Morphologic Study of Nd:YAG Laser Usage in Treatment of Dentinal Hypersensitivity
Wan-Hong Lan, Bor-Shiunn Lee, Hsin-Cheng Liu, and Chun-Pin Lin
Nested PCR Detection of Centipeda periodontii in Primary Endodontic Infections
José F. Siqueira Jr, and Isabela N. Rôças
Effect of Gingiva on Laser Doppler Pulpal Blood Flow Measurements
Kerem Engin Akpinar, Kürsat Er, Serkan Polat, and Nilüfer Tülin Polat
Geographical Differences in Bacteria Detected in Endodontic Infections Using Polymerase Chain Reaction
J. C. Baumgartner, J. F. Siqueira, Jr., T. Xia, and I. N. Rôças,
Prognosis of Intentional Replantation of Vertically Fractured Roots Reconstructed with Dentin-Bonded Resin
Mikako Hayashi, Yoshifumi Kinomoto, Fumio Takeshige, and Shigeyuki Ebisu
Vasoactive Response of Isolated Pulpal Arterioles to Endothelin-1
Christine Y. Yu, Nick M. Boyd, Stephen J. Cringle, Er-Ning Su, and Dao-Yi Yu
In Vitro Microbial Leakage of Endodontically Treated Teeth Using New and Standard Obturation Techniques
Guy Shipper and Martin Trope
The Properties of Endocal 10 and Its Potential Impact on the Structural Integrity of the Root
Robert A. Goldberg, Sergio Kuttler, and Samuel O. Dorn
In Vitro Comparison of Shaping Abilities of ProTaper and GT Rotary Files
Mario Veltri, Aniello Mollo, Pier Paolo Pini, Luca Fernando Ghelli, and Piero Balleri
Evaluation of Ultrasonically Placed MTA and Fracture Resistance with Intracanal Composite Resin in a Model of Apexification
G. Robert Lawley, William G. Schindler, William A. Walker III, and David Kolodrubetz
Influence of Ultrasound, With and Without Water Spray Cooling, on Removal of Posts Cemented With Resin or Zinc Phosphate Cements
Ângela Delfina Bittencourt Garrido, Tabajara Sabbag Fonseca, Edson Alfredo, Yara Teresinha Corrêa Silva-Sousa,and Manoel D. Sousa-Neto
Effect of a Separated Instrument on Bacterial Penetration of Obturated Root Canals
Jeffrey L. Saunders, Paul D. Eleazer, Ping Zhang, and Susanne Michalek
Accidental Sodium Hypochlorite-Induced Skin Injury During Endodontic Treatment
Ahmet Serper, Murat Özbek, and Semra Çalt
Glandular Odontogenic Cyst
Phuong-Thao Tran, Charles J. Cunningham, and Ronald A. Baughman
Middle Mesial Canal of the Mandibular First Molar: A Case Report and Literature Review
Dean Baugh and James Wallace
Morphologic Study of Nd:YAG Laser Usage in Treatment of Dentinal Hypersensitivity
Wan-Hong Lan, DDS, PhD, Bor-Shiunn Lee, DDS, MS, PhD, Hsin-Cheng Liu, DDS, MS, PhD, and Chun-Pin Lin, DDS, MS, PhD
Our previous in vitro study indicated that Nd:YAG laser irradiation on dentin could melt normal dentin surface and close the exposed dentinal tubule orifices without creating surface cracks. This study evaluated the morphologic changes of hypersensitive dentin after Nd:YAG laser irradiation. Thirty patients with clinically diagnosed cervical dentin hypersensitive teeth were treated with a Nd:YAG laser of 30 mJ intensity at 10 pulses per second for 2 min. An impression of the sensitive area was taken before and after laser treatment and then examined with a scanning electron microscope. The impression of the dentin surface after Nd:YAG laser treatment showed no protrusive rods, in contrast with the presence of numerous rods before laser irradiation. Because protrusive rods are a measure of open dentinal tubules, we interpret these data to support the hypothesis that Nd:YAG laser irradiation at specifications of 30 mJ, 10 pulses per second, and 2 min can be used to seal the exposed dentinal tubules.
