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Notes: Abstract  – Root resorption is known to be the most relevant complication determining the long-term prognosis of allotransplanted teeth, and it is initiated during the first few postoperative months. The aim of the present study was to quantitatively assess the dynamics of the periodontal ligament (PDL) and pulpal healing reactions during the first 8 weeks after allotransplantation of mature teeth. The material comprised 112 maxillary central and mandibular lateral incisors of 28 mature green Vervet monkeys, immunogenetically untested, and only matched according to the size of the grafts. Donors and recipients exchanged simultaneously both maxillary incisors and one mandibular incisor, whereas the contralateral mandibular incisors were autotransplanted as controls. At random, every second maxillary allograft was endodontically treated preoperatively. Histoquantitative analysis of the PDL and pulpal healing reactions was carried out after 1, 2, 4 and 8 weeks on serial cross-sections of the grafts in 6, 6, 6 and 8 monkeys, respectively. Necrosis zones in the PDL were prominent in both auto- and allografts after 1 week. Inflammation in the PDL dominated healing in all types of grafts 1 week after transplantation, whereas it subsided significantly after 2 weeks in autografts compared to allografts (P = 0.005). Inflammatory resorption (IR) became prominent after 4 weeks in autografts and this remained stationary. In contrast, IR initiated significantly earlier in allografts compared to autografts after 2 weeks (P = 0.007), and this type of resorption was further increasing in allografts after 4 and 8 weeks. Endodontic treatment, however, reduced IR nearly totally in the allografts with time. Replacement resorption (RR) was nearly absent in autografts. In contrast, allografts showed increasing appearance of RR with time, initiating at 4 weeks. By removing IR from the allografts by endodontic treatment, RR was unmasked significantly at 4 weeks (P = 0.02) and dominated most of the periodontal ligament (70%) after 8 weeks (P = 0.0004). Within the 8 postoperative weeks autografts showed healing with increasing amount of normal PDL reaching significantly higher levels compared to allografts already after 2 weeks (P = 0.02), with increasing differences thereafter. In most allografts, the normal PDL occupied less than 10% of the entire root surface and was located in the supra-alveolar cervical region. Downgrowth of periodontal pocket epithelium was absent or found very infrequently in all groups irrespective of type, time and treatment.In conclusion, the healing of allo- and autotransplanted mature teeth differed significantly on several aspects during the first 8 postoperative weeks. The recorded differences included a higher amount of inflammation in the PDL of allografts after 2 weeks, inflammatory resorption from the second week, and replacement resorption dominating in the eighth week, indicated that an immunologic stimulus for root resorption existed in the allogenic PDL apart from the pulp. Furthermore, specific healing reactions was found in the cervical region with almost identical gingival healing in auto- and allografts.

Notes: Abstract – The objective of this in vitro study was to investigate the impact strength of anterior teeth that have been fractured and restored by bonding with a dentin-bonding agent and a composite resin. Twenty sheep central incisors were divided into two groups, 10 in each. One group (intact teeth) served as the control and the teeth in the other group were fractured and then bonded with a bonding agent and a low-viscous composite resin. The specimens were tested in a modified impact-testing machine (pendulum type). The mean impact strength of the intact teeth was 30.6±2.16 KJ/m2 and of the bonded teeth was 30.2±1.86 KJ/m2. Statistics revealed that the two means were not significantly different. The results related well with the fracture strength obtained by loading intact and bonded teeth at constant but low speed until fracture. It was concluded that bonding fragments to the remaining tooth structure may restore the tooth to its original strength, measured at modest velocities of the applied force. In other words, reattaching the original coronal fragment of traumatised fractured anterior teeth restored with One-Step dentin bonding system and Æliteflo composite resin would withstand a second trauma to the same extent as intact teeth.

Notes: Abstract –  This is the second part of a retrospective study of 400 root-fractured permanent incisors. In this article, the effect of various treatment procedures is analyzed. Treatment delay, i.e. treatment later than 24 h after injury, did not change the root fracture healing pattern, healing with hard tissue between fragments (HH1), interposition of bone and/or periodontal ligament (PDL) or pulp necrosis (NEC). When initial displacement did not exceed 1 mm, optimal repositioning appeared to significantly enhance both the likelihood of pulpal healing and hard tissue repair (HH1). Significant differences in healing were found among the different splinting techniques. The lowest frequency of healing was found with cap splints and the highest with fiberglass or Kevlar® splints. The latter splinting procedure showed almost the same healing result as non-splinting. Comparison between non-splinting and splinting for non-displaced teeth was found to reveal no benefit from splinting. With respect to root fractures with displacement, too few cases were available for analysis. No beneficial effect of splinting periods greater than 4 weeks could be demonstrated. The administration of antibiotics had the paradoxical effect of promoting both HH1 and NEC. No explanation could be found. It was concluded that, optimal repositioning seems to favor healing. Furthermore, the chosen splinting method appears to be related to healing of root fractures, with a preference to pulp healing and healing fusion of fragments to a certain flexibility of the splint and possibly also non-traumatogenic splint application. Splinting for more than 4 weeks was not found to influence the healing pattern. A certain treatment delay (a few days) appears not to result in inferior healing. The role of antibiotics upon fracture healing is questionable.

