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P. Wesselink

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Papers by P. Wesselink

The first five years. A framework for undergraduate dental education

The correlation between root canal patterns and interorificial distance in mandibular first molars

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006

The aim of this study was to investigate the relationship of the distance between mesiobuccal (MB... more The aim of this study was to investigate the relationship of the distance between mesiobuccal (MB) and mesiolingual (ML) orifices (interorificial distances) in the pulp chamber floor and the degree of canal curvature in the mandibular first molars. Study design. In this in vitro study, 102 extracted teeth were radiographed in both buccolingual (CV) and mesiodistal (PV) directions and then grouped according to the Vertucci classification. The interorificial distance was measured by the stereomicroscope method. Results. The interorificial distance was significantly higher in type IV compared to type II (Pϭ .016). In the logistic regression analysis, the increase in the degree of primary canal curvature of the ML in CV was a predictive factor for increase in the primary curvature of ML in PV (P ϭ .01). Conclusion. The interorificial distance in the pulp chamber floor and primary curvatures in CV were found to be key factors for evaluation of root canal patterns in PV.

Root filling techniques

Textbook of endodontology. - 2nd ed., 2010

Reactions of the living organism to dead and fixed dead tissue

Journal of endodontics, 1978

Two series of experiments were conducted on the reactions of the living organism when in contact ... more Two series of experiments were conducted on the reactions of the living organism when in contact with dead and fixed dead tissue. The inflammatory reaction to necrotic tissue was less severe than the reaction to fixed necrotic tissue. The results led to the tentative qonclusion that chronic periapical inflammation most likely is caused by living microorganisms.

The smear layer: a phenomenon in root canal therapy

International Endodontic Journal, 1995

Effect of sealer thickness on long?term sealing ability: a 2?year follow?up study

International Endodontic Journal, 1997

Long-term sealing ability of root-canal sealer is of clinical importance. We compared the perform... more Long-term sealing ability of root-canal sealer is of clinical importance. We compared the performance of five sealers and a dentine bonding agent, at thicknesses of 0.05 mm (thin layer) and 0.3 mm (thick layer), in 212 standard human root specimens, before and after storage in water for 2 years. Thick layers of Roth and Pulp Canal Sealer EWT (PCS-EWT) allowed more leakage than did thin layers (P = 0.0000, 0.0358 for Roth and PCS-EWT, respectively) whereas no significant difference was found between the thin and thick layers for AH26, Ketac-Endo, Sealapex and J&amp;J Bonding Agent. The pooled results of the thin and thick layers, which have clinical relevance, showed that after storing the specimens in water for 2 years, AH26, Sealapex, Ketac-Endo and PCS-EWT leaked more than before storage in water (P = 0.0008, 0.0000, 0.0035, 0.0257 for AH26, Sealapex, Ketac-Endo and PCS-EWT respectively), and that J&amp;J Bonding Agent allowed less leakage and PCS-EWT more leakage than the other four sealers (P = 0.0000).

Improving the accuracy of a fluid transport method

International Endodontic Journal, 2012

Aim To compare the sealing ability of the same root fillings when measured by a conventional flui... more Aim To compare the sealing ability of the same root fillings when measured by a conventional fluid transport method that uses water or by a modified fluid transport method that uses a wetting fluid as tracer. Methodology The amount of fluid transport along the same root fillings (AH26, cold lateral compaction of gutta-percha) was measured in a cross-over design in fluid transport setups using either water or a wetting fluid as tracer. Results A Wilcoxon signed-rank test revealed a significant difference in the amount of fluid transport measured along the same root fillings by the two fluid transport methods (P = 0.013). The fluid transport method using wetting fluid detected a significantly higher percentage of root fillings with fluid transport (P = 0.021). Conclusions Fluid transport using a wetting fluid as a tracer was more sensitive in the assessment of sealing ability of root fillings than the conventional fluid transport method using water.

