Effect of Early Orthodontic Force on Periodontal Healing After Autotransplantation of Permanent Incisors in Beagle Dogs

An evaluation of 1654 premolars transplanted in the posterior region-A retrospective analysis of survival, success and complications

AIM

The aim of this retrospective analysis was to evaluate the survival, success and possible complications of transplanted premolars in the posterior region subdivided by developmental stage and patient age.

MATERIALS AND METHODS

This study included patients who underwent tooth transplantation between April 2004 and December 2021. A total of 1654 premolars were transplanted into 1243 patients. Tooth mobility, oral hygiene and periodontal parameters were clinically evaluated. Intraoral radiographs were used to evaluate pulpal and periodontal healing, and root formation. The cumulative survival rate was calculated using the Kaplan-Meier method.

RESULTS

Data were subdivided into three groups based on the stage of root development and patient age. The mean age at surgery was 14.5 years. The main indication for transplantation was agenesis, followed by trauma and other indications, such as impacted or malformed teeth. A total of 11 premolars were lost during the study period. The overall survival and success rates in the immature premolar group after an observation period of 10 years were 99.7% and 99.4%, respectively. High survival and success rates (95.7% and 95.5%, respectively) were also observed when fully developed premolars were transplanted into the posterior region of adolescents. In adults, the success rate after 10-year follow-up is 83.3%.

CONCLUSIONS

Transplantation of premolars with developing and fully developed roots is a predictable treatment modality.

Treatment of an Avulsed and Ankylosed Incisor through Single Tooth Alveolar Osteotomy and Conventional Orthodontic Mechanisms

We present the treatment of an injured and avulsed incisor (which was afterwards ankylosed), by subapical osteotomy and conventional orthodontic mechanisms. A 9-year-old boy presented for orthodontic treatment with an injured and avulsed central incisor, which, after initial repositioning, ended up with ankylosis and severe root resorption. The case was treated by single tooth alveolar osteotomy and distraction osteogenesis through conventional orthodontics, advocating for the floating bone concept due to the short vertical distance by which the tooth alveolus part had to be relocated. Orthodontic treatment of the avulsed central incisor was completed after osteotomy and distraction osteogenesis, and the tooth was restored to its proper position, aiming to address issues of aesthetics and function for the time being. The patient was finally referred to a prosthodontist for future and final implant rehabilitation due to severe root resorption. Distraction osteogenesis after surgical procedures is a reliable solution for dealing with an ankylosed and submerged tooth.

The Effect of Mechanical Vibration on Osteogenesis of Periodontal Ligament Stem Cells

INTRODUCTION

Appropriate occlusal forces can prevent ankylosis after tooth replantation or transplantation. However, the "proper occlusal forces" on periodontal ligament (PDL) healing have not yet been defined due to insufficient in vitro studies and uncertain in vitro models. Herein, we presented a mechanical vibration device as an in vitro model to determine such favorable occlusal forces.

METHODS

Human periodontal ligament stem cells (hPDLSCs) were exposed to mechanical vibration force with 4 frequencies (30, 90, 150, and 210 rpm). Cell viability and the expression of osteogenic differentiation-related genes and proteins were tested in vitro. The calvarial transplantation experiment was performed to assess the bone formation ability of 150 rpm mechanical vibration stimulation (MVS).

RESULTS

MVS at 150 and 210 rpm significantly reduced cell viability in the early stages. The 150-rpm MVS decreased osteogenic marker expression at the early time point (3 days) but had no harmful effects at the late time point (14 days). Furthermore, hPDLSC cell sheets treated with 150-rpm MVS had potential to decrease bone formation in rat calvarial defects serendipitously and facilitated functional PDL-like tissue formation.

CONCLUSIONS

We found that MVS at a frequency of 150 rpm could provide a strategy for a transient reduction in the osteogenic potential of hPDLSCs and promote PDL-like tissue formation. Thus, 150-rpm MVS could be used as a controllable proper occlusal force to prevent ankylosis and promote PDL healing after tooth replantation or transplantation.

