Periodontal healing after replantation and autotransplantation of incisors in monkeys

The effect of injury to the cemental or alveolar part of the periodontal ligament upon periodontal healing after replantation and autotransplantation of teeth was studied in green Vervet monkeys. Sixty-six maxillary central incisors were replanted or autotransplanted after extra-alveolar periods of 18 min. saline storage or 120 min. dry storage. The animals were sacrificed after 8 weeks and the teeth examined histometrically. Identical healing was found in the following experimental groups: replantation or autotransplantation after 18 min. and replantation with or without removal of periodontal ligament in the alveolus. A significant increase in replacement resorption (ankylosis) compared to the 18 min. replantation group was found in the following groups: replantation and autotransplantation after 120 min., replantation after removal of periodontal ligament on the root surface and autotransplantation after 120 min. to a socket where the tooth was extracted 18 min. earlier. Autotransplantation after 18 min. to a socket where a tooth had been extracted 120 min. earlier led to a significant increase in the amount of replacement resorption compared to transplantation to an 18 min. socket. Based on these findings, it is concluded that the presence of an intact and viable periodontal ligament on the root surface is the most important factor in assuring healing without root resorption. The length of the extra-alveolar period also seems to exert some influence upon the socket, enhancing the development of ankylosis.     

Effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation of mature permanent incisors in monkeys

The effect of extra-alveolar period and storage media upon periodontal and pulpal healing after replantation was studied in green Vervet monkeys (Cercopithecus aethiops). Mandibular lateral incisors were extracted. The extra-alveolar period before replantation was 0, 18, 30, 60, 90, and 120 min. The storage media for the extracted teeth were tap water, physiologic saline, saliva or dry storage. The animals were sacrificed 8 weeks after replantation and the replanted teeth were examined histometrically. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), periapical inflammatory changes, the extent of vital pulp and downgrowth of pocket epithelium. A significant relationship was found between the frequency of root resorption, extra-alveolar period and storage medium. This was especially evident after dry storage. Surface resorption was found with approximately the same frequency irrespective of extra-alveolar period and storage media. Inflammatory root resorption was especially common after dry storage and was related to the length of the extra-alveolar period. Already after 30 min dry storage, this resorption type was very prominent. Teeth stored in tap water, saline or saliva showed about the same frequency of inflammatory resorption, which increased slightly with increased extra-alveolar periods. Replacement resorption showed a strong relationship to dry storage and became very prominent after 60 min. Replacement resorption was rarely found among teeth stored in saline or saliva; whereas it was significantly increased among teeth stored in tap water. It is concluded that saline and saliva offer good protection against root resorption during the extra-alveolar period.     

The effect of extra-alveolar root filling with calcium hydroxide on periodontal healing after replantation of permanent incisors in monkeys

The effect of calcium hydroxide, used as an extra-alveolar root filling material, on periodontal healing was examined in green vervet monkeys (Cercopithecus aethiopa). Incisors were extracted and a root canal filling of calcium hydroxide paste was processed. Control teeth were replanted after either pulp extirpation or root filling with gutta-percha. In the experimental groups, the extra-alveolar period was either 18 or 120 minutes. The animals were killed eight weeks after replantation, and the replanted teeth were examined histologically. The histologic parameters recorded for each tooth were surface resorption, inflammatory resorption, replacement resorption (ankylosis), periapical inflammatory changes, and downgrowth of pocket epithelium. Teeth with canals filled with calcium hydroxide that had an extra-alveolar time period of 18 minutes, showed noticeably more replacement resorption than either the teeth with canals filled with gutta-percha or those with extirpated pulps. Calcium hydroxide paste may diffuse through the apical foramen, thus injuring the periodontal ligament in the apical region. Consequently, the use of calcium hydroxide does not seem justified in the initial treatment of avulsed teeth, but it can be used after some weeks when periodontal ligament healing has progressed.     