The creation of virtual teeth with and without tooth pathology for a virtual learning environment in dental education

European Journal of Dental Education, 2013

Viable Bacteria in Root Dentinal Tubules of Teeth with Apical Periodontitis

Journal of Endodontics, 2001

Two sets of teeth with apical periodontitis were collected at different geographic locations to s... more Two sets of teeth with apical periodontitis were collected at different geographic locations to study the identity of bacteria left in the root dentinal tubules. Root dentin of 20 of these teeth was cultured from three locations between pulp and cementum (A, B, and C). In addition dentin from eight teeth was examined histologically. Using the culturing technique bacteria were found in 77% of the dentin samples from set 1 (Amsterdam) and in 87.5% of the dentin samples from set 2 (Glasgow). At greater distance, in layer C, from the pulp bacteria were found in 62% (13 of 21) of the dentin samples. Twenty-three percent (3 of 13) of set 1 and 25% (2 of 8) of set 2 contained >50,000 colony-forming units/mg of dentin in layer C. In layers closer to the pulp higher numbers of anaerobic bacteria and Gram-positive rods were found, as well as a larger number of bacterial species. Histological sections showed bacterial penetration in dentinal tubules in 5 of 8 teeth. In the other three teeth where the colony-forming units/mg recovered was <10,000, no histological signs of tubule penetration was seen. It seems clear that, in more than half of the infected roots, bacteria are present in the deep dentin close to the cementum and that anaerobic culturing of dentin is more sensitive than histology to detect these bacteria.

Periapical status and prevalence of endodontic treatment in an adult Dutch population

International Endodontic Journal, 1993

This study examined the prevalence of endodontic treatment in a group of 184 Dutch adults, and de... more This study examined the prevalence of endodontic treatment in a group of 184 Dutch adults, and determined the periapical status of all teeth using panoramic radiographs. The results indicate that in this group, 2.3% ofthe teeth were root-filled, and that 5.2% ofall non-endod(Hitically treated teeth showed signs of periapical pathology. Around the apices of 39.2% of the endodontically treated teeth in this survey, radiographic signs of periapical pathology were observed. Using the level ofthe root canal filling as a criterion for evaluating the quality of the root canal treatment, 50.6% of the endodontic treatments were qualified as inadequate. There was a significant correlation hetween the presence of periapical pathology and underfilling of the root canal(s). 44.6% of the patient sample had at least one tooth with radiographic signs of periapical pathology, indicating a substantial future need for endodontic treatment.

The Influence of 1-Hydroxyethylidene-l,l-Bisphosphonate (HEBP) on Dental Root Resorption in the Mouse

Calcified Tissue Int, 1989

It has been hypothesized that phagocy-tosis of a layer of mineralized material which is sometimes... more It has been hypothesized that phagocy-tosis of a layer of mineralized material which is sometimes deposited along the root surface following trauma is an important factor in the initiation of the resorption of teeth [1]. To test this hypothesis, freezing of the mouse incisor periodontium was used as a model where deposition of mineral was prevented by the systemic administration of 1-hydroxyethylidene-l,l-bisphosphonate (HEBP, 10 mg P/kg b.w.) for time periods varying from 2 to 31 days. The animals were killed either 24 hours or 1 month after the last injection and their mandibles were processed for light microscopy. In the HEBP-treated animals, killed 24 hours after the last injection , no mineralized material had been deposited along the root surface, and very little resorption was seen. Large amounts of bone matrix were deposited in the intraperiodontal space (often causing localized ankylosis). In HEBP-treated animals killed 1 month after the last injection, again no layer of mineralized material along the root surface was seen, but now root resorption had become manifest, occupying up to 40% of the cement surface. This occurred irrespective of the duration of HEBP administration. In the saline-treated animals, extensive resorption of the incisor was noted (up to 90% of its surface). It is concluded that the layer of min-eralized material deposited after the periodontium is frozen does not play a decisive part in the onset of root resorption. HEBP treatment slows down root resorption but does not prevent it.

Comparison of Five Cone Beam Computed Tomography Systems for the Detection of Vertical Root Fractures

Journal of Endodontics, 2010

Introduction: This study compared the accuracy of cone beam computed tomography (CBCT) scans made... more Introduction: This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth (premolar/molar) on detection accuracy. Methods: Eighty endodontically prepared teeth were divided into four groups and placed in dry mandibles. The teeth in groups Fr-F and Fr-NF were artificially fractured; those in groups control-F and control-NF were not. Groups Fr-F and control-F were root filled. CBCT scans were made using five different commercial CBCT systems. Two observers evaluated images in axial, coronal, and sagittal reconstruction planes. Results: There was a significant difference in detection accuracy among the five systems (p = 0.00001). The presence of RCF did not influence sensitivity (p = 0.16), but it reduced specificity (p = 0.003). Axial slices were significantly more accurate than sagittal and coronal slices (p = 0.0001) in detecting VRF in all systems. Significantly more VRFs were detected among molars than premolars (p = 0.0001). Conclusions: RCF presence reduced specificity in all systems (p = 0.003) but did not influence accuracy (p = 0.79) except in one system (p = 0.012). Axial slices were the most accurate in detecting VRFs (p = 0.0001).

