415颗未露髓冠折牙预后的回顾性研究

目的分析未露髓冠折牙的预后及影响预后的相关因素。方法对2000-2006年于北京大学口腔医院儿童口腔科注册的系统病历中,观察期大于等于6个月的未露髓恒牙冠折病历进行回顾性研究,记录患者的性别、年龄、外伤类型、是否伴有牙周组织损伤、外伤牙位、牙根发育情况、外伤后就诊时间、是否接受急诊处理以及牙髓组织预后等内容。应用Logistic回归分析与简单冠折和冠折伴牙周组织损伤牙髓组织预后相关的因素。结果符合纳入标准的病历307份,涉及外伤牙415颗。冠折伴牙周组织损伤牙齿的牙髓坏死率为34.0%,简单冠折牙齿的牙髓坏死率为22.7%,二者间的差异具有统计学意义（P<0.05）。患者年龄和外伤类型与简单冠折牙髓组织预后具有显著相关性,牙根发育和外伤类型与冠折伴牙周组织损伤牙髓组织预后具有显著相关性。结论是否伴有牙周组织损伤与冠折牙齿的预后具有显著相关性。     

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.     

年轻恒牙脱出性损伤后牙髓预后及相关因素分析

目的 评估年轻恒牙脱出性损伤后牙髓组织的预后,分析可能影响预后的相关因素.方法 对2000年1月至2006年12月于北京大学口腔医学院·口腔医院儿童口腔科就诊且资料完整、观察期≥6个月的157例(238颗牙)年轻恒牙外伤病历进行回顾性研究,记录患者性别及年龄、外伤类型、外伤牙位、牙根发育情况、外伤后就诊时间、是否接受急诊处理以及牙髓组织预后类型.应用Logistic回归模型分析与牙髓预后相关的因素.结果 符合纳入标准的外伤病历共157份,外伤牙238颗,其中38颗(16.0%)出现牙髓坏死,5颗(2.1%)出现髓腔钙化,牙髓存活195颗(81.9%).挫入移位牙髓坏死发生率最高(66.7%).牙根发育情况和外伤类型与牙髓组织预后具有显著相关性(P<0.05).结论 牙齿脱出性损伤中,挫人移位最易发生牙髓坏死.牙根发育情况和外伤类型与脱出性损伤牙齿的牙髓预后具有相关性.     

Pulpal healing after luxation injuries and root fracture in the permanent dentition

Abstract Pulpal healing patterns were studied in a clinical material of 637 luxated and 95 root-fractured permanent incisors followed routinely for up to 11 years. It was found that pulpal healing patterns could generally be divided into 3 groups according to the degree of injury sustained by the pulp: little, moderate or severe. Thus after luxation injuries, pulp survival could be without radiographic change (PS), with pulp canal obliteration (PCO) or nonhealing (pulp necrosis (PN)). After root fracture, similar healing patterns could be observed: healing by hard tissue union of fragments (HT), by connective tissue union of fragments (CT) or by nonunion due to interposition of granulation tissue between fragments (GT) resulting from PN of the coronal fragment. In both trauma situations, healing or nonhealing could be determined by type of luxation injury, stage of root development and type of fixation used (forceful application of orthodontic bands vs. passively applied acid-etch fixation). Pulpal healing complications (PN or GT) were based on clinical findings (coronal discoloration, loss of pulpal sensibility) and radiographic findings (resorption processes of the lamina dura at the root apex or at the level of the root fracture). However, in both injury groups the same changes could also be seen to be intermediate steps in the pulpal healing process. Based on findings from these studies, hypotheses for the mechanics of pulpal healing are proposed as well as guidelines for acute and later treatment of dental luxations, root fractures and the diagnosis of healing complications.     

Relationship between pulp dimensions and development of pulp necrosis after luxation injuries in the permanent dentition

