Pulpless Teeth Research Articles

In vivo qualitative analysis of the biocompatibility of different cyanoacrylate-based adhesives

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control)--distilled water, B--cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D--alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.

Ability of root canal antiseptics used in dental practice to induce chromosome aberrations in human dental pulp cells

Root canal antiseptics are topically applied to root canals within the pulpless teeth to treat the root canal and periapical infections. Because the antiseptics that are applied to root canals can penetrate through dentin or leak out through an apical foramen into the periodontium and distribute by the systemic circulation, it is important to study the safety of these antiseptics. In the present study, we examined the ability to induce chromosome aberrations in human dental pulp cells of five root canal antiseptics, namely, carbol camphor (CC), camphorated p-monochlorophenol (CMCP), formocresol (FC), calcium hydroxide, and iodoform which are most commonly used in dental practice. Statistically significant increases in the levels of chromosome aberrations were induced by CC, FC, or iodoform in a concentration-dependent manner. Conversely, CMCP and calcium hydroxide failed to induce chromosome aberrations in the absence or presence of exogenous metabolic activation. The percentages of cells with polyploid or endoreduplication were enhanced by FC or iodoform. Our results indicate that the root canal antiseptics that exhibited a positive response are potentially genotoxic to human cells.

Use of MTA for orthograde obturation of nonvital teeth with open apices: report of two cases

The purpose of this report is to present the treatment of 2 immature necrotic permanent incisors with the use of apical plugs of mineral trioxide aggregate (MTA) for apexification. With this technique, MTA mixture is used to create an artificial stop against which to condense gutta-percha in pulpless teeth with open apices. The report of these cases confirms that MTA acts an apical barrier and can be considered as an effective material to support regeneration of apical tissue in immature necrotic teeth. The treated teeth were asymptomatic, and radiographic follow-ups showed healing of periradicular tissues and new hard tissue formation in the apical area of the affected teeth.

Clinical evaluation of pulpless teeth restored with conventionally cemented zirconia posts: A pilot study

Clinical evaluation of pulpless teeth restored with conventionally cemented zirconia posts: A pilot study

The nursing cooperation of Metapex paste in apexification of traumatic apices of pulpless antetior teeth

目的 探讨注射型Metapex糊剂在外伤性前牙根尖诱导术中的护理配合.方法 对50例72颗外伤后根尖未发育完成的前牙根尖诱导术的术前、术中、术后护理操作进行分析和总结.结果 充分的术前准备,细致默契的术中配合,严格执行无菌操作及完善的术后追踪、随访观察,做好卫生宣教及注意事项,是根尖诱导成形术成功的重要环节.结论 应用注射型Metapex糊剂使无菌操作严密且方便,提高了根尖诱导术的治疗质量,增加了治疗的成功率,是目前较理想的根尖诱导材料。

Clinical evaluation of pulpless teeth restored with conventionally cemented zirconia posts: A pilot study

Adhesive resin cements are commonly used to lute all-ceramic posts despite limited scientific data on the clinical effectiveness of using bonding agents within prepared root canals. The purpose of this study was to retrospectively evaluate the clinical performance of conventionally cemented zirconia posts. Loss of retention, fracture of posts, and fracture of teeth were evaluated. Thirty pulpless teeth in 22 patients were treated with zirconia posts. With the exception of 3 situations in which posts were inserted directly and the access openings were closed with composite resin, teeth were restored with indirectly fabricated post-and-core foundations made from zirconia posts (Cerapost or Cosmopost) combined with heat-pressed ceramic cores (IPS Empress Cosmo) and ceramic crowns (IPS Empress II). Restorations (posts and crowns) were cemented with glass-ionomer cement (KetacCem) or resin-modified glass-ionomer cement (ProTec Cem) and reevaluated, retrospectively, for failures such as loss of retention or fractures. Data were reported using descriptive statistics. The mean observation period was 29 months (range 8-44 months). No loss of retention or fracture of any restoration was observed. Although this study involved a relatively short observation period, there were no signs of failure of conventionally cemented zirconia posts with ceramic crowns.

