Pulp canal obliteration in an unerupted permanent incisor following trauma to its primary predecessor: a case report

Abstract  – Trauma to a primary tooth may result in damage to the underlying developing permanent tooth bud because of the close proximity between the root of the primary tooth and its permanent successor. We report an unusual case where injury to the primary dentition resulted in pulp canal obliteration (PCO) of a permanent maxillary central incisor prior to its eruption. The other permanent maxillary central incisor was diagnosed as malformed because of trauma to the primary dentition at an earlier age. The occurrences of PCO or crown malformation dose not routinely disrupt the eruption of those teeth. Periodic assessment is required to determine the need for endodontic intervention.     

Periodontal ligament tissue reactions to trauma and gingival inflammation

Abstract The aims of the present study were to analyze (i) which tissue changes may occur in the zone of co-destruction to better understand why trauma from occlusion may induce additional attachment loss, and (ii) whether changes occur in the periodontal ligament tissue when an inflammatory lesion (ICT) approaches the periodontal ligament space. 16, 1-year-old beagle dogs, were selected and divided into 2 groups, group A and group B, consisting of 6 and 10 dogs, respectively. In group A, on day 0. a bucco-lingual jiggling type movement was induced resulting in increasing tooth mobility at P₃ (test tooth) by the application of an orthodontic elastic which traversed the buccal surface of the crown of the test tooth. The elastic was exchanged either in a buccal or in a lingual position 2x a week during a 3-month period. ₃P served as non-jiggled control tooth. Tooth mobility measurements were recorded on days 0, 30, 60, 90. A plaque control regimen was maintained until the end of the experiment (day 90). On day 90, biopsies including P₃ and ₃P were harvested. The dogs representing group B, were divided into 2 subgroups of 5 each, group BI and group BII. On day 0, a 4-month period of experimental periodontal tissue breakdown was initiated by placing cotton floss ligatures submarginally around the mandibular fourth premolars (₄P₄) in group BI and around the mandibular third premolars (₃P₃) in group BII. All ligatures were exchanged, replaced 1X every month, and on day 120 permanently removed. On the same day, biopsies included ₄P₄ were harvested. Following supragingival debridement ₃P₃ were allowed to accumulate plaque until the end of the study (day 225). On this occasion, biopsies including ₃P₃ were harvested. The results of the histological measurements revealed that in the most coronal portion of the periodontal ligament of teeth exhibiting increasing mobility, there was an increased width, a reduced % tissue volume of collagen, and an increased volume of vascular structures and leukocytes. Furthermore, the number of osteoclasts bordering this portion of the alveolar bone was increased and the number of collagen fibers inserting into the root cementum and into the alveolar bone was reduced. It was also demonstrated that in teeth with normal mobility, the position of the gingival ICT failed to influence the composition of the tissue within the coronal portion of the periodontal ligament.     

Developmental disturbances of permanent teeth following trauma to the primary dentition

The topographic relationship of the apices of the primary teeth to the permanent tooth germs explains the potential for possible developmental disturbances of the permanent teeth after injuries to their predecessors. The anatomical, histologic and clinical aspects of permanent tooth malformation following trauma to the primary teeth are described. One hundred and fourteen children with originally 255 traumatized primary teeth have been re-examined (with an average period of 5.1 years after the trauma) to assess any developmental disturbances of the corresponding permanent teeth. Twenty-three per cent of partially or completely erupted permanent teeth showed developmental disturbances. The most frequent malformation was enamel hypoplasia including enamel discoloration and/or enamel defects. The highest prevalence of developmental disturbances of permanent teeth was found after intrusive injuries of primary teeth.     