Periodontal ligament repair after active splinting of replanted dogs' teeth

BACKGROUND/AIM

The high rate of root resorption resulting from tooth replantation represents a serious clinical problem. In order to prevent ankylosis and replacement resorption, the contemporary literature highlights the importance of using a flexible stabilization for traumatized teeth. For this purpose, orthodontic devices may be promising for obtaining a better prognosis and periodontal repair. The aim of this study was to evaluate the effect of an active splinting protocol with controlled force in dog's teeth following replantation.

MATERIAL AND METHODS

Sixty premolar roots from three dogs were used. They were submitted to endodontic treatment, hemisected, atraumatically extracted and subsequently replanted. They were divided into four groups: Passive Stabilization (n = 20)-after 20 min in a dry medium; Active Stabilization (n = 20)-after 20 min in a dry medium; Negative control (n = 10)-immediate replantation and passive Stabilization; and Positive control (n = 10)-90 min of extra-alveolar time and passive Stabilization. The samples were collected and submitted to histologic processing. They were then evaluated for the count of inflammatory cells, expression of neurotrophin 4, osteoclasts, apoptotic cells and collagen fibres. The results were submitted to ANOVA or Kruskal-Wallis statistical tests followed by Tukey or Dunn post-tests (α = 5%).

RESULTS

Passive Stabilization with orthodontic brackets without traction used after replantation had the highest number of inflammatory cells (p = .0122), osteoclasts (p = .0013) and percentage of collagen fibres in the periodontal ligament (p < .0001) when compared to Active Stabilization with orthodontic brackets applying amild tensile force. Neurotrophin 4 had no statistically significant difference (p = .05), regardless of the treatment. The apoptotic cells count revealed statistical differences (p < .0001) between Active Stabilization (189.70 ± 47.99) and Positive Control (198.90 ± 88.92) when compared to Passive Stabilization (21.19 ± 32.94).

CONCLUSION

The active splinting protocol using orthodontic appliances generating a light and controlled force favoured periodontal ligament repair of replanted teeth.

A conservative approach for an adult patient with a fractured tooth and crowding: Autotransplantation at the fracture site

Autotransplantation of a mature premolar in adults can be a treatment of choice for tooth replacement when combined with well-planned orthodontic treatment. This case report describes the successful treatment of a 39-year-old patient with severe crowding and a hopelessly fractured tooth on the maxillary left side. Maxillary dental crowding was relieved by extraction of a premolar on the right side, and this extracted tooth was autotransplanted to replace the fractured tooth. A mandibular incisor was extracted to correct anterior crossbite. The total treatment period was 20 months. The treatment results showed a good long-term prognosis after transplantation of a mature premolar with normal surrounding alveolar bone level for over 6 years of follow-up. Occlusion and periodontal health were excellent in the long term.

Successful pulp revascularization of an autotransplantated mature premolar with fragile fracture apicoectomy and plasma rich in growth factors: a 3-year follow-up

AIM

This case report demonstrates a positive outcome of the adjuvant use of fragile fracture (FF), which is a technique used to harvest dental pulp stem cells (DPSCs), and platelet-rich plasma (PRP) in a mandibular premolar (tooth 44) with a completely formed root that was transplanted into a surgically created socket and which maintained pulp vitality and function.

SUMMARY

After virtual surgical planning, a 3D tooth replica of tooth 44 was fabricated. A surgical socket was created in the position of tooth 14; then, tooth 44 was extracted and the root dentine was abraded using a turbine diamond bur 3 mm from the apex until a circular groove was prepared around the outer circumference of the root; and then, an FF was performed without damaging the pulp tissue. PRP was placed in the socket, after which the donor tooth was inserted in the recipient area. At 2 weeks post-treatment, orthodontic traction was applied. At 3-year follow-up, the tooth had adequate alignment and was asymptomatic. Response to pulp testing was positive, and the presence of pulp canal obliteration was observed as a sign of pulpal healing.

