Effect of splinting times on the healing of intra-alveolar root fractures in 512 permanent teeth in humans: A Scandinavian multicenter study.

BACKGROUND/AIM: Long-term splinting of teeth with intra-alveolar root fractures has been considered important for the deposition of hard tissue between the root fragments. The aim of this study was to compare the healing outcomes in teeth with intra-alveolar root fractures relative to splinting times in three dental centers in Scandinavia, using historical data. MATERIALS AND METHODS: A total of 512 maxillary and mandibular incisors from three dental trauma centers were included in the study. Two of the centers used long-term splinting protocols of two to three months while the other center used a short-term splinting protocol of one month or less. Three outcomes were evaluated: (1) Healing with hard tissue (dentin and/or cementum). (2) Healing with connective tissue (periodontal ligament) interposition with or without bone between the fragments. (3) Non-healing due to the coronal pulp being necrotic and infected with granulation tissue interposed between the fragments. RESULTS: The mean splinting times were 18, 81, and 110 days in the three centers. Long-term splinting resulted in hard tissue healing more frequently than short-term splinting. Short-term splinting resulted in more connective tissue/bony healing than long-term splinting, while there was no difference in the frequency of non-healing between long-term and short-term splinting protocols. CONCLUSIONS: While the results suggest that long-term splinting favors hard tissue deposition, one cannot, however, conclude that long-term splinting definitely favors hard tissue healing since the treatment protocols were not randomized among the three centers. More clinical studies on the role of splinting time need to be done.

Jens Ove Andreasen, 1935-2020 Father of Dental Traumatology.

The life and professional contributions to dental traumatology of Dr. Jens Ove Andreasen are described in terms of his research, writing, teaching, and leadership.

Traumatically Intruded Permanent Teeth: Three Case Reports and a Review of Current Recommendations.

Intrusion of permanent teeth is not extensively covered in the literature compared to other injuries. Treatment guidelines have been published and clinical data is accumulating to support the current recommendations, which are illustrated in the three cases here. This review evaluates the current information about management of traumatically intruded permanent teeth. As more data accumulates, uncertainties with respect to both treatment recommendations and long-term outcomes can be expected to be elucidated.

Comprehensive management of a complex traumatic dental injury.

A 24-year-old female patient presented with complaint of palatal swelling and a sinus tract facial to tooth #22. She reported an injury to the tooth 15 years earlier and no recollection of treatment, although there was evidence of an endodontic access into the crown. Radiographically the root appeared to have stopped developing, and it was associated with a large periapical lesion. After 3 unsuccessful attempts at apexification using calcium hydroxide (CH), further examination including use of cone-beam computed tomography (CBCT) was carried out. The latter allowed for better evaluating the situation and for better planning a more comprehensive treatment plan to include surgical removal of the apical lesion. The large radiolucent area extended from tooth #21 to #23. Using a dedicated software tool developed to be used in conjunction with CBCT, volumetric assessment of the lesion was carried out for healing follow up. The root end was filled from the apical direction with newly developed accelerated silicate cement 4-5 mm into the apical part of the canal. Subsequently, the rest of the canal was filled with the same type of cement. At the 1-year postsurgical follow up, the tooth remained asymptomatic, and using the CBCT volumetric program, bony healing could be demonstrated.

The Effect of Calcium Hydroxide Pastes on Isolated Vital Nerve Fibers.

INTRODUCTION: Calcium hydroxide pastes (CHPs), commonly used for disinfecting root canals during endodontic treatment, are generally considered safe. However, accidental extrusions result in minimal injuries and little to no discomfort, except when extruded pastes come into contact with nerve bundles, such as the inferior alveolar nerve. Currently, there is a lack of information about the possible role of specific paste vehicles on the extent of nerve injury. The purpose of this study was to compare the role that paste vehicles, such as water or methylcellulose, may play when nerve fibers are exposed to CHP. METHODS: Isolated sciatic nerves of Sprague-Dawley rats were exposed to either water-based or methylcellulose-based CHP for varying durations of time (30, 60, or 90 minutes). Histopathological changes, including axonal edema, myelin alterations, and loss of cellular outlines, were assessed, and the degrees of changes were compared using chi-square intraclass correlation coefficient tests. RESULTS: Both groups exposed to the pastes demonstrated varying degrees of histopathologic changes, including axonal edema, myelin changes, and loss of cellular outlines, at different exposure times. The water-based calcium hydroxide paste induced these changes more rapidly than the methylcellulose-based paste. Similar patterns were observed in the scanning electron microscopic findings. Exposure time emerged as an important difference in the effects of the 2 pastes. In each of these tests, all observations of water-based paste exposure were rated as moderate to severe, whereas the observed cellular changes (axonal, myelin, and intact cellular outline) were rated as mild to moderate after exposure to methylcellulose-based paste for the same exposure durations. The chi-square tests indicated a statistically significant association between the material and each of the outcomes (axonal changes: χ²15 = 81.0, P < .001; myelin changes: χ²15 = 81.0, P < .001; intact cellular outline, χ²15 = 81.0, P < .001). The intraclass correlation coefficient value was 0.93. CONCLUSIONS: The study demonstrates that axonal and myelin damage increase with longer exposure times, with water-based CHP causing more damage than methylcellulose-based CHP at each time point.