Change in supporting tissue following loss of a permanent maxillary incisor in children

Alveolar bone resorption is an inevitable consequence of tooth loss and may be detrimental to long-term dental aesthetics and function. The aim of the present study was to quantify the degree of tissue resorption following the loss of a permanent incisor in a young population. The study group comprised 11 boys and five girls who all required the extraction of a permanent maxillary central incisor due to trauma-related sequelae. Mean age at tooth loss was 10.8 years. Upper alginate impressions were taken at regular intervals following tooth loss and were cast in yellow dental stone. Study models were sectioned longitudinally through the mid-point of both the maxillary incisor socket and the contra-lateral incisor to provide a thin plaster section. Digital photographs were acquired of the edentulous (A1) and dentate (A2) surfaces of this section and image analysis software was employed to quantify the surface area of both A1 and A2. At 3 months postextraction, mean A1 was 15.7% less than mean A2. By 6 months mean A1 had further reduced and was 25.3% less than that of the corresponding dentate alveolus. However, at subsequent time intervals following tooth extraction (>6 months), tissue loss appeared to stabilise with an overall reduction in tissue area remaining at 22%. This reduction in supporting tissue area was found to be highly statistically significant (P = 0.002, anova). Furthermore, girls appeared to have an overall greater degree of tissue loss than boys (P = 0.015). Further research is indicated to explore factors influencing the degree of tissue loss following incisor extraction and the benefit of therapeutic interventions in limiting this resorption.     

An unusual developmental disturbance of an unerupted permanent incisor due to trauma to its predecessor – a case report

Abstract –  Developmental disturbances of unerupted permanent tooth result from trauma to primary tooth as there is a close proximity between the root of the primary tooth and its permanent successor. The damage to the unerupted permanent tooth occurs by the transmission of traumatic forces to the permanent tooth germ. In the present case, however, a developmental disturbance on the permanent maxillary central incisor resulting from a direct effect of the inversely intruded primary maxillary central incisor is presented. The intruded tooth was extracted under general anesthesia. Upon eruption of the permanent central incisor, a localized crown malformation along with enamel hypoplasia which was not classified as a developmental disturbance before was observed. The damaged sites were restored with a light-cured composite resin.     

中切牙外伤拔除的正畸治疗

目的 探讨正畸拔除上颌单侧中切牙矫治模式的可行性及临床治疗的要点.方法 从40例切牙外伤正畸病例中,选出患者19例.其中安氏Ⅰ类错（牙合）10例,安氏Ⅱ类错（牙合）7例,安氏Ⅲ类错（牙合）2例;男16例,女3例,平均年龄14.5岁,均存在牙量与骨量不调需拔牙矫治病例.所有患者采取拔除外伤中切牙及其它三个象限第一前磨牙模式进行矫治.矫治后对临床资料做回顾性的研究,并进行临床疗效评价.结果 19例患者均取得较好的治疗效果,矫治后拔牙间隙关闭,前牙覆（牙合）覆盖正常,中线基本正中,侧貌得到改善.采用治疗前后配对t检验方法,发现牙性指标4项：U1-NA（27.5°至23.3°）、L1-NB（36.4°至32.5°）、L1-MP（97.2°至93.5°）角度减少,表示上下中切牙的倾斜度减小,U1-L1（11.83°至124.4°）角度增加,表示上下中切牙的凸度减少;软组织指标2项：上唇凸点-E线距（Ls-E）从3.5mm减小到1.2mm、下唇凸点-E线距（Li-E）从4.1mm减少到1.5mm,差异均有统计学意义（P＜0.05）.结论 遵循个体化原则,用Bolton指数指导设计和有效支抗控制,非常规拔牙模式矫治,能够达到预期目的.     

Enamel changes in permanent teeth after trauma to their primary predecessors

abstract – The frequency of developmental disturbances in the permanent dentition due to traumatic injuries to primary teeth was examined in a Danish population sample consisting of 487 schoolchildren 9–17 years old. Of these children, 147 (30%) had a history of traumatic injuries to the primary dentition. Frequencies of 57.8% and 45.3% of developmental disturbances were found in the trauma and in the non-trauma group, respectively. The folloing types of developmental disturbances were more frequent in the trauma group than in the non-trauma group: (1) internal white enamel hypoplasia with a diameter of 0.5 mm or more, (2) internal and external white and yellow-brown enamel hypoplasia, (3) white and yellow-brown enamel hypoplasia and horizontal enamel hypoplasia. Internal white enamel hypoplasia with a diameter of less than 0.5 mm, and generalized internal and external white enamel hypoplasias were found with the same frequency in the two groups. About 10% of enamel hypoplasias in anterior teeth are due to trauma.     