KEY LEARNING POINTS

Autotransplantation is a good alternative for replacing missing teeth, with repair of tissues and pulp revascularization. Revascularization of an autotransplanted mature tooth using the fragile fracture technique and PRP scaffold is a feasible option and might have positive effects on the long-term outcome of the procedure. Including completely formed teeth as donors in autotransplantation, maintaining vitality and their functions is an option that warrants further study.

Alternative treatment plan for congenitally missing teeth in an adolescent patient: A case report

BACKGROUND AND OVERVIEW

Mandibular second premolars are the second most commonly missing teeth, and there are various treatment alternatives to restore the space of the missing teeth. However, in growing patients, implants are contraindicated because they prevent growth of bone.

CASE DESCRIPTION

In this case report, the authors describe a 13-year-old girl with Class II malocclusion with congenitally missing mandibular second premolars. Autotransplantation of 2 maxillary premolars to the missing teeth site was performed considering the presence of crowding in the maxillary anterior segment. The teeth were fixed with a semirigid splint for 3 months. The patient had an acceptable occlusion at the end of the orthodontic treatment, which lasted 20 months.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The autotransplanted right premolar showed normal physiological adaptation, whereas the tooth on the left side was ankylosed. The short-term results show that autotransplantation, which requires high technical sensitivity, may provide a biological and economical alternative to tooth replacement.

Effect of fibroblast growth factor on injured periodontal ligament and cementum after tooth replantation in dogs

PURPOSE

The purpose of this animal study was to perform a histological and histomorphometric analysis in order to elucidate the effect of fibroblast growth factor-2 (FGF-2) on injured periodontal ligament (PDL) and cementum after tooth replantation in dogs.

METHODS

The roots of 36 mandibular premolars from six mongrel dogs were used in this study. The roots were randomly divided into three groups: (1) a positive control group (n=12), in which the PDL was retained; (2) a negative control group (n=12), in which the PDL and the cementum between the notches were removed; and (3) an experimental group (n=12), in which the PDL and the cementum between the notches were removed and the roots were soaked in an FGF-2 solution (30 µg/0.1 mL). After treating the root surfaces, the extracted roots were replanted into extraction sockets. The animals were sacrificed four and eight weeks after surgery for histologic and histomorphometric evaluation.

RESULTS

At four and eight weeks, normal PDLs covered the roots in the positive control group. In the negative control group, most replanted roots showed signs of replacement resorption. In the experimental group, new PDL-like tissue and cementum-like tissue were observed to partially occupy the region between the root surfaces and the newly formed bone. Histomorphometric analysis showed that the mean length of the newly formed cementum-like tissue on the roots treated with FGF-2 was significantly greater than that of the tissue on the roots in the negative control group (four weeks, P=0.008; eight weeks, P=0.042). However, no significant differences were observed between the roots treated with FGF-2 and the negative control roots with respect to newly formed PDL-like tissue.

CONCLUSIONS

The results of this study suggest that use of FGF-2 on injured root surfaces promotes cementogenesis after tooth replacement in dogs.

Autotransplantation combined with orthodontic treatment: a case involving the maxillary central incisors with root resorption after traumatic injury

Traumatic dental injury can result in avulsion of anterior teeth. In young patients, it is a challenge to the dental professional because after replantation, late complications such as ankylosis require tooth extraction. Although prosthetic and orthodontic treatment, and implant placement have been described as the options for intervention, autogenous tooth transplantation could be an effective procedure in growing patients if there is a suitable donor tooth available. This case presents the treatment of a patient who suffered a traumatic injury at 9 years old with avulsion of tooth 21, which had been replanted, and intrusion of tooth 11. Both teeth ankylosed; thus they were removed and autotransplantation of premolars was carried out. After transplantation, the tooth underwent root canal treatment because of pulpal necrosis. Orthodontic treatment began 3 months after transplantation and during 7 years' follow-up the aesthetics and function were maintained without signs of resorption.