Pulp regeneration after non-infected and infected necrosis, what type of tissue do we want? A review.

Regeneration (revitalization) of infected necrotic pulp tissue has been an important issue in endodontics for more than a decade. Based on a series of case reports, there appears to be evidence that new soft tissue can enter the root canal with a potential for subsequent hard tissue deposition resulting in a narrowing of the root canal. Very little is presently known about the exact nature of this tissue growing into the canal and how it may behave in the long term. In the case of regeneration of necrotic non-infected pulp tissue, a series of clinical and histological studies have shown that such events may take place in four variants: (i) Revascularization of the pulp with accelerated dentin formation leading to pulp canal obliteration. This event has a good long-term prognosis. (ii) Ingrowth of cementum and periodontal ligament (PDL). The long-term prognosis for this event is not known. (iii) Ingrowth of cementum, PDL, and bone. The long-term prognosis is only partly known, but cases developing an internal ankylosis have been described. (iv) Ingrowth of bone and bone marrow is a rare phenomenon and the long-term prognosis does not appear to be good. Based on current knowledge, expectations with respect to pulp regeneration (revitalization) of infected necrotic dental pulps are difficult to predict; more information than now available is needed before procedures for pulpal regeneration can be routinely recommended with a predictable long-term prognosis.

Will mineral trioxide aggregate replace calcium hydroxide in treating pulpal and periodontal healing complications subsequent to dental trauma? A review.

Mineral trioxide aggregate (MTA) has over the last two decades begun to take the place of calcium hydroxide (CH) in the treatment of a variety of pulpal and periodontal healing complications following dental trauma. These conditions include teeth with: (i) exposed pulps, (ii) immature roots and pulp necrosis, (iii) root fractures and pulp necrosis located in the coronal part of the pulps, and (iv) external infection-related (inflammatory) root resorption. The main reasons for replacing CH with MTA in these situations have generally been the delayed effect when using CH to induce hard tissues, the quality of such induced hard tissues, and finally the dentin weakening effect of CH, which in some instances lead to cervical root fractures in immature teeth. MTA appears, from a relatively few clinical studies, to overcome these shortcomings of CH. The lack of long-term clinical studies, however, may warrant a certain reservation in an unrestricted replacement of CH with MTA. A definite need for randomized clinical studies comparing CH and MTA in trauma healing situations is urgently needed.

Combined Root Canal Therapies in Multirooted Teeth with Pulpal Disease.

The types of pulpal disease found in multirooted teeth may vary from one root canal to the next. Current endodontic treatment strategies allow for options such as regenerative endodontics, vital pulp therapy, or conventional root canal treatment depending on the disease status of the pulp in a specific root canal. A combination of procedures was used in the 3 teeth in this case series based on the assumed pulpal status in each canal. The follow-up ranged from 24-27 months, and in each case the healing response was satisfactory. This report illustrates the use of a combination of treatment procedures that can provide specific treatment benefits in various clinical situations.

Reprint of: Jens Ove Andreasen, 1935-2020 Father of Dental Traumatology.

The life and professional contributions to dental traumatology of Dr Jens Ove Andreasen are described in terms of his research, writing, teaching, and leadership.

Factors Affecting the Removal Time of Separated Instruments.

INTRODUCTION: Separated endodontic instruments may adversely affect the outcome of endodontic treatment. The combination of ultrasonic techniques and dental operating microscopes appears to be effective in the removal of separated instruments compared with more randomized techniques. This study evaluated the roles of root canal curvature and separated instrument length on the time needed to loosen and retrieve the instrument fragments. METHODS: The retrieval procedures of 128 separated instruments referred to a private endodontic practice for retreatment by general practitioners were evaluated in patients who were monitored for a minimum of 6 months. Preoperative cone-beam computed tomographic images were used to measure separated instrument lengths in relation to the degrees of canal curvatures. Ultrasonic instruments were used in the initial phase to remove the tooth structure and to loosen the fractured instrument. In the second phase, ultrasonic instruments, wire loops, or XP Shapers (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) were used for fragment removal. The time periods for all procedures were recorded. Statistical analysis was completed applying log-normal regression, structural equation modeling, and linear regression using Stata Version 14.2 software (StataCorp LLC, College Station, TX). RESULTS: All separated instruments were successfully retrieved. Using the protocol in this study, 89.8% of the instruments were removed using ultrasonic instruments alone with a mean time of 221 seconds. The instrument removal time was dependent on both the instrument length and the root canal curvature. Additionally, preparation times were proportionately longer with increasing separated instrument lengths when the loop device was required. CONCLUSIONS: The preparation phase appears to have an important role in the retrieval of separated instruments. Preparation times for both non-loop and loop groups demonstrate that length and curvature are independent predictors of the log-transformed time. Generally, procedure times were extended with increasing file lengths and higher degrees of canal curvature.