Survival of intentionally retained permanent incisor roots following crown root fractures in children

Retaining tooth roots, following crown loss, confers a number of benefits including the preservation of alveolar bone. Intentional root retention in adults has been widely investigated but little is known about this treatment approach in children. Therefore, the aim of the present study was to investigate the clinical outcomes associated with permanent anterior root retention in a young population. The study group comprised 53 children who had received treatment in the paediatric dentistry clinic, Charles Clifford Dental Hospital, Sheffield, UK, over the past 10 years, following a complicated crown root fracture of a permanent maxillary incisor at or below the gingival margin. Data relating to patient age at crown root fracture, gender, previous trauma history, tooth vitality, treatments performed and clinical outcomes were obtained retrospectively using patient records. The mean age of the subjects at initial crown root fracture was 12.1 years (range 8.3–15.8 years) and there were more than twice as many males (n = 37, 70%) as females (n = 16, 30%). In just over half of the cases seen (n = 29, 54%), the tooth involved was already nonvital at the time of crown root fracture. For the majority of these nonvital teeth (n = 27, 93%), primary treatment had comprised placement/replacement of a calcium hydroxide root dressing. The remaining two teeth did not require root treatment as a satisfactory gutta percha root filling was already present. A variety of treatments was undertaken for the 24 vital roots: in 15 (63%) cases the pulp was extirpated and calcium hydroxide placed; three (12%) cases were subject to a pulpotomy; five (21%) cases were left untreated with the hope that vitality would be maintained following gingival healing and in one case the radicular pulp was extirpated and immediately obturated with gutta percha. The mean time that the roots were kept under review was 2.6 years (± 1.57, range 0.6–6.8). During this period, only five roots (9%) had to be removed due to persistent periapical infection. There were no complications associated with the five cases where vital root submergence had been permitted but all three cases which had initially undergone a pulpotomy subsequently presented with pulpal necrosis necessitating pulpal extirpation and calcium hydroxide therapy. These findings indicate that efforts to retain permanent anterior roots in a young population are justified in view of the high clinical success rate of over 90% over a 2‐year period.     

Vascular reactions in the periodontal ligament incident to trauma from occlusion

Abstract The experiments were performed in 13 dogs; nine of the animals had initially a healthy periodontium and four had experimental periodontitis. Trauma from occlusion was created in all dogs according to a technique described previously. The dogs were sacrificed after 7, 14, 30 and 180 days of the experiment. Prior to sacrifice colloidal carbon was injected intravenously. The degree of vascular labelling and leucocyte infiltration as well as osteoclastic activity and the size of the marginal periodontal ligament were assessed in biopsy sections. The findings showed that dogs with a healthy periodontal lesion (Group A) differed in their reactions to a jiggling type of occlusal trauma when compared to dogs with an established periodontal lesion (Group B). Whereas the periodontal ligament in Group A had become adapted to the altered occlusion by the end of 6 months of experiment, that of Group B still showed increased vascular leakage, leucocyte migration and osteoclastic activity.     

An investigation of root-fractured permanent incisor teeth in children

Abstract  – The aim of this retrospective study was to determine the type of healing which occurred in root-fractured permanent incisor teeth in children. The objectives were to determine whether gender, age, stage of root development or location of the fracture affected the healing type. The method involved careful scrutiny of clinical records and radiographs of children who attended a unit of paediatric dentistry in a dental hospital. Relevant information was entered onto a data collection sheet. The results were tabulated and analysed by the χ ²-tests using the SPSS statistical package. The results are based on 34 root-fractured teeth in 33 children aged 8–15 years. Root development was incomplete in 27 of the root-fractured teeth and complete in seven teeth. A good healing outcome was seen in 27 (79.4%) of the teeth and poor healing in 7 (20.6%). The only factor which was found to be statistically significantly related to healing was the stage of root development. It can be concluded that root-fractured teeth with immature roots have a better chance of showing good healing than teeth with mature roots.     

