Recovering the function and esthetics of fractured teeth using several restorative cosmetic approaches. Three clinical cases

Abstract – The teeth most commonly affected by trauma are the maxillary central incisors. The most frequent types of traumatic dental injuries to permanent teeth are enamel fractures, enamel and dentine fractures, and enamel and dentine fractures with pulp involvement. This article describes three clinical cases with different levels of traumatized maxillary incisors and several cosmetic approaches for recovery of the esthetics and the masticatory function, as well as the social/psychological aspects of treatment. All cases involved young adult men. The three clinical cases involve dentin and enamel fractures, dentin and enamel fractures with pulp exposure, and dentin and enamel fractures with pulp exposure associated with root fracture. The cosmetic treatments used to resolve fractures were direct composite resin by layering technique, indirect all‐ceramic restorations (laminate veneer and ceramic crowns over the teeth), and immediate implant after extraction followed by immediate loading (ceramic abutments with ceramic crown over implant). In all three cases, excellent functional and esthetic results were achieved by use of these treatment modalities. The patients were very satisfied with the results.     

Follow-up study of permanent incisors with enamel fractures as a result of an acute trauma

Abstract – The present investigation evaluated the prognosis for vitality after and acute trauma in 2891 permanent incisors with enamel fracture as the only damage, and in 476 incisors with enamel fracture combined with other symptoms on the damaged tooth. Pulpalnecrosis developed in 57 teeth (1.7%). Acute treatment in connection with enamel fracture was only performed in half of the cases and had no importance on vitality. The combination of enamel fracture and concussion or mobility resulted in pulpal necrosis in 8.5% of cases, and cases involving both mobility and concussion meant pulpal necrosis in 14% of teeth. The findings clearly illustrated that an enamenamel fractures is an injury with an extremely favorable prognosis, and that the risk group can be narrowed to cases of combined injuries involving the supportive tissue.     

Outcomes for root-fractured permanent incisors: a retrospective study

PURPOSE: The objective of this study was to assess the outcomes for treated root-fractured permanent incisors with respect to pulp vitality, root tissue union, and tooth survival and to examine the effects of clinical and radiographic parameters and rigid splinting on the outcome. METHODS: Eighty-four teeth were identified and data extracted from case notes prior to transfer to an SPSS data base for analysis. The odds ratios for each factor were calculated and the significance of differences was determined. Tooth loss and relevant risk variables were examined using Cox's regression model and Kaplan-Meyer survival curves. RESULTS: Fourteen (17%) had fractures in the apical third, 47 (56%) in the middle third, and 23 (27%) in the coronal (gingival) third. Twenty-four (29%) also had crown fractures involving enamel and dentine. Crown fractures were identified as significant risk factors for pulp vitality. Loss of pulp vitality, horizontal displacement, and extrusive displacement of the coronal fragment were significant risk factors for hard root tissue union. Survival was poorest with gingival third fractures with 14 (61%) of these teeth being lost. Splinting rigidly had no significant effect on pulp vitality and type of root tissue healing. CONCLUSIONS: Loss of pulp vitality was significantly associated with enamel-dentine crown fracture. Hard root tissue union was significantly affected by pulp necrosis and luxation of the coronal fragment. Survival was poorest for root fractures within the gingival third of the root. Splinting with rigid fixation had no significant effect on pulp vitality and type of root tissue union.     

Effect of simulated pulpal microcirculation on intrapulpal temperature changes following application of heat on tooth surfaces

Aim  To evaluate ex vivo whether a simulated pulpal microcirculation inside a pulp chamber influenced intrapulpal temperature rise following application of heat on tooth surfaces.
Methodology  An ex vivo model that allowed the circulation of 37 °C warm water inside the pulp chamber of an extracted human tooth was designed. The experimental model resembled pulpal microcirculation. After application of specific thermal stimuli for 30 s to the external surface of 15 maxillary central incisors, lateral incisors and canines, temperature changes were measured in the pulp chamber. The Greenhouse–Geisser and Bonferroni tests were used for analysis of the data. The level of significance was set at 0.05.
Results  Significant differences were found in all three groups of teeth between temperature measurements with or without intrapulpal water flow. Additionally, temperature changes resulting from the application of different stimuli to the group of lateral incisors were significantly greater compared with the other groups of teeth ( P  < 0.05).
Conclusions  The importance of the cooling effect of simulated pulp microcirculation in the thermal behaviour of the dentine was established. Thickness of tooth tissue influenced significantly pulp temperature rise ex vivo .     