Endotoxin Content in Endodontically Involved Teeth

Fluid was aspirated from the root canals of 40 endodontically involved teeth. This fluid was assayed for endotoxin with the limulus lysate test. Pulpless teeth contained greater concentrations of endotoxin than those with vital pulps. Symptomatic teeth also contained more endotoxin than asymptomatic teeth.

Development of Bonding System for Resin Core Construction by M.OMEGA.A Adhesive

We designed self-etching primers consisting of a series of four N-methacryloyl-omega-amino acids, MomegaA, of different methylene chain numbers for resin core construction. The interacted amount of MomegaA's carboxylic acid with root or crown dentin apatite was determined, and its effects on dentin bond durability examined. The addition of both dentin particles to the MomegaA solutions caused the carbonyl carbon peak of carboxylic acid in MomegaA to shift to a lower field, chiefly because of an acid-base interaction between carboxylic acid and calcium. Then, as the pKa value of MomegaA's carboxylic acid increased, the amount of carboxylic acid that interacted with calcium decreased. In terms of dentin bonding durability, the four tested MomegaA adhesives provided noticeably higher bond strengths of resin to root or crown dentin than ED Primer II. Therefore, from the perspective of restoring pulpless teeth with minimal intervention, carboxylated MomegaA adhesives seemed to be very useful as functional monomers for self-etching primers.

Flare-ups Incidence and Severity after Using Calcium Hydroxide as an Intra Canal Dressing

INTRODUCTION: Acute pain and swelling following endodontic treatment are challenges for patients and dentists. According to previous studies, the incidence of flare-ups increases after endodontic treatment of teeth with necrotic pulp. Calcium hydroxide is currently used as a multipotential medicament in root canal therapy. The aim of this study was to evaluate the incidence and severity of flare-ups after treatment of pulpless teeth using calcium hydroxide as an intracanal dressing. MATERIALS AND METHODS: Sixty patients with single root necrotic teeth participated in this study. These patients were randomly divided into three groups of twenty. The patients in group A were treated in a single-visit approach, in group B with a two-visit approach without any intracanal dressing and in group C with a two-visit approach using calcium hydroxide as an intracanal dressing for one week. All of the patients were followed for 72 h after each treatment session. The information about the incidence and severity of pain and swelling was recorded in tables, using a modified visual analogue scale for pain severity measurement and a scale with four degree for measuring the severity of swelling. The data were analyzed by chi-square test and GENMODE procedure. RESULTS: The incidence of pain showed to be the highest in group B and the lowest in group C. These differences were statistically significant. There was no significant difference in the severity of pain after the first visit between groups B and C; however, the severity of pain was significantly lower in group C after the second visit. The incidence of pain in group C was significantly lower than that in group A, but there was no significant difference in the severity of pain between these two groups. There was no significant difference in the incidence and severity of swelling among the three groups. CONCLUSION: It is concluded that calcium hydroxide as an intracanal dressing could be effective to decrease the postoperative pain and swelling. Therefore it is recommended to use calcium hydroxide as an interappointment dressing in necrotic teeth.

Fracture resistance of pulpless teeth restored with post-cores and crowns

The present study was designed to test the null hypothesis that there is no difference in the fracture resistance of pulpless teeth restored with different types of post-core systems and full coverage crowns. Extracted human upper premolars were restored with a fiber post, prefabricated metallic post or cast metallic post-core. Teeth with full crown preparations without post-core restorations served as a control. All teeth were restored with full coverage crowns. A 90-degree vertical or 45-degree oblique load was applied to the restored teeth with a crosshead speed of 0.5 mm/min, and the fracture loads and mode of fracture were recorded. Under the condition of vertical loading, the fracture load of teeth restored with the cast metallic post-cores was greatest among the groups (two-factor factorial ANOVA and Scheffe's F test, P<0.05). All fractures in teeth restored with all types of post-core systems propagated in the middle portions of roots, including the apices of the posts. Under the condition of oblique loading, the fracture load of teeth restored with pre-fabricated metallic posts was significantly smaller than that in other groups. Two-thirds of fractures in the fiber post group propagated within the cervical area, while most fractures in other groups extended beyond the middle of the roots. From the results of the present investigations, it was concluded that under the conditions of vertical and oblique loadings, the combination of a fiber post and composite resin core with a full cast crown is most protective of the remaining tooth structure.