Nested PCR Detection of Centipeda periodontii in Primary Endodontic Infections
José F. Siqueira Jr, DDS, MSc, PhD, and Isabela N. Rôças, DDS, MSc
In recent years, molecular genetic methodologies have provided significant additional knowledge about components of the microbiota associated with infections of endodontic origin. Following this research line, the purpose of the present study was to investigate the prevalence of Centipeda periodontii in primary endodontic infections using a species-specific nested PCR assay. Samples were collected from fifty teeth having carious lesions, necrotic pulps, and different forms of periradicular diseases. DNA extracted from the samples was initially amplified using universal 16S rDNA primers, and a second round of amplification used the first PCR products to detect a specific fragment of C. periodontii 16S rDNA. This species was detected in 3 (13%) of 23 asymptomatic cases, in 1 (14%) of 7 cases diagnosed as acute apical periodontitis, and in 3 (15%) of 20 pus samples aspirated from acute periradicular abscesses. There was no significant association between C. periodontii and the presence of clinical symptoms. Overall, C. periodontii was detected in 14% of the cases of endodontic infections. This is probably the hitherto first study to detect C. periodontii in primary endodontic infections. The specific role played by this bacterial species in infections of endodontic origin awaits further clarification.
Effect of Gingiva on Laser Doppler Pulpal BloodFlow Measurements
Kerem Engin Akpinar, DDS, PhD, Kürsat Er, DDS, Serkan Polat, DDS, PhD, and Nilüfer Tülin Polat, DDS, PhD
The purpose of this study was to evaluate the effect of labial and palatinal gingiva on laser Doppler pulpal blood flow measurements. Twenty upper central incisor teeth determined to be vital from 20 volunteers were included into the study. To stabilize the probe, a laboratory-made acrylic splint positioned the probe labially on the cervical third of the tooth crown. We collected measurements without any gingival covering, and under three conditions: after application of an opaque paste on the labial gingiva, the palatal gingiva, or both the labial and palatal gingiva. The measurement values decreased 46% when there was opaque paste on labial gingiva, 10% on palatinal gingiva, and 63% on both. The decrease in the values when there was an opaque paste on palatinal gingiva was not statistically significant (p > 0.05). The differences between all other groups were statistically significant (p < 0.05). In these measurements, the contribution of labial gingiva to laser Doppler pulpal blood flow measurements is more than that of palatinal gingiva.
Geographical Differences in Bacteria Detected in Endodontic Infections Using Polymerase Chain Reaction
J. C. Baumgartner, DDS, PhD, J. F. Siqueira, Jr., DDS, PhD, T. Xia, DDS, and I. N. Rôças, DDS
The polymerase chain reaction (PCR) is an innovative nucleic acid-based assay that has the highest sensitivity of any microbiological technique for the detection of bacteria. The purpose of this study was to use PCR to detect the presence of specific species of bacteria in samples collected from two geographical locations. Microbial samples from abscesses of endodontic origin were collected from patients in Portland, Oregon, and Rio de Janeiro, Brazil. PCRs with species specific oligonucleotide primers for the 16S ribosomal RNA gene were used for detection of the bacteria after DNA extraction from each clinical sample. Statistical analysis revealed that there was a significant difference in detection of the bacteria between the two geographical locations for Prevotella intermedia, Prevotella nigrescens, Prevotella tannerae, Fusobacterium nucleatum, and Porphyromonas gingivalis, but not for Porphyromonas endodontalis, Fusobacterium necrophorum, and Enterococcus faecalis. These results suggest that differences in bacteria detected or cultured in studies can be associated with geographical location.