Bonding of enamel-dentin crown fractures with GLUMA® and resin

Abstract A procedure is described whereby enamel-dentin fragments can be bonded to the remaining tooth substance. The tooth and tooth fragment are conditioned with EDTA and GLUMA® and then bonded together with a light-cured composite resin. Results based on the restoration of 76 complicated and uncomplicated crown fractures of permanent incisors with up to 2 years' observation indicate that teeth bonded with GLUMA® can withstand normal chewing forces. Long-term studies on the retention of bonded fragments, color stability and pulpal reaction to bonding are now in progress.     

A retrospective evaluation of patients with uncomplicated crown fractures and luxation injuries

Abstract— This paper is a review of the clinical findings from my thesis "Pulp survival and hard tissue formation subsequent to dental trauma". Traumatic injuries in children and adolescents are a common problem, and the prevalence of such injuries has increased over the last 10–20 years. The purpose of the present investigations was to evaluate the long-term results following uncomplicated crown fractures and luxations involving subsequent pulp canal obliteration. A total of 241 patients with 545 injured teeth were available for clinical examination, of whom 102 answered a questionnaire and were interviewed before oral examination. In addition, 82 permanent incisors presenting with pulp canal obliteration were followed for a period of 7 to 22 years (mean 16 years). The findings showed little pulpal response to crown fracture and subsequent restorative procedures as long as there was no concomitant periodontal injury (15-year follow-up). Approximately every fourth resin composite filling was rated as unacceptable at clinical examination. The interview showed that half of the individuals were dissatisfied with the color and/or anatomic form of the composite restoration. Pulp canal obliteration was found in all luxation categories, and 69% of the teeth demonstrated yellow crown discoloration. According to the survival curve the 20-year pulp survival rate diagnosed radiographically was 84%. Although the risk of pulp necrosis increased with time, routine endodontic intervention of teeth with ongoing pulp canal obliteration of the root canal did not seem justified.     

Effect of luxation injuries on permanent teeth

Abstract Trauma to the supporting tissues of the teeth are among the most common dental injuries, leading to such complications as pulp canal obliteration, necrosis and root resorption. The aim of this investigation was to study the outcome for young permanent teeth subjected to luxation injuries. From 108 dental records 171 teeth with injuries to the supporting tissue were selected. The material comprised 130 subluxated, 15 extruded, 9 intruded, 15 exarticulated and 6 laterally luxated teeth in children aged 6–19 years. Apart from luxation, 59 teeth (35%) had additional crown and root fractures. 65% of the teeth recovered without complications. 78% of the subluxated teeth and 24% of the luxated teeth showed uneventful posttraumatic healing. Concomitant uncomplicated crown fractures or root fractures without displacement of the coronal fragment did not interfere with the healing. Of 60 teeth with healing complications, 52 (87%) were subsequently recorded as healed, the remaining 8 were extracted or had progressive root resorption. Loss of pulp vitality and external root resorptions were the most often recorded complications (28% and 17% of the total material respectively). Pulp canal obliteration was noted in 3% of the cases. Extent of injury and degree of tooth maturity were found to be related to healing compliations.     

Fracture strength of intact and fragment-bonded teeth at various velocities of the applied force

Bonding of a tooth fragment to the remaining tooth substance can restore crown fracture of an anterior tooth. In this study, sheep central incisors were used. The crowns were fractured transversely and the crown fragment was bonded to the remaining tooth structure. This technique involves acid etching, use of an experimental adhesive (Gluma+) and a BisGMA/TEGDMA resin. The mean fracture strength of the restored teeth was not significantly different from that of intact teeth when tested at a rather low crosshead speed (0.5 mm/min) but different and about 30% lower when tested at a higher crosshead speed (500 mm/min). In studies aiming to test resistance to forces which might cause trauma, it might be appropriate to use a high crosshead speed.     

