhD
Aims of this work were to examine lateral canals in extracted teeth, to propose a new technique to produce artificial lateral canals, and to compare two obturation techniques. Cleared roots were examined to record measure and shape of lateral canals. Artificial lateral canals were prepared on human demineralized teeth before final clearing. Specimens were divided in two groups: canals of group 1 were filled with Schilder’s technique, canals of group 2 were filled with vertical compaction with apical backfilling. Stereomicroscopic analysis of lateral canal filling revealed lower filling rates in apical canals compared to coronal ones and higher filling rates with “vertical compaction with apical backfilling” compared to Schilder’s group. The tested procedure appears to be a reliable technique to obtain standardized lateral canals and to compare filling procedures.
A Comparison of the Machining Efficiency of Two Brands of Stainless Steel Endodontic Hand Files
Gregory J. Dearing, DMD, Reza B. Kazemi, DMD, and Roy H. Stevens, DDS, MS
The purpose of this study was to compare the machining efficiency of a flexible stainless steel K-type hand file recently introduced by Brasseler USA (“F-Style files”), with that of a well-studied Endodontic instrument (“Flex-o-files,” Maillefer Dentsply), that has been on the market for more than 20 years. The comparison of machining efficiencies of these two brands of files was conducted on both dentin and plexiglas substrates, using an apparatus that allowed a constant force to be applied from each file being tested. The results indicated that the Brasseler instruments had poorer machining efficiency than those of the Maillefer files.
The Role of Environmental Changes on Monospecies Biofilm Formation on Root Canal Wall by Enterococcus faecalis
S. George, BSc, MSc, A. Kishen, BDS, MDS, PhD, and K. P. Song, BDS, PhD
Biofilm mode of growth is a strategy in microorganisms to survive harsh growth conditions. Although previous studies have established the ability of Enterococcus faecalis to survive postendodontic environmental conditions, the effect of such conditions on the ultrastructural and physiochemical features of E. faecalis biofilm has received less attention. This study aims to evaluate the effect of different growth conditions on the characteristics of E. faecalis biofilm on root canal, and the penetration of E. faecalis into dentinal tubules. Fortyfive intact noncarious human maxillary molars were experimented under nutrient-rich, nutrient-deprived, aerobic, and anaerobic conditions for a period of 21 days. Scanning Electron Microscopy with Energy Dispersive X-ray microanalysis, Laser Confocal Scanning Microscopy and Light microscopic examinations were carried out. The microscopic analysis highlighted a distinct variation in the ultrastructure of the biofilms formed under different experimental conditions. The EDX microanalysis showed a significant increase in the levels of Calcium (Ca) in the biofilm structures formed under anaerobic nutrient-deprived condition (p < 0.001). The depth of bacterial penetration was significantly greater in nutrient-rich condition (p < 0.001). This study demonstrated distinct ultrastructural and physiochemical properties of the biofilms formed and dentinal tubular penetration of E. faecalis under different conditions.
Infection Control and One Year Follow-Up of Periapical Healing
Tuomas Waltimo, DDS, PhD, Martin Trope, DMD, BDS, Markus Haapasalo, DDS, PhD, and Dag Ørstavik, DDS, PhD
The objective was to evaluate the clinical efficacy of chemomechanical preparation of the root canals with sodium hypochlorite and interappointment medication with calcium hydroxide in the control of root canal infection and healing of periapical lesions. Fifty teeth diagnosed with chronic apical periodontitis were randomly allocated to one of three treatments: Single visit (SV group, n = 20), calcium hydroxide for one week (CH group n= 18), or leaving the canal empty but sealed for one week (EC group, n = 12). Microbiological samples were taken to monitor the infection during treatment. Periapical healing was controlled radiographically following the change in the periapical index at 52 wk and analyzed using one-way ANOVA. All cases showed microbiological growth in the beginning of the treatment. After mechanical preparation and irrigation with sodium hypochlorite in the first appointment, 20 to 33% of the cases showed growth. At the second appointment 33% of the cases in the CH group revealed bacteria, whereas the EC group showed remarkably more culture positive cases 67%). Sodium hypochlorite was effective also at the second appointment and only two teeth remained culture positive. Only minor differences in periapical healing were observed between the treatment groups. However, bacterial growth at the second appointment had a significant negative impact on healing of the periapical lesion (p < 0.01). The present study indicates good clinical efficacy of sodium hypochlorite irrigation in the control of root canal infection. Calcium hydroxide dressing between the appointments did not show the expected effect in disinfection the root canal system and treatment outcome, indicating the need to develop more efficient interappointment dressings.