Prognosis of Intentional Replantation of Vertically Fractured Roots Reconstructed with Dentin-Bonded Resin
Mikako Hayashi, DDS, PhD, Yoshifumi Kinomoto, DDS, PhD, Fumio Takeshige, DDS, PhD, and Shigeyuki Ebisu, DDS, PhD
There is no particular treatment established to preserve vertically fractured teeth. We evaluated the long-term prognosis of the intentional replantation of26 vertically fractured roots after reconstruction with 4-META/MMA-TBB dentin-bonded resin. Replanted teeth were evaluated according to clinical criteria and radiographic examinations for periods ranging from 4 to 76 months. Eighteen cases were functional and retained, with six fully successful; the others needed further observation. Eight cases failed to respond to treatment because of refracture, recurrence of gingival inflammation, or both. Longevity was calculated as 88.5% at 12 months after replantation, 69.2% at 36 months, and 59.3% at 60 months. All failures occurred in premolar and molar teeth. Longitudinal fractures extending more than 2/3 from the cervical portion toward the apex showed significantly shorter longevity compared with fractures within the 2/3 area (log-rank test, p = 0.02). Intentional replantation of vertically fractured roots reconstructed with dentin bonded resin may be considered for incisors as an alternative to extraction, although the long term success is not optimal.
Vasoactive Response of Isolated Pulpal Arterioles to Endothelin-1
Christine Y. Yu, BDSc, PhD, Nick M. Boyd, BDS, PhD, Stephen J. Cringle, PhD, Er-Ning Su, MD, PhD, and Dao-Yi Yu, MD, PhD
The vasoactive effect of endothelin-1 applied intraluminally or extraluminally was studied in vitro in isolated perfused porcine pulpal arterioles using a microperfusion system. Pulpal arterioles (outer diameter, 94.2 ± 2.8 µm, n = 12) were cannulated and perfused at a constant flow rate in an environment-controlled bath on the stage of an inverted microscope. The vessel diameters were measured online. Both intraluminal and extraluminal application of endothelin-1 (10-16 M to 10-8 M) induced dose-dependent constrictions, reaching 82.3 ± 1.7% (n _=12) and 70.5 ± 1.3% (n = 12) at 10-8 M, respectively. Nifedipine reversed endothelin-1–induced constriction dose dependently at 10-7 M and above. These data demonstrate that endothelin-1 induces calcium dependent vasoconstriction in porcine pulpal arterioles, with extraluminal application more potent, which seems to reflect the possible modulation of vascular endothelium in the control of vascular tone.
In Vitro Microbial Leakage of Endodontically Treated Teeth Using New and Standard Obturation Techniques
Guy Shipper, BDS, MDent, and Martin Trope, BDS, DMD
Coronal microbial leakage is an important cause of apical periodontitis and thus should be prevented if possible. The purpose of this study was to compare microbial leakage of new and standard obturation techniques over a 30-day period. A split chamber microbial leakage model was used in which Streptococcus mutans placed in the upper chamber could reach the lower chamber only through the obturated canal. Leakage was assessed every day for 30 days. One hundred forty single-rooted human teeth were used in this study, equally split between lateral, vertical, and Obtura II condensation; SimpliFill with Obtura II condensation; FibreFill; and a combination of FibreFill and SimpliFill. Cochran-Mantel-Haenszel row mean score statistics showed a high statistical significance when all groups were compared (p<0.0001). Microbial leakage occurred more quickly in lateral and vertical condensation techniques compared with SimpliFill and FibreFill techniques. A combination of an apical plug of gutta-percha with SimpliFill and a FibreFill coronal seal was the best obturation technique used (SimpliFill-FibreFill group).