The effect of removal of the coagulum in the alveolus before replantation upon periodontal and pulpal healing of mature permanent incisors in monkeys

The effect of removal of the coagulum in the alveolus before replantation upon periodontal and pulpal healing was studied in green Vervet monkeys (Cercopithecus aethiops). Mandibular lateral incisors were extracted. The extra-alveolar period before replantation was 60 min. The storage medium for the extracted teeth was physiologic saline. On the right side of the mandible, the coagulum was removed before replantation, using syringe with saline assisted by a spoon-shaped excavator. On the left side, the tooth was replanted with the coagulum in situ. The replanted teeth were examined histologically after 8 weeks. The histometric analysis showed no significant difference in periodontal or pulpal healing between the two groups. Based on this finding, it is suggested that replantation of avulsed mature teeth be carried out immediately, without any attempt to remove the coagulum.     

Storage conditions of avulsed teeth affect the phenotype of cultured human periodontal ligament cells

After severe injury to the periodontal ligament (PL), the phenotypes of cells recolonizing root surfaces influence the extent and type of repair processes. In teeth that are replanted following avulsion injury, recolonization of the PL space by osteogenic cells instead of by PL fibroblasts may favor bone formation (i.e. ankylosis) instead of PL regeneration. We consider here that recolonization processes depend in part on the storage conditions of the teeth following avulsion. We used an in vitro cell culture model to assess the effect of storage conditions on immunohistochemical staining of several marker proteins that are expressed by osteogenic cells (osteopontin and alkaline phosphatase) and fibroblasts (alpha-smooth muscle actin, type III and XII collagens). Prior to cell culture, extracted human premolar teeth were stored in air ("dry") or in alpha-MEM ("wet") for either 30 or 120 min as surrogate conditions for the variations of extra-alveolar tooth storage that may occur following avulsion. Collagenase/trypsin-digested suspensions of PL cells were prepared from the tissue adherent to the extracted root surface. Passage #2 or #3 cultures were immunostained and examined by fluorescence microscopy. For type XII collagen, cells from wet samples displayed perinuclear staining while cells from 30-min dry samples showed only isolated foci. The staining for 120-min dry samples was weak and non-specific. alpha-Smooth muscle actin was not incorporated into stress fibers in wet samples, whereas dry samples demonstrated prominent stress fibers stained for alpha-smooth muscle actin. Detached cytoplasmic fragments resembling cell processes that stained for alpha-smooth muscle actin were abundant in dry samples, indicating the presence of highly contractile cells. The staining for osteopontin was mainly perinuclear but was more intense in dry samples. The focal adhesion pattern of osteopontin staining in 120-min dry samples resembled that of migrating osteogenic cells. The pattern of staining did not vary for type III collagen or alkaline phosphatase, although staining for alkaline phosphatase was more intense in samples stored under dry conditions. We conclude that prolonged extra-alveolar dry storage favors increased in vitro growth of contractile cells expressing osteogenic cell markers while storage in cell culture medium favors growth of cells with the classical phenotype of PL fibroblasts.     

Periodontal healing of replanted monkey teeth prevented from drying

Root resorption of replanted teeth is dependent on the duration of the extra-alveolar period and on the storage environment. In the present investigation the significance of preserving the humidity of the periodontal ligament (PDL) during the extra-alveolar period was tested on isolated PDL cells and on replanted monkey teeth. The isolated PDL cells were tested with respect to cell viability (trypan blue exclusion test) and to cell recovery (number of cells after additional cultivation). About 70% of the cells were viable and 44% recovered after 1 h in a humid atmosphere. Practically no cells were viable or recovered after 1 h of drying. Replanted teeth that had been wrapped in plastic foil for 1 h before replantation showed no more resorption than immediately replanted teeth. This is in contrast to teeth dried in air for 1 h before replantation. They showed extensive root resorption on almost all root surfaces. Thus, prevention of evaporation of tissue fluid from the PDL must be considered a primary goal if the tooth cannot be replanted immediately.     