Accuracy of Periapical Radiography and Cone-Beam Computed Tomography Scans in Diagnosing Apical Periodontitis Using Histopathological Findings as a Gold Standard

Journal of Endodontics, 2009

Introduction: The aim of this study was to evaluate the accuracy of two imaging methods in diagno... more Introduction: The aim of this study was to evaluate the accuracy of two imaging methods in diagnosing apical periodontitis (AP) using histopathological findings as a gold standard. Methods: The periapex of 83 treated or untreated roots of dogs' teeth was examined using periapical radiography (PR), cone-beam computed tomography (CBCT) scans, and histology. Sensitivity, specificity, predictive values, and accuracy of PR and CBCT diagnosis were calculated. Results: PR detected AP in 71% of roots, a CBCT scan detected AP in 84%, and AP was histologically diagnosed in 93% (p = 0.001). Overall, sensitivity was 0.77 and 0.91 for PR and CBCT, respectively. Specificity was 1 for both. Negative predictive value was 0.25 and 0.46 for PR and CBCT, respectively. Positive predictive value was 1 for both. Diagnostic accuracy (true positives + true negatives) was 0.78 and 0.92 for PR and CBCT (p = 0.028), respectively. Conclusion: A CBCT scan was more sensitive in detecting AP compared with PR, which was more likely to miss AP when it was still present.

The prevalence and distribution of rests of Malassez in the mouse molar and their possible role in repair and maintenance of the periodontal ligament

Archives of Oral Biology, 1993

This study sought to determine the prevalence and distribution of these rests under normal condit... more This study sought to determine the prevalence and distribution of these rests under normal conditions and after giving I-hydroxyethylidene-l,l-bisphosphonate (HEBP), a drug that interferes with homeostasis in the periodontal ligament. Normally the rests of Malassez were equally distributed on all root aspects with the exception of the mesial of the mesial root of the first mandibular molar. With increasing age their number decreased. A similar distribution was seen in the animals treated with the bisphosphonate, in which there was a severe reduction in width of the periodontal ligament, at several sites resulting in ankylosis. After discontinuing HEBP the normal width of the periodontal ligament space was restored. Repair was characterized by root resorption, elimination of ankylosis, cementum formation and regeneration of ligament. These processes seemed to have no connection with the prevalence and distribution of rests of Malassez. It is concluded that rests of Malassez are unlikely to play an important part in the homeostasis of periodontal ligament and do not seem to be a prerequisite for its repair and maintenance.

Detection of Vertical Root Fractures in Endodontically Treated Teeth by a Cone Beam Computed Tomography Scan

Journal of Endodontics, 2009

Our aim was to compare the accuracy of cone beam computed tomography (CBCT) scans and periapical ... more Our aim was to compare the accuracy of cone beam computed tomography (CBCT) scans and periapical radiographs (PRs) in detecting vertical root fractures (VRFs) and to assess the influence of root canal filling (RCF) on fracture visibility. Eighty teeth were endodontically prepared and divided into four groups. The teeth in groups A and B were artificially fractured, and teeth in groups C and D were not. Groups A and C were root filled. Four observers evaluated the CBCT scans and PR images. Sensitivity and specificity for VRF detection of CBCT were 79.4% and 92.5% and for PR were 37.1% and 95%, respectively. The specificity of CBCT was reduced (p = 0.032) by the presence of RCF, but its overall accuracy was not influenced (p = 0.654). Both the sensitivity (p = 0.006) and overall accuracy (p = 0.008) of PRs were reduced by the presence of RCF. The results showed an overall higher accuracy for CBCT (0.86) scans than PRs (0.66) for detecting VRF.