牙齿折断性损伤分类和治疗原则

牙齿折断性损伤分为：冠折、根折和冠根折。冠折时建议采用断冠粘接,较年轻恒牙建议应用盖髓术或部分牙髓切断术以保持牙髓活性;根折时,建议尽早复位;冠根折时建议采取急诊处置,临时粘接断冠。在根中1/3根折、根颈1/3根折和冠根折时,序列治疗有助于保存断冠。     

Evaluation of tooth‐fragment reattachment: a clinical and laboratory study

Abstract – Purpose: To evaluate the restoration of fractured teeth by reattaching tooth fragment to its tooth remnant in a group of children and adolescents, and to compare the results with those of a laboratory study. Materials and Methods: The clinical study was conducted on 43 fractured incisors: 22 uncomplicated crown fractures (Group A) and 21 complicated crown fractures (Group B). The 43 incisal fragments: 23 were kept dry for 47 h and 20 were kept wet for 24 h by the patients before they were reattached. The fragments were kept in 0.9% saline solution for 30 min before reattachment. The fragments in Group A were reattached using a dentin bonding agent, a flowable and a hybrid resin composite, whereas the fragments in Group B were reattached to the tooth remnant after a pulpotomy was performed. The laboratory study was conducted on 56 extracted incisors. Teeth were divided equally into four groups: Group I – Uncomplicated crown fracture + wet medium; Group II – Uncomplicated crown fracture + dry medium; Group III – Complicated crown fracture + wet medium, and Group IV – Complicated crown fracture + dry medium. The fragments were then reattached in a manner that was similar to that used in the clinical study. The restored teeth were then re‐fractured. All data were analyzed statistically. Results:  In the clinical study, the restored teeth were followed up for 2 years. Neither the type of trauma nor the storage medium had any significant effect on the survival, color, and bond strength of the restored teeth when assessed in the clinical and laboratory study. The color disharmony that was encountered initially in restored teeth resolved significantly on its own accord within 12 months after reattachment of the fragment. Conclusion:  Fragment reattachment can be used to treat fractured teeth successfully in children and adolescents.     

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??Teeth fractures include crown fracture?? root fracture and crown-root fracture. If the tooth fragment is available?? it can be bonded to the tooth. In young patients with immature?? still developing teeth?? it is advantageous to preserve pulp vitality by pulp capping or partial pulpotomy. Also?? this treatment is the choice in young patients with completely formed teeth. If displaced?? reposition the coronal segment of the tooth as soon as possible. As an emergency treatment a temporary stabilization of the loose segment to adjacent teeth can be performed. Sequential therapy for traumatized teeth with mid-root fracture or cervical third fracture or crown-root fracture could preserve the coronal fragment.     

Laser light passage through restored and carious posterior teeth

Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty‐two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio‐bucco‐lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one‐third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF.     

The effect of normal occlusal forces on fluid movement through human dentine in vitro

Receptors inside human incisors appear to respond to stress (comparable to pressure as opposed to force) on the crown. This ability may be used to limit the stress applied to teeth or to discriminate between the hardness of objects clenched between upper and lower teeth. Here the hypothesis that these receptors are activated by fluid squeezed out of dentinal tubules when the loaded tooth is stressed was tested. Vertically compressing the crowns of extracted human teeth with loads of from 20 to 120 N, similar to those used in other studies and during natural chewing, did indeed displace fluid into the pulp. The fluid was displaced away from the crown immediately after the tooth had been loaded and moved back into the crown when the load was removed. The volume ranged from 3.5 to 22.2×10³ pl, similar to that known to stimulate single pulpal nerve fibres. Thus, normal chewing forces could displace sufficient fluid out of dentine to excite putative mechanoreceptors somewhere inside the dentine/pulp complex.     

Thermal stimulation causes tooth deformation: a possible alternative to the hydrodynamic theory?

OBJECTIVES: To investigate the relationship between temperature distribution and tooth structure deformation during and after localised application of thermal stimuli used during pulp vitality testing. METHODS: Strains and temperature changes within tooth structures were recorded when three different thermal stimuli, namely heated gutta percha (120-140 degrees C), carbon dioxide dry ice (-72 degrees C) and refrigerant spray (-50 degrees C), were applied to extracted bovine incisors. Each stimulus was applied for 5s on the labial enamel surface in a random order, with a 30-min interval between tests. Finite element analysis was performed on basic geometrical shapes to investigate structural deformation in relation to temperature change. RESULTS: Application of thermal stimuli to the labial enamel surface resulted in rapid development of strain at the pulpal dentine surface before any temperature change was detected at the dentino-enamel junction. The strain pattern was biphasic; heat produced an initial contraction of the pulpal surface, followed by an expansion, and the reverse pattern was found with cold stimulation. Finite element analysis confirmed that the initially pronounced thermal gradient across the enamel and dentine caused rapid flexural deformation before temperature changes reached the dentino-enamel junction. When the temperature changes reached the pulpal dentine and thus reduced the thermal gradient, the direction of the strain was reversed. CONCLUSION: These results indicate possible alternatives to the hydrodynamic theory for thermal stimuli applied to intact teeth. Mechanically induced dentine deformation may trigger nerve impulses directly, or may exert mechanically induced dentinal fluid flow that triggers nerve activity.     