Abstract A relationship between type of luxation injury, stage of root development and development of pulp necrosis after injury has been demonstrated. It was therefore decided to delve more deeply into the relationship between stage of root development and the later development of pulp necrosis after injury in a material of luxated permanent teeth. In this context, the diameter of the apical foramen and the distance from the apical foramen to the pulp horn, as measured on radiographs taken at the time of injury, were used as indicators of root development. In order to justify this approach, the precision of the measuring technique and the accuracy of the radiographic technique were studied. Regarding precision of the measuring technique, it was found that there was a 1% to 4.3% error of the means of all measurements for the various parameters and exposure techniques employed. With respect to accuracy of the radiographic technique, it was found that there was a systematic error in the radio-graphic technique which resulted in a median relative distortion of between 3.5% and 8% image magnification for the various parameters and the exposure techniques employed. These findings indicated that the measuring technique employed in the present investigation was reliable for studying the parameters in question. In a material of 226 extruded, intruded and laterally luxated maxillary permanent incisors, observed for up to 10 years, it was found that the development of pulp necrosis after injury was significantly related to the diameter of the apical foramen. For extruded and laterally luxated teeth, the smaller the diameter, the greater the probability of pulp necrosis. Intruded teeth with incomplete root development (i.e. radiographic diameters ≥1.2 mm) were associated with a much higher probability of pulp survival than teeth with complete root development (i.e. radiographic diameters ≤0.7 mm). The distance from the apical foramen to the pulp horn did not appear to be of importance in predicting pulp survival when diameter of the apical foramen was taken into account. Pulp survival after luxation injuries with displacement thus appears to be dependent upon the size of apical contact between the pulp and the periodontium.     

年轻恒牙震荡和移位后牙髓与牙根变化的临床研究

年轻恒牙外伤后,牙髓坏死和牙根吸收在牙齿震荡和牙齿移位中的发生率及发生的时间;牙根的表浅性吸收,置换性吸收,炎症性吸与外伤类型的关系。方法从１９８４－１９９６年在北京医科大学附属口腔医院儿科就诊的２０１例前牙外伤发生牙震荡和牙移位患者的病历资料中选择７９例１５７颗无冠折根折的外伤牙,并且如果有牙松动者使用全牙Ｈｅ     

Combination injuries 3. The risk of pulp necrosis in permanent teeth with extrusion or lateral luxation and concomitant crown fractures without pulp exposure

Abstract – Aim: To analyze the influence of a crown fracture without pulp exposure on the risk of pulp necrosis (PN) in teeth with extrusion or lateral luxation. Material and methods: The study included 82 permanent incisors with extrusion from 78 patients (57 male, 21 female) and 179 permanent incisors with lateral luxation from 149 patients (87 male, 62 female). A total of 25 teeth with extrusion and 33 teeth with lateral luxation had suffered a concomitant crown fracture (infraction, enamel fracture or enamel‐dentin‐fracture). All the teeth were examined and treated according to a standardized protocol. Statistics: The risk of PN was analyzed separately for teeth with immature and mature root development by the Kaplan–Meier method, the log‐rank test and Cox regression (lateral luxation only). The level of significance was set at 5%. Risk factors included in the analysis were gender, age, crown fracture, and response to electric pulp test at the initial examination. Results: A concomitant crown fracture significantly increased the risk of PN in teeth with lateral luxation. For teeth with immature root development (hazard ratio: 10 [95% confidence interval (CI): 1.1–100] P = 0.04), the overall risk increased from 4.7% (95% CI: 0–10.8) to 40% (95% CI: 2.8–77.2). For teeth with mature root development [hazard ratio: 2.4 (95% CI: 1.4–4.2) P < 0.001], the overall risk increased from 65.1% (95% CI: 55.2–75.1) to 93% (95% CI: 85.5–100). In teeth with extrusion and mature root development, the overall risk of PN increased from 56.5% (95% CI: 37.7–75.4) to 76.5% (95% CI: 58.9–94) in case of a concomitant crown fracture, but the difference was not statistically significant (P > 0.05). Conclusion: A concomitant crown fracture without pulp exposure significantly increased the risk of PN in teeth with lateral luxation. This risk factor may be used to identify teeth at increased risk of PN following lateral luxation injury.     

Pulp canal obliteration after Le Fort I osteotomy

Abstract A longitudinal study of 51 patients was carried out to determine the frequency of pulp canal obliteration (PCO) after Le Fort I osteotomy for the correction of dentofacial anomalies and to analyse pre- and peroperative factors influencing the development of PCO. PCO developed in 14 (2.3%) of 617 maxillary teeth followed for an average period of 28 months (range 11–59). The highest frequency of PCO was demonstrated in canines (6.0%) and premolars (4.4%). Total PCO was present in 9 teeth and partial PCO in 5 teeth. PCO was more frequent among teeth adjacent to a vertical interdental osteotomy than in teeth with no relation to a vertical osteotomy (p< 0.0001). Change in blood supply after the operation was suggested to be responsible for PCO, although it might have been effected by the combined surgical and orthodontic treatment. Long-term follow-up, including periapical radiographs, of teeth with PCO is suggested, as pulp necrosis may develop many years after surgery.     