Periapical tissue reactions to calcium hydroxide and MTA after external root resorption as a sequela of delayed tooth replantation

Clinical experience has shown that most avulsed teeth are replanted after a long extra-alveolar time and dry or inadequate wet storage, causing necrosis of periodontal ligament cells. This condition invariably leads to development of external root resorption, leaving the filling material in contact with the periapical connective tissues. In this study, the periapical tissue reactions to calcium hydroxide (CH) and mineral trioxide aggregate (MTA) were evaluated after occurrence of external root resorption as an expected sequela of delayed tooth replantation. Twenty male Wistar rats (Rattus norvegicus, albinus) had their right upper incisor extracted and maintained in dry storage for 60 min. Then, the dental papilla, enamel organ, pulp tissue, and periodontal ligament were removed, and the teeth were immersed in a 2% acidulated phosphate sodium fluoride solution, pH 5.5, for 10 min. The teeth were randomly assigned into two groups (n = 10), in which the canals were filled with either a CH and saline paste (CH group) or MTA (MTA group). The sockets were irrigated with saline, and the teeth were replanted. After 80 days, it was possible to observe large areas of replacement root resorption and some areas of inflammatory root resorption in both groups. More severe inflammatory tissue reaction was observed in contact with calcium hydroxide compared with the mineral trioxide aggregate. New bone formation was more intense at the bottom of the socket in the MTA group. In conclusion, as far as periapical tissue compatibility is concerned, intracanal MTA can be considered as a viable option for root canal filling in delayed tooth replantation, in which external root resorption is an expected sequela.     

Periodontal and pulpal healing of monkey incisors preserved in tissue culture before replantation.

The effect of delayed replantation and tissue culture as a prevention against root resorption was examined in green Vervet monkeys (Cercopithecus aethiops). Extracted incisors were kept in tissue culture medium (Eagle's medium) for 5--14 days before replantation. The extra-alveolar dry period before tissue culture ranged from to 0 to 60 min. Incisors not subjected to tissue culture served as controls. The animals were sacrificed 8 weeks after replantation. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), downgrowth of pocket epithelium, and periapical inflammatory changes. The evaluation of the pulp included the extent, recorded in mm, of pulp survival. Histometric evaluation showed that teeth immediately placed in tissue culture medium for 5--14 days showed improved periodontal healing, exhibiting significantly less inflammatory resorption than control teeth immediately replanted. Also the extent of pulp survival was significantly increased in teeth replanted after tissue culture. Teeth bench-dried for 60 min and thereafter placed in tissue culture medium also showed a significant reduction in the amount of inflammatory resorption and increased amount of pulp survival compared with control teeth replanted after the 60-min dry extra-alveolar period. Replacement resorption (ankylosis) was found in all teeth in both groups.     

Evaluation,using extracted human teeth,of Ricetral as a storage medium for avulsions – an in vitro study

Abstract – The prognosis of teeth replanted following avulsion is determined by the extra‐alveolar time and storage medium used. This study was undertaken to determine the efficacy of an oral rehydration solution ‘Ricetral’, in retaining the vitality of periodontal ligament cells when used as a storage medium for avulsed teeth prior to replantation. The study consisted of a comparative evaluation between Ricetral and two currently recommended solutions, Hank’s balanced salt solution (HBSS) and milk. Thirty extracted teeth were dried for 30 min and soaked in the respective storage media for 45 min. The periodontal ligament cells were isolated by an enzyme treatment with collagenase and trypsin. The cells were evaluated for vitality by trypan blue staining and number of vital cells counted in a hemocytometer. Statistical analysis revealed that cell vitality was high with Ricetral and HBSS, but poor with milk.     

