ARTICLE IN PRESS
YBJOM-4487; No. of Pages 3
Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
Short communication
Insertion torque of dental implants after microvascular fibular grafting P.S.Z. Maluf ∗ , A.W. Ching, P. Angeletti, J.L.G. Bretos, L.M. Ferreira Division of Plastic Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil Accepted 30 March 2015
Abstract We have measured the necessary torque to the initial stabilisation of dental implants in revascularised bony transplants for reconstruction of the maxilla and mandible in edentulous patients. We installed 28 dental implants in 7 patients who had had reconstructions of the maxilla and mandible by microsurgical flaps. At the time of the installation of the implants, we measured the torque for final stabilisation. The minimum torque was 20 Newton centimetres (N cm) in 11 implants, and the maximum 45 N cm in 8. The measure of torque was not influenced by sex, age group, or time between transplant and implant. © 2015 Published by Elsevier Ltd. on behalf of The British Association of Oral and Maxillofacial Surgeons.
Keywords: Dental implantation; Tissue transplantation; Endosseous; Fibular free flaps; Torque
Introduction Microvascular bone transfer is the best technique for mandibular and maxillary reconstruction. The fibula is the donor site of choice in most cases, and gives good functional and aesthetic results.1 Jaquiéry et al.2 studied 8 patients who were treated with microvascular bony transfer and immediate placement of implants. Only 2/29 implants failed because of avascular bone at the distal end of the graft, and were removed.2 The measurement of the insertion torque is important for predicting the prognosis of integration between implants and host bones.3 Instability of the implant cylinder during placement may lead to micromotion of the implant, which reduces the possibility of osseointegration.4 On the other hand, excessive insertion torque may result in ischaemia and necrosis ∗ Corresponding author at: Division of Plastic Surgery, Rua Napoleão de Barros 715, 4o. andar, CEP 04042-002 São Paulo, SP, Brazil. Tel.: +55 11 5576 4118; fax: +55 11 5576 4118. E-mail address: [email protected] (P.S.Z. Maluf).
of the bone around the implant.5 Manual torque wrenches are commonly used for better control and precision of the insertion torque during the tightening of implants.6 An insertion torque of 5 N cm has been considered as the minimum torque necessary for the stability of an implant, and 50 N cm as the maximum torque to prevent pressure necrosis around the implant cylinder, which results in better osseointegration.7
Patients and methods We studied patients aged 18 years or over, who had had mandibular and maxillary bone reconstruction by microvascular fibular grafting with autogenous bone, with grafts 100 mm or more long, showing a well-incorporated bone graft for more than one year, with available bone height of 10 mm or more and width 5 mm or more. Cylinder external hex titanium implants (Serson Implant, São Paulo, Brazil), 3.75 mm in diameter and 10 mm long, with a platform-abutment connection 4.1 mm in diameter,
http://dx.doi.org/10.1016/j.bjoms.2015.03.016 0266-4356/© 2015 Published by Elsevier Ltd. on behalf of The British Association of Oral and Maxillofacial Surgeons.
Please cite this article in press as: Maluf PSZ, et al. Insertion torque of dental implants after microvascular fibular grafting. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.03.016
YBJOM-4487; No. of Pages 3
2
ARTICLE IN PRESS P.S.Z. Maluf et al. / British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
Fig. 1. The manual torque wrench used in the study.
and hexagonal width of 2.7 mm were used. Manual torque wrenches (Serson Implant, São Paulo, Brazil) were used to measure insertion torque (Fig. 1). Insertion of implants We followed the recommendations of Brånemark et al.5 The implants were placed with the patient under general anaesthesia and nasotracheal intubation. An incision was made on top of the alveolar crest at the grafted site. Four sites (I to IV) between teeth 43 and 33 were defined for the placement of the implants according to the dental prostheses to be installed in each patient. Perforations were spaced 4 mm apart (Fig. 2), and made using a spear-point and 2.0 mm, pilot 2/3, 3 mm, and counter-sink drills under external irrigation with 0.9% saline. The counter-angle head was positioned at right angles to the surface during the drilling of the implant site to ensure
Fig. 3. Orthopantomographic frontal view at the end of the distraction phase showing the four sites selected for placement, and the distance between implants.