Effect of a two-step placement procedure on the dislocation resistance of a methacrylate resin-based root canal sealer: a proof of concept

The journal of adhesive dentistry, 2014

To investigate whether the placement of a methacrylate root canal sealer or a conventional epoxy ... more To investigate whether the placement of a methacrylate root canal sealer or a conventional epoxy root canal sealer in two steps increases their dislocation resistance when compared to a one-step placement procedure. Eighty single-rooted teeth were randomly allocated to 4 groups (n=20). All canals were instrumented to size 40, 0.06 taper and irrigated according to a standardized protocol. Root canal filling was conducted as follows: group 1: methacrylate sealer placed in two steps; group 2: methacrylate sealer placed in one step; group 3: epoxy sealer placed in two steps; group 4: epoxy sealer placed in one step. After setting, thin slices at different root levels were obtained and submitted to push-out testing. RESULTS were analyzed with non-parametric tests to compare the two-step procedures to their one-step counterparts. Failure modes were determined by stereomicroscopy. Random untested methacrylate sealer specimens were also examined with scanning electron microscopy. At each ro...

Effect of thickness on the sealing ability of some root canal sealers

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 1995

A fluid transport model study was used to evaluate the sealing ability of five root canal sealers... more A fluid transport model study was used to evaluate the sealing ability of five root canal sealers, AH 26, Sealapex, Ketac Endo, Roth, and Kerr EWT, and a dental bonding agent at thicknesses of 0.05 mm (thin layer) and 0.3 mm (thick layer) with 270 standard human root sections obturated with sealer combined with standard gutta-percha cylinders. AH26 and Sealapex sealed more tightly in thick layers, whereas Ketac Endo, Johnson and Johnson Bonding Agent, Roth, and Kerr EWT sealed more tightly in thin layers. In thin layers J&amp;J Bonding sealed more tightly than any other sealer tested. In thick layers AH 26 and Sealapex sealed more tightly than Ketac Endo and J&amp;J Bonding Agent, and these sealed more tightly than Roth and Kerr EWT. These findings indicate that the thickness of the sealer layer significantly influences the sealing of a root canal filling and that the influence of thickness varies depending on the type of sealer.

Bisphosphonates and their clinical implications in endodontic therapy

International Endodontic Journal, 2012

This review gives an overview of the factors that may play a role in the development of osteonecr... more This review gives an overview of the factors that may play a role in the development of osteonecrosis of the jaw in patients treated with bisphosphonates (BPs) and undergoing nonsurgical endodontic treatment as well as some recommendations for its prevention. BPs are a widely prescribed group of drugs for diverse bone diseases. The occasional but devastating adverse effect of these drugs has been described as bisphosphonate-related osteonecrosis of the jaw (BRONJ). As this condition is debilitating and difficult to treat, all efforts should be made to prevent its occurence in patients at risk. The main triggering event is considered to be dental extraction. Even though nonsurgical endodontic treatment appears to be a relatively safe procedure, care remains essential. After an overview of this class of drugs, the clinical presentation, epidemiology and pathogenesis of BRONJ, as well as the possible risk factors associated with its development after nonsurgical endodontic treatment will be described. Finally, several strategies will be proposed for the prevention of BRONJ during nonsurgical endodontic treatment.

The Ability of Different Nickel-Titanium Rotary Instruments To Induce Dentinal Damage During Canal Preparation

Journal of Endodontics, 2009

The purpose of this study was to compare the incidence of dentinal defects (fractures and craze l... more The purpose of this study was to compare the incidence of dentinal defects (fractures and craze lines) after canal preparation with different nickel-titanium rotary files. Two hundred sixty mandibular premolars were selected. Forty teeth were left unprepared (n ϭ 40). The other teeth were prepared either with manual Flexofiles (n ϭ 20) or with different rotary files systems: ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland), ProFile (Dentsply-Maillefer), SystemGT (Dentsply-Maillefer), or S-ApeX (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n ϭ 50 each). Roots were then sectioned 3, 6, and 9 mm from the apex and observed under a microscope. The presence of dentinal defects was noted. There was a significant difference in the appearance of defects between the groups (p Ͻ 0.05). No defects were found in the unprepared roots and those prepared with hand files and S-ApeX. ProTaper, ProFile, and GT preparations resulted in dentinal defects in 16%, 8%, and 4% of teeth, respectively. Some endodontic preparation methods might damage the root and induce dentinal defects.

Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard

by Francisco Wanderley Garcia Paula-Silva and P. Wesselink

Journal of …, 2009

PR detected AP in 71% of roots, a CBCT scan detected AP in 84%, and AP was histologically diagnos... more

The first five years. A framework for undergraduate dental education

The correlation between root canal patterns and interorificial distance in mandibular first molars

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006

The aim of this study was to investigate the relationship of the distance between mesiobuccal (MB... more The aim of this study was to investigate the relationship of the distance between mesiobuccal (MB) and mesiolingual (ML) orifices (interorificial distances) in the pulp chamber floor and the degree of canal curvature in the mandibular first molars. Study design. In this in vitro study, 102 extracted teeth were radiographed in both buccolingual (CV) and mesiodistal (PV) directions and then grouped according to the Vertucci classification. The interorificial distance was measured by the stereomicroscope method. Results. The interorificial distance was significantly higher in type IV compared to type II (Pϭ .016). In the logistic regression analysis, the increase in the degree of primary canal curvature of the ML in CV was a predictive factor for increase in the primary curvature of ML in PV (P ϭ .01). Conclusion. The interorificial distance in the pulp chamber floor and primary curvatures in CV were found to be key factors for evaluation of root canal patterns in PV.

Root filling techniques

Textbook of endodontology. - 2nd ed., 2010

Reactions of the living organism to dead and fixed dead tissue

Journal of endodontics, 1978

Two series of experiments were conducted on the reactions of the living organism when in contact ... more Two series of experiments were conducted on the reactions of the living organism when in contact with dead and fixed dead tissue. The inflammatory reaction to necrotic tissue was less severe than the reaction to fixed necrotic tissue. The results led to the tentative qonclusion that chronic periapical inflammation most likely is caused by living microorganisms.

The smear layer: a phenomenon in root canal therapy

International Endodontic Journal, 1995

Effect of sealer thickness on long?term sealing ability: a 2?year follow?up study

International Endodontic Journal, 1997

Long-term sealing ability of root-canal sealer is of clinical importance. We compared the perform... more Long-term sealing ability of root-canal sealer is of clinical importance. We compared the performance of five sealers and a dentine bonding agent, at thicknesses of 0.05 mm (thin layer) and 0.3 mm (thick layer), in 212 standard human root specimens, before and after storage in water for 2 years. Thick layers of Roth and Pulp Canal Sealer EWT (PCS-EWT) allowed more leakage than did thin layers (P = 0.0000, 0.0358 for Roth and PCS-EWT, respectively) whereas no significant difference was found between the thin and thick layers for AH26, Ketac-Endo, Sealapex and J&amp;J Bonding Agent. The pooled results of the thin and thick layers, which have clinical relevance, showed that after storing the specimens in water for 2 years, AH26, Sealapex, Ketac-Endo and PCS-EWT leaked more than before storage in water (P = 0.0008, 0.0000, 0.0035, 0.0257 for AH26, Sealapex, Ketac-Endo and PCS-EWT respectively), and that J&amp;J Bonding Agent allowed less leakage and PCS-EWT more leakage than the other four sealers (P = 0.0000).

Improving the accuracy of a fluid transport method

International Endodontic Journal, 2012

Aim To compare the sealing ability of the same root fillings when measured by a conventional flui... more Aim To compare the sealing ability of the same root fillings when measured by a conventional fluid transport method that uses water or by a modified fluid transport method that uses a wetting fluid as tracer. Methodology The amount of fluid transport along the same root fillings (AH26, cold lateral compaction of gutta-percha) was measured in a cross-over design in fluid transport setups using either water or a wetting fluid as tracer. Results A Wilcoxon signed-rank test revealed a significant difference in the amount of fluid transport measured along the same root fillings by the two fluid transport methods (P = 0.013). The fluid transport method using wetting fluid detected a significantly higher percentage of root fillings with fluid transport (P = 0.021). Conclusions Fluid transport using a wetting fluid as a tracer was more sensitive in the assessment of sealing ability of root fillings than the conventional fluid transport method using water.

The creation of virtual teeth with and without tooth pathology for a virtual learning environment in dental education