Healing of 208 intraalveolar root fractures in patients aged 7–17 years

Abstract – This retrospective study consisted of 208 root-fractured, 168 splinted and 40 not splinted incisors in young individuals (aged 7–17 years) treated in the period 1959–1973 at the Pedodontic Department, Eastman Institute, Stockholm. Clinical and radiographic analyses showed that 69 teeth (33%) had developed hard tissue (fusion) healing of fragments. Interposition of periodontal ligament (PDL) and bone between the fragments was found in 17 teeth (8%). Interposition of PDL alone was found in 74 teeth (36%). Finally, non-healing with pulp necrosis and inflammatory changes between fragments was seen in 48 teeth (23%). Various clinical factors were analyzed for their relationship to the healing outcome with respect to healing/no healing and type of healing (hard tissue versus interposition of bone and/or PDL). Immature root and positive pulp sensitivity at time of injury was found to be significantly related to both pulp healing and hard tissue repair of the fracture. The same applied to concussion or subluxation of the coronal fragment compared to luxation with displacement (extrusive or lateral luxation). This relation was also represented by the variable millimeter diastasis between fragments before and after repositioning. Repositioning appeared to enhance the likelihood of both pulp healing and hard tissue repair. A positive effect of splinting, splinting methods (cap splints or orthodontic bands with an arch wire) or splinting periods could not be demonstrated on either pulp healing or type of healing (hard tissue versus interposition of bone and/or PDL). In conclusion, the findings from this retrospective study have cast doubts on the efficacy of long-term splinting and the types of splint used for root fracture healing. It is suggested that the role of splinting and splinting methods be examined in further studies.     

Pulp and periodontal healing of laterally luxated permanent teeth: results after 4 years

Abstract – Aim: To evaluate the pulp and periodontal healing of laterally luxated permanent teeth. Material and methods: Patients presenting with lateral luxation of permanent teeth during 2001–2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root‐canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re‐examinations were performed after 1, 2, 3, 6, 12 and 48 months. Results: All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root‐canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4‐year re‐examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. Conclusions: Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices.     

Traumatized primary anterior teeth. Prognosis related to calcific reactions in the pulp cavity.

The frequency of a complicating pulp necrosis and the process of the physiologic root resorption were studied in traumatized primary teeth exhibiting partial or total pulp obliteration. The material comprised 88 incisors in 72 children aged 0.7--5.7 years (mean 2.9 years) at the time of injury. Trauma had resulted either in subluxation (25 teeth), or luxation (13 teeth), whereas the type of injury was unknown in 50 teeth. All cases were observed until eruption of the permanent incisors. Forty-four teeth initially displayed a reversible greyish color. The ultimate finding observed in all teeth was, however, varying degrees of yellow discoloration. Periapical pathologic findings indicative of pulp necrosis were observed in 9 teeth, from 1.6--4 years (mean 3 years) after the time of injury. Extraction was performed immediately, and none of the successional teeth showed developmental disturbances. The process of root resorption was classified as normal in all primary teeth. Subsequent eruption of the permanent successors occurred without any registered complications.     

年轻恒牙挫入性损伤的处理策略

年轻恒牙挫入性损伤是预后最差的牙外伤类型之一,常导致牙齿缺失,影响患儿的美观及健康.治疗方案通常包括观察再萌出、正畸牵引复位和外科复位3种;临床上应根据患牙的牙根发育情况及挫入程度,参考患儿及家长意愿,选择单独或结合使用上述3种治疗方案进行治疗.治疗后的主要并发症包括牙髓坏死、牙根吸收、牙槽骨边缘性吸收、根管闭塞等.尽...     

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.     