The Upregulation of Matrix Metalloproteinase-9 in Inflamed Human Dental Pulps
Chung-Hung Tsai, DDS, MPH, Yi-Juai Chen, DDS, MSD, Fu-Mei Huang, DDS, MS, Ying-Fang Su, DDS, MSD, and Yu-Chao Chang, DDS, MS, PhD
The matrix metalloproteinases (MMPs) participate in a wide variety of extracellular matrix degradation. Detailed knowledge of MMPs may be important for understanding the pathogenesis of pulpal inflammation. The purpose of this study was to compare MMP-9 expression in clinically healthy human pulp and inflamed human pulp tissue specimens. We compared the levels of MMP-9 between clinically healthy pulp and inflamed pulp tissues by using the semi-quantitative reverse-transcriptase polymerase chain reaction analysis. In addition, immunohistochemistry was used to identify the in situ localization of MMP-9 expression in pulp specimens. MMP-9 mRNA gene was found to be increased in inflamed pulps as compared with clinically healthy pulp tissues (p < 0.05). The results from immunohistochemistry demonstrated that MMP-9 expression was significantly higher in the inflamed pulps than clinically healthy pulps (p < 0.05). MMP-9 stain was detected in the odontoblasts, fibroblasts, inflammatory infiltrates, and endothelial cells. Taken together, MMP-9 may play an important role in the pathogenesis of pulpal inflammation.
The Effect of Cavity Preparation on Substance P Expression in Human Dental Pulp
Javier Caviedes-Bucheli, MSc, José Antonio Correa-Ortíz, DDS, Leydy Viviana García, DDS, Rocío López-Torres, DDS, Nelson Lombana, MSc, and Hugo Roberto Muñoz, MSc
Substance P (SP) plays an important role during neurogenic inflammation of dental pulp. The purpose of this study was to use a radioimmunoassay for determining the effect of cavity preparation on SP expression in healthy human dental pulp. Ten pulp samples were obtained from healthy premolars where extraction was indicated for orthodontic reasons. Deep cavity preparation (<1 mm remaining dentine thickness) was performed before extraction in five of these bicuspids. All samples were processed and ¹²⁵I-SP labeled; SP was quantified by competition assay. The results revealed SP expression in all human pulp samples. Mann-Whitney’s U test revealed statistically significant higher expression in pulp from teeth where cavity preparation had been performed compared to control values (p < 0.05). These findings suggest that SP is released during common dental procedures (such as cavity preparation) and its expression may have an important clinical significance in terms of experiencing inflammation and pain.
Enterococcus Spp. in Endodontically Treated Teeth with and without Periradicular Lesions
Blythe Kaufman, DMD, Larz Spångberg, DDS, PhD, Jody Barry, BA, MT (ASCP), and Ashraf F. Fouad, DDS, MS
The purpose of this study was to determine if Enterococcus spp. are more prevalent in endodontically treated teeth with periradicular lesions compared with teeth that require retreatment but have no periradicular rarefaction. Fifty-eight teeth that had received root canal therapy more than 1 yr previously and required retreatment were included. Designation of lesion versus no lesion was determined by two experienced endodontists. DNA extraction and PCR amplification were performed using ubiquitous 16S rDNA bacterial primers, as well as Enterococcus spp.-specific primers. The results showed that the overall prevalence of bacteria was 90% and Enterococcus spp. was 12%. χ² analysis revealed a statistically significant relationship between the presence of a lesion and the presence of bacteria, as detected by the universal primers (p = 0.032). Using logistic regression, a statistically significant relationship was found between teeth with normal periapex and the presence of Enterococcus spp. (p = 0.023). This study revealed that bacteria are significantly associated with endodontic treatment failure but enterococci are not associated with disease.
The Impact of Instrument Fracture on Outcome of Endodontic Treatment
Peter Spili, BSc, BDSc, Peter Parashos, MDSc, PhD, and Harold H. Messer, MDSc, PhD
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.