Single Mucoperiosteal Flap for Oronasal Fistula Repair

Surgical endodontic therapy (apical surgery) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal. These procedures are performed through a trans-osseous approach. Terminology pertinent to this article include: apical (periapical) curettage--a surgical procedure to remove diseased tissue from the alveolar bone in the apical region of a pulpless tooth; apical cyst--a cyst in bone at the apex of a pulpless tooth. It is believed that such cysts arise after the death of the pulp from noxious physical, chemical, or bacterial stimulation of epithelial rests of Malassez; apicoectomy (apical resection) amputation of the apical portion of the root and removal of soft tissue in the bone; epithelial rests of Malassez--cords, strands, or clusters of ectodermal cells in the periodontal ligament (or sometimes alveolar bone) derived from remnants of Hertwigs epithelial root sheath. These cells frequently begin proliferating when inflammation occurs in the periodontal ligament and are believed to be responsible for the genesis of the epithelial lining of apical cysts.

Resistance to cyclic fatigue of pulpless teeth with flared root canals restored with different post-and-core materials

To investigate the resistance to cyclic fatigue of maxillary incisors with flared canals restored with different post-and-core materials. Thirty human maxillary central incisors were assigned randomly to two main groups (non-ferrule and 1-mm ferrule) of 15. Each main group was then divided into 3 groups of 5 specimens and restored with custom cast post-and-core (MPC), resin composite post-and-core (RCP), and resin composite core combined with prefabricated carbon fiber post (FRC), respectively. Every group was subjected to a cyclic fatigue test, and recorded the numbers of load cycles that occurred tooth fracture. All data were analyzed with two-way ANOVA and the Tukey HSD test at alpha = 0.05. FRC revealed significantly higher fatigue strength than the other groups (P < 0.05). Preparing a dentin ferrule increased significantly fatigue resistance (P < 0.05). The favorable (retrieval) fracture pattern of the tested specimens was discovered only in RCP. Using FRC may get a long fatigue life in restoring pulpless teeth with flared canals. Dentin ferrule preparation is necessary to enhance resistance of the restorations to cyclic fatigue.

New Effective Technique of Bleaching Pulpless Teeth

New Effective Technique of Bleaching Pulpless Teeth

Evaluation of biocompatibility of sodium perborate and 30% hydrogen peroxide using the analysis of the adherence capacity and morphology of macrophages

The purpose of this study was to evaluate the biocompatibility of the most used bleaching materials for pulpless teeth, sodium perborate and 30% hydrogen peroxide, in an experimental model of macrophages, through analysis of the adherence index and the cellular morphology. Inflammatory macrophages were obtained from peritoneal washed of Wistar rats. The evaluation of the adherence capacity of these cells to the plastic surface was conducted in Eppendorf tubes containing RPMI, after treatment with the bleaching agents diluted in 1:10, 1:100 and 1:1000 for 15 and 30 min, and incubation at 37 degrees C and humidified atmosphere of 5% CO(2) in air. The cellular morphology was verified after incubation of the cells treated with the bleaching agents in culture plaques and compared with normal cells in culture medium. Results showed that sodium perborate neither increased the adherence index, nor altered the cellular morphology when compared to the control group. The distribution, cellular morphology, cytoplasmatic and nuclear characteristics, reproduced the aspects observed in normal macrophages. However, the treatment with 30% hydrogen peroxide presented an increase in adherence index when compared to the control group (RPMI), in all dilutions, according to Mann-Whitney test (n=08 and p=0.001 for dilutions 1:10 and 1:100, and n=08 and p=0.004 for dilution 1:1000). The morphology of the cells treated with this product presented structural alterations proportionally greater, depending on the dilution of this bleaching agent, and even in the highest dilution (1:1000) the cells presented very evident alterations. This irreversible cellular damage as well as the elevation of the adherence index, characterizes the aggressive potential of 30% hydrogen peroxide, regardless of its dilution. Sodium perborate, on the other hand, showed biocompatibitity, since, no morphological nor functional alteration was observed in macrophages.