Pulpal healing after luxation injuries and root fracture in the permanent dentition

Pulpal healing patterns were studied in a clinical material of 637 luxated and 95 root-fractured permanent incisors followed routinely for up to 11 years. It was found that pulpal healing patterns could generally be divided into 3 groups according to the degree of injury sustained by the pulp: little, moderate or severe. Thus after luxation injuries, pulp survival could be without radiographic change (PS), with pulp canal obliteration (PCO) or nonhealing (pulp necrosis (PN]. After root fracture, similar healing patterns could be observed: healing by hard tissue union of fragments (HT), by connective tissue union of fragments (CT) or by nonunion due to interposition of granulation tissue between fragments (GT) resulting from PN of the coronal fragment. In both trauma situations, healing or nonhealing could be determined by type of luxation injury, stage of root development and type of fixation used (forceful application of orthodontic bands vs. passively applied acid-etch fixation). Pulpal healing complications (PN or GT) were based on clinical findings (coronal discoloration, loss of pulpal sensibility) and radiographic findings (resorption processes of the lamina dura at the root apex or at the level of the root fracture). However, in both injury groups the same changes could also be seen to be intermediate steps in the pulpal healing process. Based on findings from these studies, hypotheses for the mechanics of pulpal healing are proposed as well as guidelines for acute and later treatment of dental luxations, root fractures and the diagnosis of healing complications.     

Prognosis of luxated permanent teeth — the development of pulp necrosis

Abstract A population of 400 patients, comprising 637 luxated permanent teeth was studied prospectively with respect to the development of pulp necrosis after luxation injuries. The patients were treated for traumatic dental injuries over a period of 10 years. While initial treatment was provided according to established treatment guidelines by the attending oral surgeon at the emergency room, follow-up examination and treatment was provided by one oral surgeon. It appeared that pulp necrosis occurred soon after injury, within 3 months after concussion, within the 1st yr after subluxation and extrusion, and might be diagnosed up to 2 yr after lateral- and intrusive luxation. While many factors, when considered one at a time, were found to have a significant or nearly significant died on the development of pulp necrosis (i.e. type of injury, age of patient, stage of root development, degree of dislocation, reduction/repositioning procedure, type of fixation, restorations in place at the lime of injury), a multivariate regression analysis revealed that when the type of injury (diagnosis) and stage of root development were taken into account, the effect of other factors was no longer significant. The risk of pulp necrosis increased with the extent of injury, i.e. concussion and subluxation represented the least risk, followed in ascending order by extrusive-, lateral-, and intrusive luxation. Moreover, teeth with completed root formal ion demonstrated a greater risk of pulp necrosis than teeth with incomplete root formation. No treatment effect could be demonstrated. However, as treatment was performed according to established guidelines, which might introduce bias, it would appear justified to conduct randomized clinical studies in order to determine the value of different forms of treatment (e.g. reduction and fixation of luxated teeth) to improve the prognosis with respect to the development of pulp necrosis after injury. In conclusion, the major factors influencing development of pulp necrosis after luxation injuries appear to be the extent of the initial injury to the pulp and periodontium, as reflected by the type of luxation, and the repair potential of the injured tooth, as reflected by the stage of root development.     

Transient apical breakdown and its relation to color and sensibility changes after luxation injuries to teeth

Abstract In examining a population of 637 luxated permanent teeth, it was found that 27 teeth (4.2%) demonstrated apical breakdown in the form of either a pronounced radiolucency which appeared spontaneously some time after injury, or a persistent expansion of the periodontal ligament space (PDL) over an extended interval after injury, which at later follow-up controls had either returned to normal without further radiographic change or was accompanied by surface resorption and/or pulp canal obliteration without intervening treatment. Two of the 27 teeth demonstrated radiographic change alone, while the remaining 25 demonstrated color and/or electrometric sensibility-changes as well. Twenty-three teeth had fully-formed roots whose apices were either closed or half-closed at the time of injury. Five had roots which were fully formed, but with an open apex; the remaining tooth had three-quarter root formation. The injuries were moderate, the majority being extrusion or lateral luxation, affecting both pulpal and periodontal structures. Based on clinical findings, the following hypothesis is proposed: Transient apical breakdown appears to be a phenomenon linked to the repair processes in the traumatized pulp or pulp and periodontium of luxated mature teeth which returns to normal when repair is complete. Whether this is related to a transitory infection and/ or removal of necrotic traumatized tissue cannot be evaluated from the material available.     