Dens evaginatus: Current treatment options.

BACKGROUND: Teeth with dens evaginatus (DE) are more commonly observed in Western countries than previously. This is due to the increase in populations of patients of Asian origin, in whom DE is more common than in people of European origin. The interest in DE has also increased with the introduction of a procedure called regenerative endodontics. CASE DESCRIPTION: A narrative review of treatment options for teeth with DE is presented, based on pulpal conditions and maturity of the teeth. PRACTICAL IMPLICATIONS: Early recognition of teeth with DE allows for treatment choices that generally lead to good outcomes and can aid in preserving developing teeth in young patients.

Treatment options for permanent teeth with coronal one-third root fractures.

BACKGROUND AND OVERVIEW: Teeth with coronal one-third root fractures are considered to have a poor prognosis. Historically, such teeth were likely to be extracted. Observations have indicated that at least some teeth with such fractures can survive for a significant amount of time. CASE DESCRIPTIONS: The authors report on 2 cases of coronal one-third root fractures that have survived for 10 and 35 years and suggest that the long-term splinting of these teeth aided in their survival. CONCLUSION AND PRACTICAL IMPLICATION: Stabilizing teeth with coronal one-third root fractures may allow such teeth to survive for long periods, which can be of great benefit, especially for young patients.

Direct pulp capping with mineral trioxide aggregate: an observational study.

BACKGROUND: Pulp capping in carious teeth has been considered unpredictable and therefore contraindicated. A recently developed material, mineral trioxide aggregate (MTA), resists bacterial leakage and may provide protection for the pulp, allowing repair and continued pulp vitality in teeth when used in combination with a sealed restoration. METHODS: Forty patients aged 7 to 45 years accepted pulp-capping treatment when they received a diagnosis no more severe than reversible pulpitis after undergoing cold testing and radiographic examination. The primary author removed caries using a caries detector dye and sodium hypochlorite solution for hemostasis and placed MTA over the exposures and all surrounding dentin. The operator then restored the teeth provisionally with unbonded Clearfil Photocore (Kuraray Medical, Okayama, Japan). During a second visit, the operator restored the teeth with bonded composite after sensibility testing and confirmed MTA curing. At recall appointments, patients were evaluated for reparative dentin formation, pulpal calcification, continued normal root development and evidence of pathosis. RESULTS: Over an observation period of nine years, the authors followed 49 of 53 teeth and found that 97.96 percent had favorable outcomes on the basis of radiographic appearance, subjective symptoms and cold testing. All teeth in younger patients (15/15) that initially had open apexes showed completed root formation (apexogenesis). CONCLUSIONS: MTA can be a reliable pulp-capping material on direct carious exposures in permanent teeth when a two-visit treatment protocol is observed. PRACTICE IMPLICATIONS: Vital pulp therapy using MTA is a treatment option for teeth diagnosed with a condition no more severe than reversible pulpitis.

Measurement of adhesion of endodontic sealers to dentin.

The bond strength of root canal sealers to dentin seems to be an important property for maintaining the integrity of the seal of root-canal fillings. In the few studies published, various assessment methods were used so quantitative comparison is not possible. The purpose of this study was to develop an effective and easily reproducible model and to test it with nine contemporary, commercially available endodontic sealers. After slicing off the coronal 2 mm of extracted third molars, the exposed dentin served as test surfaces. The teeth were fixed with plaster in 1-inch phenolic rings. Five-mm long sections of polyethylene tubing, filled with freshly mixed sealer, were placed on the dentin and tested for shearing bond strength after setting. A custom-made holder allowed the rings to be attached to an Instron machine, activated at a cross-arm speed of 0.5 mm/min. The mean bond strength, ranged from 0 to 4.9 MPa. The sealers were ranked and those that did not differ statistically in their bond strength were grouped together. This model provides a simple and reproducible means for measuring the in vitro bond strength of endodontic sealers.