Bonding of enamel-dentin crown fragments after crown fracture. An experimental study using bonding agents

Abstract Previous experimental studies into the use of dentin bonding agents for reattachment of enamel-dentin crown fragments have demonstrated fracture strength about 50–60% of that of intact teeth. In the clinic this has been reflected in the frequent need of repeated bonding of the treated incisors due to refracture. Recently newer bonding agents have been developed which can bond equally well with enamel and dentin. Employing the same experimental model, these bonding agents (All-Bond 2, Scotchbond MP) were used to reattach crown fragments to the remaining portion of sheep incisors. Loading of teeth bonded with these agents in an Instron testing machine at a speed of 1 mm/min demonstrated similar fracture strengths as those previously achieved with Gluma, Scotchbond 2 or Tenure. A second study was carried out whereby fragments were bonded with Scotchbond MP and loaded at various speeds. The results demonstrated that the fracture strength decreased exponentially with increased loading speed. By extrapolation, it was concluded that the strength was nil at a loading speed of approximately 2 m/min. It was concluded that the weak link in the bond between tooth fragment and remaining tooth structure is the bonding resin. Theoretically, a resin which is slightly elastic might act as a shock absorber to withstand functional stress. However, studies carried out with resins of varying moduli of elasticity gave disappointing results probably due to their low flexural strength. It is concluded on basis of previous and present results that reattachment with a bonding resin of the enamel dentin crown fragment after crown fracture is a realistic alternative to composite resin build-up although only half the strength of intact teeth is achieved.     

Long-term prognosis of crown-fractured permanent incisors. The effect of stage of root development and associated luxation injury

Objectives. The aim of the present study was to investigate pulp healing responses following crown fracture with and without pulp exposure as well as with and without associated luxation injury and in relation to stage of root development. Patient material and methods. The long‐term prognosis was examined for 455 permanent teeth with crown fractures, 352 (246 with associated luxation injury) without pulpal involvement and 103 (69 with associated luxation injury) with pulp exposures. Initial treatment for all patients was provided by on‐call oral surgeons at the emergency service, University Hospital (Rigshospitalet), Copenhagen. In fractures without pulpal involvement, dentin was covered by a hard‐setting calcium hydroxide cement (Dycal®), marginal enamel acid‐etched (phosphoric acid gel), then covered with a temporary crown and bridge material. In the case of pulp exposure, pulp capping or partial pulpotomy was performed. Thereafter treatment was identical to the first group. Patients were then referred to their own dentist for resin composite restoration. Results. Patients were monitored for normal pulp healing or healing complications for up to 17 years after injury (x = 2·3 years, range 0·2–17·0 years, SD + 2·7). Pulp healing was registered and classified into pulp survival with no radiographic change (PS), pulp canal obliteration (PCO) and pulp necrosis (PN). Healing was related to the following clinical factors: stage of root development at the time of injury, associated damage to the periodontium at time of injury (luxation) and time interval from injury until initial treatment. Crown fractures with or without pulp exposure and no concomitant luxation injury showed PS in 99%, PCO in 1% and PN in 0%. Crown fractures with concomitant luxation showed PS in 70%, PCO in 5% and PN in 25%. An associated damage to the periodontal ligament significantly increased the likelihood of pulp necrosis from 0% to 28% (P < 0·001) in teeth with only enamel and dentin exposure and from 0% to 14% (P < 0·001) in teeth with pulp exposure. Conclusions. In the case of concomitant luxation injuries, the stage of root development played an important role in the risk of pulp necrosis after crown fracture. However, the primary factor related to pulp healing events after crown fracture appears to be compromised pulp circulation due to concomitant luxation injuries.     

Dens invaginatus:aetiology, classification, prevalence, diagnosis, and treatment considerations

Dens invaginatus is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. Affected teeth show a deep infolding of enamel and dentine starting from the foramen coecum or even the tip of the cusps, and which may extend deep into the root. Teeth most affected are maxillary lateral incisors and bilateral occurrence is not uncommon. The malformation shows a broad spectrum of morphologic variations and frequently results in early pulp necrosis. Root canal therapy may present severe problems because of the complex anatomy of the teeth. Aetiology, prevalence, classification, and therapeutic considerations including root canal therapy, apical surgery and prevention of pulpal involvement are reviewed.     