Periodontal healing of extracted dogs' teeth air-dried for extended periods and soaked in various media

Abstract The aim of this study was to determine the periodontal healing of replanted dogs’ teeth which, after extended extra-oral dry times, had been soaked in various media before replantation. Incisors and premolars of beagle dogs were root canal treated, extracted and bench dried. The teeth were grouped according to dry times of 30, 45 and 60 minutes. Each group of teeth was soaked in one of three media, Hank's balanced salt solution, Via Span (Belzer UW-CSS, Dupont Pharmaceuticals), or Conditioned Medium (supernatant of confluent culture of human gingival fibroblasts) for 30 minutes before replantation. Controls consisted of teeth extracted and replanted without drying or soaking (negative control), and bench-dried teeth replanted without soaking in the media (positive control). The dogs were killed 6 months after replantation of the teeth, which were prepared for histologic evaluation. Five um cross-sections (every 70 Jim) of the root and surrounding tissue were evaluated for healing/resorption according to Andreasen's criteria. The best healing occurred for the roots which had been immediately replanted. Healing in the positive control groups decreased with increased dry time. For the 30–minute dry time groups, soaking in media had no beneficial effect on periodontal healing compared with the controls. Soaking in ViaSpan resulted in an increased healing incidence for both the 45- and 60- minute bench-dried groups while soaking in the other media had no consistent beneficial effect. It appears from this study that an avulsed tooth that has been left dry for 30 minutes should be replanted immediately without soaking. However, teeth that have been dry for 45 or 60 minutes would benefit from soaking for 30 minutes in ViaSpan.     

Pulpal and periodontal reactions of immature permanent teeth in the dog to intrusive trauma

Abstract Pulpal and periodontal tissues of immature incisors of 10 dogs were radiographically and histopathologically evaluated immediately, 7, 15, 30 and 60 days after experimental intrusion induced by mechanical blows. Forty upper central and mesial lateral incisors showing incomplete root formation on radiographs were submitted to intrusive force. After the observation periods, the dogs were killed, two at a time. The hemi-maxilas were removed and processed for histopathologic examination. The traumatized teeth showed accelerated apical formation with reduced radicular length. Pulpal vitality was maintained and the subjacent tissues did not present irreversible changes. All traumatized teeth re-erupted spontaneously.     

Periodontal conditions of teeth adjacent to extraction sites

The purpose of the present clinical study was to evaluate the effect of tooth extractions on the periodontal conditions of adjacent teeth. 40 patients were selected for the study. Prior to the extractions, baseline data of the adjacent teeth were obtained. Plaque (PII) and gingival indices (GI), pocket probing depths and probing attachment levels were scored. In addition, the alveolar bone height was determined radiographically in relation to the CEJ adjacent to the extraction sites. The contralateral side of the jaw, where no tooth had to be removed, was examined as a control. A limited hygienic phase (scaling and root planing of all surfaces examined) was performed immediately prior to the extractions. Using the same parameters, all sites were reexamined 2-4 months and 6-9 months following the extractions. After the hygienic phase, the teeth adjacent to the extraction sites indicated a decrease in the pocket probing depths by 0.5 to 1.5 mm. In shallow pockets (1-3 mm), this decrease was less pronounced than in moderate to deep pockets (4-9 mm), where it was composed of shrinkage of the gingival tissues and gain of probing attachment. The radiographic level of the bony alveolar crest in relation to the CEJ of the adjacent teeth was not altered by the extraction procedure. The oral hygiene performances of the patients were not influenced during the 9-month observation period. Therefore, neither PII nor GI scores showed relevant improvements.(ABSTRACT TRUNCATED AT 250 WORDS)     