proper orientation of the implant. All implants were inserted manually with torque wrenches. The implants and insertion instruments were made by the same manufacturer (Serson Implant, São Paulo, Brazil). The insertion torque was measured at the moment the implant head reached the alveolar crest. Insertion was completed using a second torque wrench, and the measurement of insertion torque was repeated and compared with the first measurement. The driver mount was then removed and replaced with the implant cover screw for sealing. The mucosal tissue was sutured with 4/0 polyglactin 910 sutures (Vicryl, Johnson & Johnson, São José dos Campos, Brazil). Insertion torque Four months after placement radiographs were taken, and the implants were exposed during the second-stage operation, which was done by the same surgeon using the same instruments. Osseointegration was tested by applying a torque of 10 N cm to evaluate mobility of the implant. If there was none, the patient was referred to the prosthetic treatment (Fig. 3).
Results Seven patients had implants placed to support dental prostheses. There were four men and three women, mean (SD) age 53 (14) years. A total of 28 implants were inserted into the grafted bones, 24 in the mandible and 4 in the maxilla. Only two of the 28 implants inserted were lost, the success rate being 26/28. The minimum insertion torque across the four implant sites was 20 N cm and the maximum 45 N cm.
Discussion Fig. 2. Diagram of the four sites selected for placement of implants, and distance between implants.
The establishment of the torque for the initial stability of the implant was a major concern because atrophy as a result
Please cite this article in press as: Maluf PSZ, et al. Insertion torque of dental implants after microvascular fibular grafting. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.03.016
YBJOM-4487; No. of Pages 3
ARTICLE IN PRESS P.S.Z. Maluf et al. / British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
of lack of function is a serious problem for maintenance of bone mass and bony remodelling. The use of manual torque wrenches is a simple, accessible way of measuring torque during placement and to control the torque applied to the bone-implant interface, which may prevent overload of the implant. There is a considerable risk of overloading the implant with an electric motor, which stops only when a preset torque is reached. The main criteria for successful osseointegration are no mobility of the implant and no pain when the implant functions.3 The insertion torque ranged from 20 N cm to 45 N cm, and the two that were lost with insertion torques of 20 N cm developed mobility and loss of bone 4 months after placement, which is consistent with reported results.5 Implants with a low insertion torque of 20 N cm were mostly placed in site II, which is the site associated with a more pronounced curvature of the grafted bone used in facial reconstruction. This result confirms the findings of Jaquiéry et al.,2 who reported a comparable success rate and a similar loss of implants, probably associated with insufficient blood supply and low bone density at the recipient site. Further studies are necessary to evaluate the characteristics of the prostheses used in patients who had undergone bony reconstructions, including considerations of problems with oral hygiene and occlusal maintenance.
3
Conflict of interest We have no conflict of interest. Ethics statement/confirmation of patients’ permission The study was approved by the Research Ethics Committee. References 1. Disa JJ, Cordeiro PG. Mandible reconstruction with microvascular surgery. Semin Surg Oncol 2000;19:226–34. 2. Jaquiéry C, Rohner D, Kunz C, et al. Reconstruction of maxillary and mandibular defects using prefabricated microvascular fibular grafts and osseointegrated dental implants – a prospective study. Clin Oral Implants Res 2004;15:598–606. 3. Ottoni JM, Oliveira ZF, Mansini R, et al. Correlation between placement torque and survival of single-tooth implants. Int J Oral Maxillofac Implants 2005;20:769–76. 4. Albrektsson T, Zarb G, Worthington P, et al. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11–25. 5. Brånemark PI, Zarb GA, Albrektsson T, editors. Tissue-integrated prostheses: osseointegration in clinical dentistry. Chicago: Quintessence; 1985. 6. Goheen KL, Vermilyea SG, Vossoughi J, et al. Torque generated by handheld screwdrivers and mechanical torquing devices for osseointegrated implants. Int J Oral Maxillofac Implants 1994;9:149–55. 7. Rabel A, Köhler SG, Schmidt-Westhausen AM. Clinical study on the primary stability of two dental implant systems with resonance frequency analysis. Clin Oral Investig 2007;11:257–65.