Notes: Abstract –  According to treatment type, root-fractured teeth with pulp necrosis or exposed pulps were divided into five groups, group 1: 17 teeth in which the root canal of the coronal fragment only was filled with gutta-percha (GP); group 2: seven teeth in which the root canals of the coronal and apical fragments were both filled with GP; group 3: 19 teeth in which the coronal fragment was filled with GP and the apical fragment was surgically removed; group 4: 68 teeth where the root canal of the coronal fragment was treated with calcium hydroxide and subsequently filled with GP; and group 5: five vital teeth with root and concomitant crown fractures in which the exposed pulps were treated by partial pulpotomy. The frequency of periodontal healing was 76% in group 1, zero in group 2, 68% in group 3 and 86% in group 4. Compared with groups 1 and 2 combined, healing in group 4 was significantly more frequent. In groups 1, 2 and 4, failures occurred significantly more often in teeth showing overfilling, i.e. protrusion of GP into the space between the fragments, compared with teeth without overfilling. All five teeth in group 5 showed healing. It was concluded that root canal filling with GP of the coronal fragment only, with or without surgical removal of the apical fragment, can be successful in selected cases. Treatment of the root canal with calcium hydroxide followed by GP filling appears to be the treatment of choice in root-fractured non-vital teeth. Partial pulpotomy of exposed pulps in five teeth showed results similar to root-unfractured teeth with pulp exposure treated with this technique.

Notes: Abstract  – The effect of temperature of various storage media and at varying storage periods upon periodontal ligament (PDL) and pulpal healing after tooth replantation was examined in green vervet monkeys (Cercopithecus aethiops). Mandibular lateral incisors with mature root formation were extracted and kept in dry storage at 22, 4 and −18 °C; in saline at 37, 22, 4 and −18 °C; or in saliva (i.e. in the buccal vestibule) at 37 °C for either 60 or 120 min prior to replantation. The animals were sacrificed 8 weeks after replantation and the replanted teeth examined histometrically. The following histological parameters were registered for each tooth: normal PDL, surface resorption, inflammatory resorption, replacement resorption (ankylosis), downgrowth of pocket epithelium, periapical inflammatory changes, and the extent of vital pulp. A total of 125 replanted teeth were examined. Storage in saliva at 37 °C showed a similar amount of normal PDL compared to saline storage for both 60 and 120 min. Saline storage for 60 or 120 min showed no difference in the extent of normal PDL when storage was compared at 37, 22 and 4 °C. However, storage at −18 °C resulted in significantly less normal PDL than storage at other temperatures. Dry storage for 60 min showed significantly less root resorption at 4 °C compared to 22 °C. Furthermore, dry storage at −18 °C showed significantly less normal PDL than storage at 4 °C. When the dry storage period was extended to 120 min, no difference was found between 22, 4 and −18 °C. It is concluded that the temperature (above 0 °C) of the storage medium is of importance only for dry storage and in such a situation only for shorter extra-alveolar periods, i.e. for 60-min storage and not for 120 min, where extensive destruction of the PDL always takes place. It is suggested that the temperature effect of 4 °C could be related to less evaporation from the PDL and thereby less damage to the PDL cells or a strict temperature effect upon cell metabolism. Pulp healing in all the cases was limited to the entrance of the pulp canal, and no significant pattern was found between storage media, time and temperature.

Notes: Abstract –  This retrospective study consisted of 400 root-fractured, splinted or non-splinted incisors in young individuals aged 7–17 years (mean = 11.5 ± 2.7 SD) who were treated in the period 1959–1995 at the Department of Pediatric Dentistry, Eastman Dental Institute, Stockholm. Four hundred of these root fractures were diagnosed at the time of injury; and 344 teeth were splinted with either cap-splints, orthodontic appliances, bonded metal wires, proximal bonding with composite resin or bonding with a Kevlar® or glass fiber splint. In 56 teeth, no splinting was carried out for various reasons. In the present study, only pre-injury and injury factors were analyzed. In a second study, treatment variables will be analyzed. The average observation period was 3.1 years ± 2.6 SD. The clinical and radiographic findings showed that 120 teeth out of 400 teeth (30%) had healed by hard tissue fusion of the fragments. Interposition of periodontal ligament (PDL) and bone between fragments was found in 22 teeth (5%), whereas interposition of PDL alone was found in 170 teeth (43%). Finally, non-healing, with pulp necrosis and inflammatory changes between fragments, was seen in 88 teeth (22%). In a univariate and multivariate stratified analysis, a series of clinical factors were analyzed for their relation to the healing outcome with respect to pulp healing vs. pulp necrosis and type of healing (hard tissue vs. interposition of bone and/or PDL or pulp necrosis). Young age, immature root formation and positive pulp sensibility at the time of injury were found to be significantly and positively related to both pulpal healing and hard tissue repair of the fracture. The same applied to concussion or subluxation (i.e. no displacement) of the coronal fragment compared to extrusion or lateral luxation (i.e. displacement). Furthermore, no mobility vs. mobility of the coronal fragment. Healing was progressively worsened with increased millimeter diastasis between fragments. Sex was a significant factor, as girls showed more frequent hard tissue healing than boys. This relationship could possibly be explained by the fact that girls experienced trauma at an earlier age (i.e. with more immature root formation) and their traumas were of a less severe nature. Thus, the pre-injury or injury factors which had the greatest influence upon healing (i.e. whether hard tissue fusion or pulp necrosis) were: age, stage of root development (i.e. the size of the pulpal lumen at the fracture site) and mobility of the coronal fragment, dislocation of the coronal fragment and diastasis between fragments (i.e. rupture or stretching of the pulp at the fracture site).