European Journal of Dental Education, 2013

Viable Bacteria in Root Dentinal Tubules of Teeth with Apical Periodontitis

Journal of Endodontics, 2001

Two sets of teeth with apical periodontitis were collected at different geographic locations to s... more Two sets of teeth with apical periodontitis were collected at different geographic locations to study the identity of bacteria left in the root dentinal tubules. Root dentin of 20 of these teeth was cultured from three locations between pulp and cementum (A, B, and C). In addition dentin from eight teeth was examined histologically. Using the culturing technique bacteria were found in 77% of the dentin samples from set 1 (Amsterdam) and in 87.5% of the dentin samples from set 2 (Glasgow). At greater distance, in layer C, from the pulp bacteria were found in 62% (13 of 21) of the dentin samples. Twenty-three percent (3 of 13) of set 1 and 25% (2 of 8) of set 2 contained >50,000 colony-forming units/mg of dentin in layer C. In layers closer to the pulp higher numbers of anaerobic bacteria and Gram-positive rods were found, as well as a larger number of bacterial species. Histological sections showed bacterial penetration in dentinal tubules in 5 of 8 teeth. In the other three teeth where the colony-forming units/mg recovered was <10,000, no histological signs of tubule penetration was seen. It seems clear that, in more than half of the infected roots, bacteria are present in the deep dentin close to the cementum and that anaerobic culturing of dentin is more sensitive than histology to detect these bacteria.

Periapical status and prevalence of endodontic treatment in an adult Dutch population

International Endodontic Journal, 1993

This study examined the prevalence of endodontic treatment in a group of 184 Dutch adults, and de... more This study examined the prevalence of endodontic treatment in a group of 184 Dutch adults, and determined the periapical status of all teeth using panoramic radiographs. The results indicate that in this group, 2.3% ofthe teeth were root-filled, and that 5.2% ofall non-endod(Hitically treated teeth showed signs of periapical pathology. Around the apices of 39.2% of the endodontically treated teeth in this survey, radiographic signs of periapical pathology were observed. Using the level ofthe root canal filling as a criterion for evaluating the quality of the root canal treatment, 50.6% of the endodontic treatments were qualified as inadequate. There was a significant correlation hetween the presence of periapical pathology and underfilling of the root canal(s). 44.6% of the patient sample had at least one tooth with radiographic signs of periapical pathology, indicating a substantial future need for endodontic treatment.

The Influence of 1-Hydroxyethylidene-l,l-Bisphosphonate (HEBP) on Dental Root Resorption in the Mouse

Calcified Tissue Int, 1989

It has been hypothesized that phagocy-tosis of a layer of mineralized material which is sometimes... more It has been hypothesized that phagocy-tosis of a layer of mineralized material which is sometimes deposited along the root surface following trauma is an important factor in the initiation of the resorption of teeth [1]. To test this hypothesis, freezing of the mouse incisor periodontium was used as a model where deposition of mineral was prevented by the systemic administration of 1-hydroxyethylidene-l,l-bisphosphonate (HEBP, 10 mg P/kg b.w.) for time periods varying from 2 to 31 days. The animals were killed either 24 hours or 1 month after the last injection and their mandibles were processed for light microscopy. In the HEBP-treated animals, killed 24 hours after the last injection , no mineralized material had been deposited along the root surface, and very little resorption was seen. Large amounts of bone matrix were deposited in the intraperiodontal space (often causing localized ankylosis). In HEBP-treated animals killed 1 month after the last injection, again no layer of mineralized material along the root surface was seen, but now root resorption had become manifest, occupying up to 40% of the cement surface. This occurred irrespective of the duration of HEBP administration. In the saline-treated animals, extensive resorption of the incisor was noted (up to 90% of its surface). It is concluded that the layer of min-eralized material deposited after the periodontium is frozen does not play a decisive part in the onset of root resorption. HEBP treatment slows down root resorption but does not prevent it.

Comparison of Five Cone Beam Computed Tomography Systems for the Detection of Vertical Root Fractures

Journal of Endodontics, 2010

Introduction: This study compared the accuracy of cone beam computed tomography (CBCT) scans made... more Introduction: This study compared the accuracy of cone beam computed tomography (CBCT) scans made by five different systems in detecting vertical root fractures (VRFs). It also assessed the influence of the presence of root canal filling (RCF), CBCT slice orientation selection, and the type of tooth (premolar/molar) on detection accuracy. Methods: Eighty endodontically prepared teeth were divided into four groups and placed in dry mandibles. The teeth in groups Fr-F and Fr-NF were artificially fractured; those in groups control-F and control-NF were not. Groups Fr-F and control-F were root filled. CBCT scans were made using five different commercial CBCT systems. Two observers evaluated images in axial, coronal, and sagittal reconstruction planes. Results: There was a significant difference in detection accuracy among the five systems (p = 0.00001). The presence of RCF did not influence sensitivity (p = 0.16), but it reduced specificity (p = 0.003). Axial slices were significantly more accurate than sagittal and coronal slices (p = 0.0001) in detecting VRF in all systems. Significantly more VRFs were detected among molars than premolars (p = 0.0001). Conclusions: RCF presence reduced specificity in all systems (p = 0.003) but did not influence accuracy (p = 0.79) except in one system (p = 0.012). Axial slices were the most accurate in detecting VRFs (p = 0.0001).