A retrospective study of 889 injured permanent teeth

Abstract – The aim of this study was to investigate pre‐injury factors, causes of dental injuries and healing complications after traumatic injuries to permanent teeth. The analysed sample comprised 889 permanent teeth of 384 patients, who were treated in the Dentistry Department in Faculty Hospital in Pilsen. Enamel‐dentin fractures [233 teeth (26.2%)] and lateral luxations [207 teeth (23.3%)] were the most frequent injuries. The age of the patients at the time of injury varied between 7 and 65 years. Predominantly, children were affected [587 injured teeth (66.0%)]. The most frequent causes of injuries in patients older than 11 years were various sport activities, predominantly bicycling. Pulp necrosis was observed in 239 teeth (26.9%). It was the most frequent post‐traumatic complication in all types of dental traumas. Teeth with a completed root formation demonstrated a higher prevalence of pulp necrosis than teeth with an incomplete root formation in all types of luxation injuries. External root resorption was observed in 144 teeth. The rate of inflammatory resorption differed between the various types of luxation injuries (extrusive luxation 5.6%, lateral luxation 11.6%, intrusive luxation 33.3%). Following avulsion and replantation, active inflammatory resorptions were diagnosed in 13 (26.5%) of 49 replanted teeth and ankylosis/replacement resorptions were observed in 21 (42.9%) of 49 replanted teeth. After avulsion, primarily, immature teeth were affected by these complications. Within the observation period of 5 years, 39 teeth (4.4%) had to be removed (16 teeth with root fractures, 19 avulsed and replanted teeth, 3 luxated teeth, 1 tooth with crown‐root fracture).     

Prognosis and complications of immature teeth following lateral luxation: A systematic review

Background/Aims

Lateral luxation injuries are a type of traumatic dental injury in which the tooth becomes displaced in the palatal/lingual or labial direction. This injury is common among children and can result in pulp canal obliteration or pulp necrosis. The objective of this systematic review was to gather existing data on lateral luxation injuries to immature teeth to evaluate their overall prognosis.

Methods

A systematic search was conducted using Medline, Pubmed, Scopus, Lilacs, EMBASE and Cochrane databases in October 2017. Reference lists were also hand‐searched to identify additional literature. Prospective and retrospective observational studies were included. A total of 502 articles were screened and six articles were included in the study.

Results

Pulp canal obliteration was the most frequent complication of immature teeth with lateral luxation (31.3%). This was followed by pulp necrosis (17.5%), inflammatory resorption (5.7%), and surface resorption (3.2%). Due to the heterogeneity of the studies, a meta‐analysis was not attempted. There was great variation in the reported outcomes among the studies.

Conclusion

Accurate prognosis evaluation of traumatic dental injuries is difficult due to the nature of current studies being retrospective or prospective cohort studies. Lateral luxation is a common traumatic dental injury and has life‐long concerns for a patient. It is important for future studies to report on the same outcomes to increase the quality of evidence regarding prognosis and treatment interventions, not only for lateral luxation injuries, but for all traumatic dental injuries.     

Clinical outcomes for permanent incisor luxations in a pediatric population. III. Lateral luxations

Abstract –  A longitudinal outcome study was designed to identify variables that influenced tooth survival as well as pulpal and periodontal outcomes of laterally luxated permanent maxillary incisors of children and adolescents. All cases were treated between June 1988 and June 1998 in a teaching hospital clinic. Clinical and radiographic data were collected for 42 patients (26 males, 16 females) that represented 58 permanent maxillary incisors. Mean age at the time of injury was 11.4 years (range: 6.3–17.8 years). Mean follow-up time was 1460 days (range: 183–3905 days). In the entire sample ( n  = 58), no incisors required extraction. Survival analysis and logistic regression were used to identify variables significantly related to the survival and healing outcomes of these incisors. Pulp necrosis (PN) (40%) and pulp canal obliteration (PCO) (40%) were common healing complications. Proportional hazards (Cox) regression showed that PN develops within the first year. Logistic regression demonstrated that root development ( P  = 0.3, PN; P  = 0.8, PCO) and extent of lateral luxation ( P  = 0.5, PN; P  = 0.9, PCO) were not significantly related to PN and PCO. This study provides the first report of incisor survival in children and adolescents following lateral luxation injuries.     

Transient apical breakdown of a discoloured maxillary central incisor during orthodontic treatment: A case report

Transient apical breakdown (TAB) appears to be a repair process taking place in the pulp and periapical area of traumatised teeth which may display crown discoloration and have no responses to pulp sensitivity tests. Few TAB cases induced by orthodontic forces have been reported so far. Presented is a case report in which TAB occurred on the maxillary right central incisor during orthodontic treatment. The affected tooth suddenly displayed crown discoloration and had no response to pulp testing at 6 weeks after the placement Invisalign Clear Aligner appliances. Condition of the discoloured tooth was monitored by periodic recall examinations without any active treatment. Six months after the occurrence of discoloration, the affected tooth recovered to its original shade and responded normally to pulp sensitivity tests.