The Properties of Endocal 10 and Its Potential Impact on the Structural Integrity of the Root
Robert A. Goldberg, DDS, Sergio Kuttler, DDS, and Samuel O. Dorn, DDS
The purpose of this research was to determine if the use of Endocal 10 (previously called Biocalex 6.9) is associated with root fracture and to assess its sealability. Thirty-six freshly extracted, single canal human mandibular incisors were instrumented and randomly divided into two equal groups (n _ 15). Canals in group A were obturated with vertically compacted gutta-percha and Sealapex, and those in group B were filled with Endocal 10 placed with a #25 Lentulo spiral per manufacturer’s instructions. Two blinded investigators evaluated the teeth for fractures using transillumination and an operating microscope at 12_ magnification. Three of the fifteen samples filled with Endocal 10 had vertically fractured in half, whereas none of the teeth filled with gutta-percha had any evident fracture lines. The remaining teeth were tested for leakage via a fluid filtration model at 1 wk and 30 days postobturation. No leakage was found among any of the samples whether filled with gutta- percha or with Endocal 10 at either time interval. Statistical analyses were completed using Fisher’s exact test (p _ 0.023), which showed that there was a significant increase in chance of fracture when using Endocal 10 versus gutta-percha. The results indicate that, although Endocal 10 is able to seal the tooth as well as gutta-percha and sealer, there is a significant potential risk of root fracture.
In Vitro Comparison of Shaping Abilities ofProTaper and GT Rotary Files
Mario Veltri, DDS, Aniello Mollo, DDS, Pier Paolo Pini, DDS, Luca Fernando Ghelli, DDS, and Piero Balleri, MD, DDS
This study analyzed the abilities of ProTaper and GT Rotary files to shape the curved canals of extracted mandibular molars. Twenty mesial canals with curvatures ranging from 23 to 54 degrees (Weine analysis) were radiographically selected from a group of 58 molars. The specimens, divided into two groups, were instrumented using the two systems according to the manufacturer’s guidelines. Using a radiographic platform and a contrast medium, reproducible preinstrumentation and postinstrumentation radiographs were taken. A computer analysis allowed magnification and superimposition of the images to measure the preparation asymmetry and the linear amount of dentin removal at five points along the canals and to detect canal aberrations. Instrument failures, working time, and working length changes were recorded. The dentin removal and the mean asymmetry showed no significant differences between the two systems. Neither aberrations nor significant changes in working length resulted, but two instruments separated in each group. Working time was shorter for ProTaper files (p < 0.05).
Evaluation of Ultrasonically Placed MTA and Fracture Resistance with Intracanal Composite Resin in a Model of Apexification
G. Robert Lawley, DDS, William G. Schindler, DDS, MS, William A. Walker III, DDS, MS and David Kolodrubetz, PhD
The purpose of this study was to evaluate whether intracoronal delivery of an apical barrier of mineral trioxide aggregate (MTA) placed ultrasonically, non-ultrasonically, or ultrasonically with the addition of an intracanal composite resin provided a better seal against bacterial leakage. A second purpose was to determine whether intracanal composite resin or gutta-percha and sealer placed against an apical barrier of MTA provided greater resistance to root fracture. In a standardized in vitro open apex model, MTA was placed as an apical barrier at a thickness of 4 mm, with and without ultrasonic vibration. The barriers were challenged with bacteria exposure within a leakage model, and fracture resistance was assessed with increasing forces applied via an Instron machine. After 45 days, the addition of ultrasonics significantly improved the MTA seal, compared with the non-ultrasonics treatment (Kruskal Wallis nonparametric ANOVA with Dunn multiple comparison test p < 0.05). Bacterial leakage occurred in 6 (33%) of 18 in the non ultrasonic MTA group, 2 (11%) of 18 in the ultrasonic MTA group, and 1 (6%) of 18 in the ultrasonic MTA-composite group. There were no significant differences at 90 days. A 4-mm thickness of MTA followed with an intracanal composite resin demonstrated a significantly greater resistance to root fracture than MTA followed with gutta-percha and sealer (one-way ANOVA with Newman-Keuls multiple comparison test, p < 0.01). The MTA–gutta-percha group was not significantly different than the MTA unrestored positive control.