MTA Obturation of Pulpless Teeth with Open Apices: Bacterial Leakage as Detected by Polymerase Chain Reaction Assay

Polymerase chain reaction (PCR) followed by reverse dot blot was used to detect Enterococcus faecalis leakage through mineral trioxide aggregate (MTA) apical obturations of pulpless teeth with open apices. Prepared root canals of 34 extracted teeth were given a standard apical foramen opening and received orthograde apical obturation with MTA; three groups had 1-, 2-, or 3-mm thickness. Sterilized specimens were inoculated with E. faecalis and incubated in sterile medium. DNA extracted from the specimens was amplified by polymerase chain reaction, which yielded a specific segment of E. faecalis 16S rDNA. On day 10 of incubation, no specimens were contaminated. On day 50, almost 17% of specimens were contaminated, with no statistically significant difference between groups (Chi-square = 0.48; df = 2; p = 0.787). Therefore, MTA provides an adequate seal even in cases of orthograde apical obturation of pulpless teeth with open apices.

Restoration of endodontically treated teeth: a review

The concept of restoring a pulpless tooth with post, core and/or crown is based on the belief that the root-filled tooth becomes brittle as a result of loss of moisture content. However, recent studies revealed that the moisture content of a root-filled tooth is not significantly different from that of a vital tooth. A survey of dentist' philosophies and techniques of restoring pulpless tooth conducted in the United States of America (U.S.A.) revealed that approximately 50 per cent of the respondents believed that a post would reinforce an endodontically treated tooth, while other studies reported no statistically significant advantage to reinforcing the teeth. Therefore, the concept that all anterior teeth that have received root canal therapy require posts and crowns is not supported by recent studies. But the access cavity for the root canal treatment should be as conservative as possible so that the tooth is not weakened unnecessarily. Based on a review of the literature, this article intends to provide a guideline for the restoration of endodontically treated teeth.

The Incidence of Bacteremia in Endodontic Manipulation: Preliminary Report

Endodontic procedures have been under criticism by certain members of the profession for a long time, particularly as related to focal infection. Many still believe that pulpless teeth, especially those with an area of rarefaction, are a focus of infection which ultimately could produce a focal infection. The elimination of this possible focus of infection by conservative endodontic methods has been and still is questioned. Exodontic procedures, on the other hand, have never been censored. It is believed that removal of the tooth eradicates the focus and thereby eliminates the complication of a metastatic or focal infection. We should like to offer evidence that proper endodontic procedures can produce less likelihood of focal infection than exodontic procedures. It has been demonstrated clinically and experimentally that focal infection can develop as a result of a bacteremia (1) following extraction of teeth. The incidence of bacteremia as a result of exodontic and periodontal manipulation has been reported by numerous investigators (2–7). In the extraction of teeth, it has been shown that heavy trauma invariably produces a greater dispersal of microorganisms into the blood stream from the original focus. Therefore, the reduction of trauma can curtail the number of bacteria that enter the blood stream and thus prevent the complication of the development of certain organic diseases, particularly the dread subacute bacterial endocarditis in patients who have a history of rheumatic heart disease. Investigations of the relationship of endodontic procedures to bacteremia are very meager. Robinson and his group (5) did not detect the presence of bacteria in the blood in seven cases following reaming procedures and filling of the root canals. They did not state how many of each were done and whether or not cultures were taken of the root canals to determine the presence of microorganisms. In all instances they used the rubber dam. While many laboratory procedures were discussed, specific procedures for this series of cases were not given. Beechen and his group (8) found no evidence of positive blood cultures in pulpotomy procedures in one permanent molar and twenty-two deciduous molars. Their patients ranged in age from 4 to 11 years. The coronal portion of the pulp was cultured, and the organisms were identified in each case. They were able to obtain a 10 ml. sample of blood in their young patients. Ross and Rogers (9) treated six cases and found that in three cases of vital extirpation blood cultures were all positive, while in three cases of necrosis of the pulp they were all negative. They explain that the positive blood cultures were due to the organisms being carried into the blood stream through the pulpal circulation by means of the broaches and reamers as they traversed the infected portion of the carious process in the coronal portion of the pulp. The three cases of necrosis of the pulp produced negative cultures because there was no pulpal circulation to propel the bacteria into the blood stream. They did not take cultures of the coronal portion or root canals of the teeth tested. The following study was done to determine whether or not endodontic procedures can produce a bacteremia. If no bacteremias or a smaller incidence of bacteremias occur following endodontic procedures as compared to exodontic procedures, endodontics may be the treatment of choice, particularly for patients with valvular heart disease.