Accuracy of Periapical Radiography and Cone-Beam Computed Tomography Scans in Diagnosing Apical Periodontitis Using Histopathological Findings as a Gold Standard

Journal of Endodontics, 2009

Introduction: The aim of this study was to evaluate the accuracy of two imaging methods in diagno... more Introduction: The aim of this study was to evaluate the accuracy of two imaging methods in diagnosing apical periodontitis (AP) using histopathological findings as a gold standard. Methods: The periapex of 83 treated or untreated roots of dogs' teeth was examined using periapical radiography (PR), cone-beam computed tomography (CBCT) scans, and histology. Sensitivity, specificity, predictive values, and accuracy of PR and CBCT diagnosis were calculated. Results: PR detected AP in 71% of roots, a CBCT scan detected AP in 84%, and AP was histologically diagnosed in 93% (p = 0.001). Overall, sensitivity was 0.77 and 0.91 for PR and CBCT, respectively. Specificity was 1 for both. Negative predictive value was 0.25 and 0.46 for PR and CBCT, respectively. Positive predictive value was 1 for both. Diagnostic accuracy (true positives + true negatives) was 0.78 and 0.92 for PR and CBCT (p = 0.028), respectively. Conclusion: A CBCT scan was more sensitive in detecting AP compared with PR, which was more likely to miss AP when it was still present.

The prevalence and distribution of rests of Malassez in the mouse molar and their possible role in repair and maintenance of the periodontal ligament

Archives of Oral Biology, 1993

This study sought to determine the prevalence and distribution of these rests under normal condit... more This study sought to determine the prevalence and distribution of these rests under normal conditions and after giving I-hydroxyethylidene-l,l-bisphosphonate (HEBP), a drug that interferes with homeostasis in the periodontal ligament. Normally the rests of Malassez were equally distributed on all root aspects with the exception of the mesial of the mesial root of the first mandibular molar. With increasing age their number decreased. A similar distribution was seen in the animals treated with the bisphosphonate, in which there was a severe reduction in width of the periodontal ligament, at several sites resulting in ankylosis. After discontinuing HEBP the normal width of the periodontal ligament space was restored. Repair was characterized by root resorption, elimination of ankylosis, cementum formation and regeneration of ligament. These processes seemed to have no connection with the prevalence and distribution of rests of Malassez. It is concluded that rests of Malassez are unlikely to play an important part in the homeostasis of periodontal ligament and do not seem to be a prerequisite for its repair and maintenance.

Detection of Vertical Root Fractures in Endodontically Treated Teeth by a Cone Beam Computed Tomography Scan

Journal of Endodontics, 2009

Our aim was to compare the accuracy of cone beam computed tomography (CBCT) scans and periapical ... more Our aim was to compare the accuracy of cone beam computed tomography (CBCT) scans and periapical radiographs (PRs) in detecting vertical root fractures (VRFs) and to assess the influence of root canal filling (RCF) on fracture visibility. Eighty teeth were endodontically prepared and divided into four groups. The teeth in groups A and B were artificially fractured, and teeth in groups C and D were not. Groups A and C were root filled. Four observers evaluated the CBCT scans and PR images. Sensitivity and specificity for VRF detection of CBCT were 79.4% and 92.5% and for PR were 37.1% and 95%, respectively. The specificity of CBCT was reduced (p = 0.032) by the presence of RCF, but its overall accuracy was not influenced (p = 0.654). Both the sensitivity (p = 0.006) and overall accuracy (p = 0.008) of PRs were reduced by the presence of RCF. The results showed an overall higher accuracy for CBCT (0.86) scans than PRs (0.66) for detecting VRF.