Shearing bond strength of endodontic sealers to gutta-percha.

Strength of the bond of root canal sealers to gutta-percha seems to be an important property for maintaining the integrity of the apical seal. In the few studies published, different models and assessment methods were used. The purpose of our study was to adapt an effective and easily reproducible model and to test it on nine contemporary commercially available endodontic sealers. Gutta-percha disks with a diameter of 10 mm and thickness of 2 mm were prepared by warming gutta-percha cones and then fixed with plaster in 1-inch phenolic rings. Five-millimeter long sections of polyethylene tubing, filled with freshly mixed sealer, were placed on the gutta-percha and tested for shearing bond strength after setting. A custom-made holder was attached to the rings and placed in an Instron machine, which was activated at a cross-arm speed of 0.5 mm per minute. The bond strength ranged from 0 MPa to 6.4 MPa. The sealers were ranked, and those that did not differ statistically in their bond strength were grouped together. This model provides a simple and reproducible means for measuring the in vitro bond strength of endodontic sealers.

The effect of various concentrations of sodium hypochlorite on the ability of MTAD to remove the smear layer.

Various organic acids, ultrasonic instruments, and lasers have been used to remove the smear layer from the surface of instrumented root canals. The purpose of this study was to investigate the effect of various concentrations of sodium hypochlorite (NaOCl) as an intracanal irrigant before the use of MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) as a final rise to remove the smear layer. Ten operators, using a combination of passive step-back and rotary 0.04 taper, nickel-titanium files, prepared 80 single- and multirooted human teeth. Distilled water, four different concentrations of NaOCl, or MTAD was used as intracanal irrigant. The canals were then treated for 2 min with 5 ml of one of the following solutions as a final rinse: 5.25% NaOCl, sterile distilled water, 17% EDTA, or MTAD. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portion of each canal were examined under a scanning electron microscope. The results show that although MTAD removes most of the smear layer when used as an intracanal irrigant, some remnants of the organic component of the smear layer remain scattered on the surface of the root canal walls. The effectiveness of MTAD to completely remove the smear layer is enhanced when low concentrations of NaOCl are used as an intracanal irrigant before the use of MTAD as a final rinse. This regimen does not seem to significantly change the structure of the dentinal tubules.

Clinical implications of the smear layer in endodontics: a review.

It has been recognized for many years that root canal instrumentation produces a smear layer that covers the surfaces of prepared canal walls. This layer contains inorganic and organic substances such as fragments of odontoblastic processes and necrotic debris. There is a lack of agreement regarding the effect of the smear layer on the quality of instrumentation and obturation, but the smear layer itself may be infected and may protect the bacteria within the dentinal tubules. Various methods have been used to remove the smear layer. Conflicting results have been obtained from numerous in vitro studies regarding the significance of the presence or the removal of the smear layer.

Dental trauma guidelines.

Guidelines have been developed for management of numerous medical and dental conditions. If carefully developed and based on best available evidence, they serve a very useful purpose in giving information in dealing with health problems to health care providers as well as patients. The history of trauma guidelines is quite limited, but the American Association of Endodontists has been involved since the 1980s. In recent years, the International Association of Dental Traumatology has developed guidelines for management of traumatic dental injuries, with input from specialists in all relevant disciplines of dentistry. These guidelines, first developed and published in 2001 and updated twice since then, have been accepted as reliable recommendations for the urgent care of traumatic dental injuries; the most recent trauma guidelines were completed by the International Association of Dental Traumatology and published in 2012. The application of these guidelines is to provide both patients and practitioners with the best available information about management of such injuries. As with most guidelines, there are limitations that are primarily related to the level of evidence available, which is low. However, they are useful and, when followed, can lead to better outcomes than when no guidelines are used.

Dental trauma guidelines.

Guidelines have been developed for management of numerous medical and dental conditions. If carefully developed and based on best available evidence, they serve a very useful purpose in giving information in dealing with health problems to health care providers as well as patients. The history of trauma guidelines is quite limited, but the American Association of Endodontists has been involved since the 1980s. In recent years, the International Association of Dental Traumatology has developed guidelines for management of traumatic dental injuries, with input from specialists in all relevant disciplines of dentistry. These guidelines, first developed and published in 2001 and updated twice since then, have been accepted as reliable recommendations for the urgent care of traumatic dental injuries; the most recent trauma guidelines were completed by the International Association of Dental Traumatology and published in 2012. The application of these guidelines is to provide both patients and practitioners with the best available information about management of such injuries. As with most guidelines, there are limitations that are primarily related to the level of evidence available, which is low. However, they are useful and, when followed, can lead to better outcomes than when no guidelines are used.