The effect of saline storage before replantation upon dry damage of the periodontal ligament

Abstract The effect of 30 min of saline storage before replantation of teeth, which had been dried out for 30 min, was studied in 10 Green Vervet monkeys (Cercopithecus aethiops). Maxillary central incisors were extracted and dried out for 30 min, after which 1 incisor was replanted and the other transferred to a saline solution for 30 min before replantation. No splinting or endodontic treatment was carried out. The teeth were examined after 8 wk. Histometric analysis showed identical extent of root resorption in the 2 groups, with ankylosis being the dominant resorption type, and with very limited pulpal repair in either group. It is concluded that saline storage under the experimental conditions chosen had no effect on development of root resorption or pulpal repair, presumably because 30 min dry storage had inflicted close to maximal damage on the periodontal ligament at the root surface. On the other hand, it is of clinical importance that a certain delay in the replantation procedure does not influence periodontal and pulpal healing, as long as the tooth is kept in saline storage. This suggests that replantation under these conditions can be reserved for dental professionals, rather than favoring immediate replantation by anyone ‘on-the-spot’.     

Repair processes in the cervical region of replanted and transplanted teeth in monkeys

The repair processes in the cervical region of replanted teeth where the periodontal ligament was injured by either extensive drying or removal was studied. These repair processes were related to various clinical factors, such as splinting, traumatic occlusion and exactness of repositioning. Permanent incisors were extracted, root filled extraorally and allotted to the following experimental groups: (1) PDL injured by drying, no splinting; (2) PDL injured by drying, splinting for 2 weeks; (3) PDL injured by drying, replanted tooth in traumatic occlusion; (4) PDL injured by drying, no splinting, non-exact repositioning of the replanted tooth; (5) PDL removed, no splinting. The animals were sacrificed 8 weeks after replantation and the replanted teeth examined histometrically. The different groups demonstrated area with normal periodontal ligament extending from 0.4 to 1 mm apically from the crestal margin, where the greatest extent was found in teeth with non-exact repositioning. The possible role of the gingiva in these repair processes is discussed.     

Dynamics of dentoalveolar ankylosis and associated root resorption

Abstract The present experimental studies in monkeys were undertaken to study the initiation and progression of dentoalveolar ankylosis of replanted teeth and associated root resorption. Maxillary and mandibular lateral incisors were extracted and replanted after an extraoral period of 15 min or 1 h. Teeth with an extraoral period of 1 h were endodontically treated. Half the number of monkeys were given antibiotics at the time of replantation. The observation periods varied from 2 days to 40 weeks. Irrespective of the length of the extraoral period, initial root resorption and minor areas of ankylosis were found 1 week after replantation. The initial ankylosis was not preceded by root resorption. In teeth replanted after an extraoral period of 15 min the ankylotic area did not increase with increasing time after replantation. Instead the periodontal membrane was re-established, separating the root surface from the alveolar bone. In teeth replanted after an extraoral period of 1 h, the initial ankylotic area increased with increasing time after replantation. Eight weeks and more after replantation, most of the periodontal membrane was replaced by bone covered by osteoblasts and occasional osteoblasts that were in continuity with the endosteal cells outlining the marrow spaces of the alveolar bone. The cementum and dentin were then gradually resorbed with increasing time after replantation. Antibiotics given at the time of replantation reduced the initial inflammation in the periodontal membrane and the inflammatory root resorption after all observation periods and it also seemed to some extent to prevent bacteria from entering the necrotic pulp tissue. Based on the present results it is suggested that root resorption associated with dentoalveolar ankylosis is initiated by endosteal osteoblasts and is thus a hormonally regulated process. This is in contrast to inflammatory root resorption, which seems to be triggered by inflammatory cells.     