Effect of a two-step placement procedure on the dislocation resistance of a methacrylate resin-based root canal sealer: a proof of concept

The journal of adhesive dentistry, 2014

To investigate whether the placement of a methacrylate root canal sealer or a conventional epoxy ... more To investigate whether the placement of a methacrylate root canal sealer or a conventional epoxy root canal sealer in two steps increases their dislocation resistance when compared to a one-step placement procedure. Eighty single-rooted teeth were randomly allocated to 4 groups (n=20). All canals were instrumented to size 40, 0.06 taper and irrigated according to a standardized protocol. Root canal filling was conducted as follows: group 1: methacrylate sealer placed in two steps; group 2: methacrylate sealer placed in one step; group 3: epoxy sealer placed in two steps; group 4: epoxy sealer placed in one step. After setting, thin slices at different root levels were obtained and submitted to push-out testing. RESULTS were analyzed with non-parametric tests to compare the two-step procedures to their one-step counterparts. Failure modes were determined by stereomicroscopy. Random untested methacrylate sealer specimens were also examined with scanning electron microscopy. At each ro...

Effect of thickness on the sealing ability of some root canal sealers

Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 1995

A fluid transport model study was used to evaluate the sealing ability of five root canal sealers... more A fluid transport model study was used to evaluate the sealing ability of five root canal sealers, AH 26, Sealapex, Ketac Endo, Roth, and Kerr EWT, and a dental bonding agent at thicknesses of 0.05 mm (thin layer) and 0.3 mm (thick layer) with 270 standard human root sections obturated with sealer combined with standard gutta-percha cylinders. AH26 and Sealapex sealed more tightly in thick layers, whereas Ketac Endo, Johnson and Johnson Bonding Agent, Roth, and Kerr EWT sealed more tightly in thin layers. In thin layers J&amp;J Bonding sealed more tightly than any other sealer tested. In thick layers AH 26 and Sealapex sealed more tightly than Ketac Endo and J&amp;J Bonding Agent, and these sealed more tightly than Roth and Kerr EWT. These findings indicate that the thickness of the sealer layer significantly influences the sealing of a root canal filling and that the influence of thickness varies depending on the type of sealer.

Bisphosphonates and their clinical implications in endodontic therapy

International Endodontic Journal, 2012

This review gives an overview of the factors that may play a role in the development of osteonecr... more This review gives an overview of the factors that may play a role in the development of osteonecrosis of the jaw in patients treated with bisphosphonates (BPs) and undergoing nonsurgical endodontic treatment as well as some recommendations for its prevention. BPs are a widely prescribed group of drugs for diverse bone diseases. The occasional but devastating adverse effect of these drugs has been described as bisphosphonate-related osteonecrosis of the jaw (BRONJ). As this condition is debilitating and difficult to treat, all efforts should be made to prevent its occurence in patients at risk. The main triggering event is considered to be dental extraction. Even though nonsurgical endodontic treatment appears to be a relatively safe procedure, care remains essential. After an overview of this class of drugs, the clinical presentation, epidemiology and pathogenesis of BRONJ, as well as the possible risk factors associated with its development after nonsurgical endodontic treatment will be described. Finally, several strategies will be proposed for the prevention of BRONJ during nonsurgical endodontic treatment.

The Ability of Different Nickel-Titanium Rotary Instruments To Induce Dentinal Damage During Canal Preparation

Journal of Endodontics, 2009

The purpose of this study was to compare the incidence of dentinal defects (fractures and craze l... more The purpose of this study was to compare the incidence of dentinal defects (fractures and craze lines) after canal preparation with different nickel-titanium rotary files. Two hundred sixty mandibular premolars were selected. Forty teeth were left unprepared (n ϭ 40). The other teeth were prepared either with manual Flexofiles (n ϭ 20) or with different rotary files systems: ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland), ProFile (Dentsply-Maillefer), SystemGT (Dentsply-Maillefer), or S-ApeX (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n ϭ 50 each). Roots were then sectioned 3, 6, and 9 mm from the apex and observed under a microscope. The presence of dentinal defects was noted. There was a significant difference in the appearance of defects between the groups (p Ͻ 0.05). No defects were found in the unprepared roots and those prepared with hand files and S-ApeX. ProTaper, ProFile, and GT preparations resulted in dentinal defects in 16%, 8%, and 4% of teeth, respectively. Some endodontic preparation methods might damage the root and induce dentinal defects.

Accuracy of periapical radiography and cone-beam computed tomography scans in diagnosing apical periodontitis using histopathological findings as a gold standard

by Francisco Wanderley Garcia Paula-Silva and P. Wesselink

Journal of …, 2009

PR detected AP in 71% of roots, a CBCT scan detected AP in 84%, and AP was histologically diagnos... more