The role of organic tissue on the punch shear strength of human dentin.

The tendency to fracture of human teeth has been attributed to numerous reasons, including pulpless tooth dehydration, tooth structure degeneration, and excessive spreader loading. To date, however, no consistent data has been gathered to ascertain the effect of organic tissue on the biomechanical properties of human dentin. This study explored the influences of organic tissue removal on the morphological changes and punch shear strength by means of low vacuum wet scanning electron microscope (Wet-SEM) and punch shear apparatus. The crown dentin slices with a thickness of 0.45-0.50 mm were prepared from extracted human molars. These specimens were immersed in 5% NaOCl for 1, 3, and 6 h to remove the organic tissue. The dynamic morphological changes of these dentin slices after immersion were observed using Wet-SEM. In addition, the punch shear strength and stiffness of specimens were measured. The removal of organic tissue by 5% sodium hypochlorite treatment caused many cracks on the specimen surfaces. Intertubular and peritubular dentin were also affected, causing an abnormal configuration of dentinal tubule orifices. The 5% sodium hypochlorite treatment for 1, 3, and 6 h significantly reduced the punch shear strength of dentin. As the immersion time increased, the values of punch shear strength also diminished. The organic tissue loss of human dentin would affect the structure of intertubular and peritubular dentin and cause many cracks on the dentin surface. The punch shear strength of human dentin also reduced after removal of organic tissue.

Effect of different filling materials in combination with intraradicular posts on the resistance to fracture of weakened roots.

The preservation and restoration of severely weakened pulpless teeth is a difficult and relatively unpredictable procedure. This study evaluated the resistance to fracture of experimentally weakened bovine roots internally reconstructed with different filling materials in combination with prefabricated post compared with restored roots that were relatively intact. The roots of 75 mandibular bovine incisors with similar bulks were selected. Of these, 60 were internally prepared to standardized dimensions, thereby simulating weakness. All roots were filled with different restorative materials. The specimens were submitted to the fracture resistance testing with the application of a tangential compressive loading at an angle of 135 degrees in relation to the long axes of the roots. Results indicated statistically significant differences in relation to the root conditions. Weakened roots were less resistant to fracture than were controls. The roots restored with the resin cement demonstrated the lowest fracture resistance values, but statistically significant differences were observed only when compared with those restored by the resin-modified glass-ionomer cement. Resin-modified glass-ionomer cement, polyacid-modified resin composite and resin composite behaved similarly without statistically significant differences among them. None of the materials evaluated were capable of achieving the fracture resistance recorded for unweakened controls.

The use and predictable placement of Mineral Trioxide Aggregate in one-visit apexification cases.

Endodontic treatment of the pulpless tooth with an immature root apex poses a special challenge for the clinician. The main difficulty encountered is the lack of an apical stop against which to compact an interim dressing of calcium hydroxide (Ca(OH)2), or the final obturation material. In these situations the unpredictability of the result, the difficulty in creating a leak-proof temporary restoration for the duration of treatment, and the difficulty in protecting the thin root from fracture may lead to complications when using traditional (Ca(OH)2-based) apexification techniques. Furthermore, given the increased mobility of today's society, lengthy treatment protocols are fraught with problems, and may not be followed through to completion. This may lead to ultimate failure of the case. Mineral Trioxide Aggregate (MTA) has recently been introduced for use in endodontics. Current literature supports its efficacy in a multitude of procedures including apexification. The focus of this paper is to propose a one-visit apexification protocol with MTA as an alternative to the traditional treatment practices with Ca(OH)2. One-visit apexification may shorten the treatment time between the patient's first appointment and the final restoration. The importance of this approach lies in the expedient cleaning and shaping of the root canal system, followed by its apical seal with a material that favours regeneration. Furthermore, the potential for fractures of immature teeth with thin roots is reduced, as a bonded core can be placed immediately within the root canal.