Dynamics of dentoalveolar ankylosis and associated root resorption

The present experimental studies in monkeys were undertaken to study the initiation and progression of dentoalveolar ankylosis of replanted teeth and associated root resorption. Maxillary and mandibular lateral incisors were extracted and replanted after an extraoral period of 15 min or 1 h. Teeth with an extraoral period of 1 h were endodontically treated. Half the number of monkeys were given antibiotics at the time of replantation. The observation periods varied from 2 days to 40 weeks. Irrespective of the length of the extraoral period, initial root resorption and minor areas of ankylosis were found 1 week after replantation. The initial ankylosis was not preceded by root resorption. In teeth replanted after an extraoral period of 15 min the ankylotic area did not increase with increasing time after replantation. Instead the periodontal membrane was re-established, separating the root surface from the alveolar bone. In teeth replanted after an extraoral period of 1 h, the initial ankylotic area increased with increasing time after replantation. Eight weeks and more after replantation, most of the periodontal membrane was replaced by bone covered by osteoblasts and occasional osteoblasts that were in continuity with the endosteal cells outlining the marrow spaces of the alveolar bone. The cementum and dentin were then gradually resorbed with increasing time after replantation. Antibiotics given at the time of replantation reduced the initial inflammation in the periodontal membrane and the inflammatory root resorption after all observation periods and it also seemed to some extent to prevent bacteria from entering the necrotic pulp tissue. Based on the present results it is suggested that root resorption associated with dentoalveolar ankylosis is initiated by endosteal osteoblasts and is thus a hormonally regulated process. This is in contrast to inflammatory root resorption, which seems to be triggered by inflammatory cells.     

Experimental study of periodontal tissue regeneration. Changes in the periodontium after tooth implantation with and without periodontal ligament

The role of the periodontal ligament in periodontal tissue regeneration was evaluated. The materials included bilateral upper 1st premolars and lower 2nd, 3rd, and 4th premolars of 11 adult Beagle dogs, aged from 3 to 6 years. Before implantation, the right teeth were extracted and kept for a period of more than 3 months in "a solution for reserving teeth". The left teeth on the other hand, were extracted and soon implanted thus retaining the periodontal ligament into the newly created bone cavities prepared in the right edentulous areas. At the same time, the right reserved teeth were implanted into the left tooth sockets. Implanted teeth were periodically observed macroscopically, radiographically, and histologically for a 6-month period. Macroscopical observation showed good clinical repair in the bilateral sides of the tooth implantation with and without a periodontal ligament. After a 6-week experimental period, radiographic observations of the implanted lower right teeth having a periodontal ligament revealed lamina dura-like findings. Histopathological investigation revealed ankylosis and root resorption on the left side, where the reserved teeth without a periodontal ligament were implanted. But regeneration of the periodontal tissue complex, which consisted of the gingiva, alveolar bone, cementum, and periodontal ligament, was generally observed in the implanted right teeth having a periodontal ligament. These results suggest that the periodontal ligament cells play a significant role in periodontal tissue regeneration.     

A quantitative analysis of Propolis: a promising new storage media following avulsion

Abstract –  Both length of extra-alveolar time and type of storage media are significant factors that can affect the long-term prognosis of replanted teeth. Numerous studies have examined various media in an attempt to determine the ideal material for storage of the avulsed tooth. The purpose of this study was to use a Collagenase–Dispase assay to investigate the potential of a new storage media, Propolis, in maintaining viable periodontal ligament (PDL) cells on simulated avulsed teeth. Seventy freshly extracted human teeth were divided into five experimental groups and two control groups. The positive and negative controls corresponded to 0-min and an 8-h dry time, respectively. The experimental teeth were stored dry for 30 min and then immersed in one of the five media (Hank's balanced salt solution (HBSS), milk, saline, Propolis 50%, and Propolis 100% for 45 min). The teeth were then treated with dispase grade II and collagenase for 30 min. The number of viable PDL cells were counted with a hemocytometer and analyzed. Statistical analysis demonstrated that both Propolis groups kept significantly more PDL cells viable compared to either milk, saline, or HBSS. Within the parameters of this study, it appears that Propolis may be a better alternative to HBSS, milk, or saline in terms of maintaining PDL cell viability after avulsion and storage.     