Treatment of crown fractures with pulp exposure in primary incisors

The treatment options of enamel dentin crown fractures with pulpal exposure in the primary dentition traditionally consist of direct pulp capping, pulpotomy, pulpectomy, or extraction. Many clinicians disagree on the most appropriate treatment, and individual preferences exist within dentistry. Partial pulpotomy, also known as the Cvek pulpotomy, is a mode of treatment which is widely used in the permanent dentition but less so in primary teeth. This conservative technique is described and its advantages over the others are presented. In addition, a report of a case with a 2-year follow-up is also included. The purposes of this article are: (1) to present the indications and contraindications of the various treatment modalities for primary incisors with complicated crown fractures; and (2) to suggest partial pulpotomy as a conservative and more appropriate approach for primary incisors with complicated crown fracture.     

Combination injuries 2. The risk of pulp necrosis in permanent teeth with subluxation injuries and concomitant crown fractures

Abstract – Background: The reported risk of pulp necrosis (PN) is generally low in teeth with subluxation injuries. A concomitant crown fracture may increase the risk of PN in such teeth. Aim: To analyse the influence of a concomitant trauma‐related infraction, enamel‐, enamel–dentin‐ or enamel–dentin–pulp fracture on the risk of PN in permanent teeth with subluxation injury. Material and Methods: The study included 404 permanent incisors with subluxation injury from 289 patients (188 male, 101 female). Of these teeth, 137 had also suffered a concomitant crown fracture. All the teeth were examined and treated according to a standardized protocol. Statistical Analysis: The risk of PN was analysed separately for teeth with immature and mature root development by the Kaplan–Meier method, the log‐rank test and Cox regression analysis. The level of significance was set at 5%. Risk factors included in the analysis were gender, patient age, crown fracture type, mobility and response to an electric pulp test (EPT) at the initial examination. Results: Teeth with immature root development: The risk of PN was increased in teeth with a concomitant enamel fracture (log‐rank test: P = 0.002), enamel–dentin fracture (log‐rank test: P < 0.0001), enamel–dentin–pulp fracture (log‐rank test: P < 0.0001) and in teeth with no response to EPT at the initial examination [hazard ratio: 21 (95% confidence interval, CI: 2.5–172.5), P = 0.005]. Teeth with mature root development: the risk of PN was increased in teeth with an enamel–dentin fracture [hazard ratio: 12.2 (95% CI: 5.0–29.8), P < 0.0001], infraction [hazard ratio: 5.1 (95% CI: 1.2–21.4) P = 0.04] and in teeth with no response to EPT at the initial examination [hazard ratio: 8 (95% CI: 3.3–19.5), P < 0.0001]. Conclusion: A concomitant crown fracture and no response to EPT at the initial examination may be used to identify teeth at increased risk of PN following subluxation injury.     

The induction of reparative dentine by enamel proteins

AIM: This study was designed to examine whether enamel matrix derivative (EMD) could induce reparative dentine formation without eliciting adverse side-effects in pulpotomized teeth in the miniature swine. METHODOLOGY: Pulpotomy was performed in 36 mandibular incisor teeth from 11 adult miniature swine. Following the surgical procedure, the exposed pulp tissue was treated with EMD or covered with a calcium hydroxide preparation (Dycal). Following an observation period of 3, 4 and 8 weeks, the experimental teeth were extracted and examined using light microscopy and histometric analysis. The total amount of reparative dentine formed in the EMD-treated teeth was calculated as total area using digital histomorphometry analysis of the five central-most sections from each experimental tooth. RESULTS: In the EMD-treated teeth, substantial amounts of dentine-like tissue formation consistently led to a complete hard-tissue bridging of the defects. The onset of hard tissue formation could be observed after 2 weeks and was located only on the pulpal wound. More limited dentine formation was also observed in Dycal-treated teeth. However, in these teeth the new hard tissue formed at the expense of pulp chamber width, causing narrowing of root canals. The total amount of reparative dentine formed in the EMD-treated teeth was significantly higher (P<0.005) than in the Dycal-treated specimens. CONCLUSION: These results demonstrate the potential of EMD as a biologically active pulp-dressing agent that specifically induces pulpal wound healing and dentine formation in the pulpotomized teeth without affecting the normal function of the remaining pulp.