Periodontal healing in teeth with periapical lesions

Abstract The purpose of the present investigation was to compare clinical periodontal healing in periodontally involved teeth with and without pulpal pathosis. The investigation was conducted as a retrospective study on a consecutive referral population. The periapical conditions in endodontically involved single-rooted teeth from a selected patient sample were evaluated and correlated with their periodontal healing pattern. Multiple regression analysis of the registered variables showed that initial mean pocket depth and time elapsed after treatment significantly influenced change in pocket-depth. Non-surgical treatment of periodontal pockets exceeding 2.5 mm in teeth with horizontal marginal defects, over the observation period, showed significantly reduced mean pocket depth reduction in teeth with periapical pathology compared to teeth without periapical pathology. It was, furthermore, evident that proximal restorations, abutments for fixed bridges and root fillings with and without dowels did not significantly influence pocket depth reduction in the present material. It was concluded, based on the present results, that a root-canal infection, evident as a periapical radiolucency, if left untreated may in the long term perspective result in retarded or impaired periodontal healing following periodontal therapy and, consequently, should be given appropriate consideration when coordinating endodontic therapy and periodontal treatment.     

A method of studying the effects of reduced alveolar support on the sensibility to axial force on the incisor teeth in humans

Abstract A method has been developed for measuring the threshold level of sensibility to axial pressures applied to the incisor teeth in man. Eight subjects were investigated, four with normal alveolar support and four with support reduced by up to 60 % as a result of chronic periodontal disease. Reduced alveolar support appears to have no1 significant effect on the threshold of perception. All subjects had a lower threshold for the removal of force than for its application. Infiltration of local anaesthetic labially over the test tooth resulted in failure to feel forces previously recognised, thus confirming the role of the periodontal receptors in force perception.     

Thermal trauma to teeth

Abstract The literature is reviewed with respect to several thermal loading situations and their influence on the temperature field in teeth. Breathing, food consumption, and dental treatment are processes disturbing the thermal balance in the oral cavity. The tooth temperature will be affected. These thermal changes result in a physical after-effect on enamel, dentin, and restorative materials, as well as in a histological change of the pulp tissue. Postoperative discomfort is another after-effect reported as a result of dental treatment. Recommendations concerning cooling technique and the use of a cement base are given to avoid this discomfort. In the literature reviewed, attention is mainly focused on temperature within teeth. However, the underlying thermal processes are important in the reported after-effects. It is concluded that more attention should be paid to this phenomenon in future research.     

Variation in root length of the permanent maxillary central incisor

abstract — A metric study was performed on radiographs of permanent maxillary central incisors of a normal Swedish population of 1,038 children. The normal distribution of the root lengths revealed two extreme groups: 2.4% had short roots, formerly described as Short Root anomaly, most prevalent among girls with a boy:girl ratio of 1:2.6. In the opposite extreme group, i.e., with exceptionally long roots comprising 2.3% of the children, the boys dominate with a boy:girl ratio of 5:1. Clinical evidence suggests that variation in root length is of genetic origin.     

Influence of trauma from occlusion on progression of experimental periodontitis in the beagle dog

Abstract The experiments were performed in six beagle dogs fed a soft diet which allowed dental plaque formation. During a pre-experimental period of 7 weeks, periodontitis was induced by (1) surgically creating a bony pocket and (2) adapting a copper band to the exposed tooth surface. Two dogs were sacrificed at the end of this period and tissue sections were prepared for histological examination. In the remaining four dogs, trauma from occlusion was produced on the left mandibular fourth premolar by the installation of a cap splint and a bar device. The contralateral premolar served as a control. At the start of, and at regular intervals during, an experimental period of 180 days, tooth mobility, gingival inflammation and plaque accumulation were assessed. After sacrifice, radiographs were taken of test and control tooth regions and histological sections analysed regarding the width of the marginal periodontal ligament space and the degree of apical downgrowth of the gingival pocket epithelium. Only the test teeth showed a gradually increasing horizontal mobility, but gingival inflammation and Plaque Index scores were similar on test and control sides. Radiographs revealed (1) horizontal bone loss in both test and control areas, and (2) angular bone destruction only in test areas. Histological sections showed that the degree of apical proliferation of the pocket epithelium was more pronounced in test than in control regions.