Replantation of 400 avulsed permanent incisors. 3. Factors related to root growth

Abstract Four hundred avulsed and replanted permanent incisors were examined for pulpal and periodontal healing. In 30 teeth, root formation was incomplete at the time of injury. Two teeth were excluded from the study due to nonphysiological extraalveolar storage (i.e. homemade saline). Of the 28 remaining replanted incisors, 7 showed subsequently completed root development, 8 partially completed root development and 13 arrested root development. Completed root development subsequent to replantation was found to be significantly related to pulpal revascularization, being rare in cases with pulp necrosis (5 of 15 teeth) and frequent after pulpal healing (11 of 13 teeth) (p=0.01). Root development was not found to be significantly related to the extraalveolar storage period; but occurred slightly more frequently when the dry–storage period was less than 45 min. (p=0.13). Ingrowth of bone and formation of an internal periodontal ligament (PDL) was found in 6 teeth and was related to arrested root formation in cases with pulpal healing. The explanatory factor for these findings appeared to be damage to the Hertwig's epithelial root sheath.     

Effects of temperature, storage time and media on periodontal and pulpal healing after replantation of incisors in monkeys

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.     

Replantation of avulsed teeth after long extra-alveolar periods

In 11 patients, 18 teeth, with extra-alveolar periods ranging from 6 h to 48 days were replanted after root-filling with chloroform resin and guttapercha. After observation periods from 1 to 7 years, only 1 tooth was lost (after 5 years), but the remaining 17 teeth were clinically well functioning. All teeth were ankylotic and subjected to replacement resorption of various extent. Inflammatory root resorption and periradicular osteitis were not observed. Marginal bone loss up to 5 mm was noticed, but was accompanied by gingival retraction and thus pathological periodontal pockets (5 mm) were not observed. Consequently, teeth replanted after long extra-alveolar periods (even several days) can function for many years and thus postpone prosthetic treatment.     

The effect of citric acid treatment on periodontal healing after replantation of permanent teeth

The aim of this study was to evaluate the effect of surface demineralization on the healing of 120 replanted teeth in fifteen 8- to 16-month-old dogs. Replanted teeth were divided into two groups (A and B). In group A, teeth were replanted following planing of the entire root surface. In group B, teeth were replanted following planing and surface demineralization with citric acid. Replanted teeth were splinted for 7 days, and observation periods were 3, 14 and 56 days. A total of 95 teeth and their surrounding tissues were examined histologically under a light microscope. Histological examination of specimens 3 days after replantation revealed that initial reunion between the root and the alveolar periodontal ligament fibres was via a fibrin-like network in both groups. Fourteen days after replantation histological observations showed superior healing in group B with regard to epithelial condition, periodontal ligament fibre reattachment to the root surface, resorption and functional arrangement of the periodontal ligament fibres. By 56 days after replantation, healing was superior in group A; group B was characterized by severe inflammatory and replacement resorption. These results indicated that surface demineralization had an initial positive effect, but later led to impaired healing.     

Evaluating Emdogain® and healing of replanted teeth using an intra-individual experimental–control study design

Abstract –  The purpose of the present investigation was to use an intra-individual experimental–control study design to explore if application of Emdogain^® prior to re-plantation after a dry extra-alveolar period of 60 min would promote a favorable healing of the periodontal ligament cells. Ten patients, for whom already decisions had been taken to extract two maxillary premolars because of crowding, participated in the study. The teeth were extracted and endodontic treatment was performed extra orally. The experimental tooth and its alveolar socket were covered with Emdogain^® prior to replantation. The contra lateral tooth served as a control and was replanted without any prior treatment. The teeth were stabilized with a retainer for 3–7 days and the patients were followed up every third week. After 13 weeks, the teeth were finally extracted and prepared for histological examination. Radiographs were taken before the study period, at day 29 and prior to the final extraction. The results were in favor of Emdogain^®, but the overall difference between the Emdogain^®-treated tooth and its control was rather small, and it seemed questionable if the registered differences could be of any obvious practical clinical importance. Histologically, all the teeth showed some degree of pathology after such a long dry extra-oral time and the outcome seemed to be more correlated to the individual than to the treatment. Given more favorable conditions regarding storage medium and/or extra-oral time, Emdogain^® might still be of value for an uncomplicated healing after replantation.