Influence of Ultrasound, With and Without Water Spray Cooling, on Removal of Posts Cemented With Resin or Zinc Phosphate Cements
Ângela Delfina Bittencourt Garrido, DDS, MSc, Tabajara Sabbag Fonseca, DDS, Edson Alfredo, DDS, MSc, Yara Teresinha Corrêa Silva-Sousa, DDS, MSc, PhD, and Manoel D. Sousa-Neto, DDS, MSc, PhD
The efficacy of ultrasound, with and without water spray, was evaluated in vitro on the amount of force necessary to dislodge posts cemented with resin or zinc phosphate. Forty-two samples were divided into six groups: groups 1, 2, and 3, posts cemented with zinc phosphate; groups 4, 5, and 6, posts cemented with resin (Panavia F); groups 1 and 4 (controls), no ultrasound; groups 2 and 5, ultrasound without water spray; and groups 3 and 6, ultrasound with water spray. The Instron testing machine was used. Ultrasound without water spray significantly reduced (71%) the force necessary to displace posts cemented with Panavia F (p< 0.01); however, this value was similar to the efficacy of ultrasound with water spray for posts cemented with zinc phosphate (reduction of 75%). We conclude that cooling with ultrasound interferes with the force necessary for post removal, depending on the type of cement used.
Effect of a Separated Instrument on Bacterial Penetration of Obturated Root Canals
Jeffrey L. Saunders, DDS, Paul D. Eleazer, DDS, MS, Ping Zhang, PhD, DDS, and Susanne Michalek, PhD
The aim of this study was to determine the effect a separated instrument has on the time required for bacterial penetration of obturated root canals. Twenty-six extracted human mandibular premolars with single canals were used in the study. Group 1 consisted of teeth that contained a separated size 40 Profile rotary file and were obturated with gutta-percha and zinc oxide eugenol sealer to the level of the separated file. Group 2 consisted of teeth that were similarly obturated, but without a separated file. The negative control canals were obturated and had the entire root surface sealed with nail polish. The positive controls were obturated without sealer. Streptococcus sanguis was placed in the access chamber daily, and penetration was determined when turbidity was noted in the culture broth. The results showed no significant difference between the two experimental groups.
Accidental Sodium Hypochlorite-Induced Skin Injury During Endodontic Treatment
Ahmet Serper, DDS, PhD, Murat Özbek, DDS, PhD, and Semra Çalt, DDS, PhD
A case of accidental skin injury caused by leakage of sodium hypochlorite solution from the rubber dam during root canal preparation is reported. After placement of a rubber dam and initiation of root canal treatment, the patient complained of a burning sensation with sodium hypochlorite irrigation. The complaints were ignored by the practitioner, and a skin rash developed on and around the patient’s chin, followed by scab formation. The patient required medical treatment with topical Hamamelis virginiana extract for 2 weeks, with full recovery.
Glandular Odontogenic Cyst
Phuong-Thao Tran, DDS, Charles J. Cunningham, DDS, and Ronald A. Baughman, DDS, MSD
This case report describes the clinical, radiologic, and histopathologic features of the glandular odontogenic cyst (GOC). Although a relatively rare lesion not previously reported in the endodontic literature, the GOC is recommended for inclusion in a differential diagnosis of a dentoalveolar radiolucency. The GOC is a destructive lesion that can be easily misdiagnosed microscopically as a central mucoepidermoid carcinoma.
Middle Mesial Canal of the Mandibular First Molar: A Case Report and Literature Review
Dean Baugh, DDS, and James Wallace, DDS, MDS, MSD, MS
With the advent of magnification, either by loupes or microscope, the astute clinician must be aware of recent literature that states that the mandibular first molar has a 1–15% chance of a fifth canal. This is a case report accompanied by a review of the literature that shows the unusual anatomy of the mandibular first molar.