Please cite this article in press as: Maluf PSZ, et al. Insertion torque of dental implants after microvascular fibular grafting. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.03.016
YBJOM-4487; No. of Pages 3
Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
Short communication
Insertion torque of dental implants after microvascular fibular grafting P.S.Z. Maluf ∗ , A.W. Ching, P. Angeletti, J.L.G. Bretos, L.M. Ferreira Division of Plastic Surgery, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil Accepted 30 March 2015
Abstract We have measured the necessary torque to the initial stabilisation of dental implants in revascularised bony transplants for reconstruction of the maxilla and mandible in edentulous patients. We installed 28 dental implants in 7 patients who had had reconstructions of the maxilla and mandible by microsurgical flaps. At the time of the installation of the implants, we measured the torque for final stabilisation. The minimum torque was 20 Newton centimetres (N cm) in 11 implants, and the maximum 45 N cm in 8. The measure of torque was not influenced by sex, age group, or time between transplant and implant. © 2015 Published by Elsevier Ltd. on behalf of The British Association of Oral and Maxillofacial Surgeons.
Keywords: Dental implantation; Tissue transplantation; Endosseous; Fibular free flaps; Torque
Introduction Microvascular bone transfer is the best technique for mandibular and maxillary reconstruction. The fibula is the donor site of choice in most cases, and gives good functional and aesthetic results.1 Jaquiéry et al.2 studied 8 patients who were treated with microvascular bony transfer and immediate placement of implants. Only 2/29 implants failed because of avascular bone at the distal end of the graft, and were removed.2 The measurement of the insertion torque is important for predicting the prognosis of integration between implants and host bones.3 Instability of the implant cylinder during placement may lead to micromotion of the implant, which reduces the possibility of osseointegration.4 On the other hand, excessive insertion torque may result in ischaemia and necrosis ∗ Corresponding author at: Division of Plastic Surgery, Rua Napoleão de Barros 715, 4o. andar, CEP 04042-002 São Paulo, SP, Brazil. Tel.: +55 11 5576 4118; fax: +55 11 5576 4118. E-mail address: [email protected] (P.S.Z. Maluf).
of the bone around the implant.5 Manual torque wrenches are commonly used for better control and precision of the insertion torque during the tightening of implants.6 An insertion torque of 5 N cm has been considered as the minimum torque necessary for the stability of an implant, and 50 N cm as the maximum torque to prevent pressure necrosis around the implant cylinder, which results in better osseointegration.7
Patients and methods We studied patients aged 18 years or over, who had had mandibular and maxillary bone reconstruction by microvascular fibular grafting with autogenous bone, with grafts 100 mm or more long, showing a well-incorporated bone graft for more than one year, with available bone height of 10 mm or more and width 5 mm or more. Cylinder external hex titanium implants (Serson Implant, São Paulo, Brazil), 3.75 mm in diameter and 10 mm long, with a platform-abutment connection 4.1 mm in diameter,
http://dx.doi.org/10.1016/j.bjoms.2015.03.016 0266-4356/© 2015 Published by Elsevier Ltd. on behalf of The British Association of Oral and Maxillofacial Surgeons.
Please cite this article in press as: Maluf PSZ, et al. Insertion torque of dental implants after microvascular fibular grafting. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.03.016
YBJOM-4487; No. of Pages 3
2
ARTICLE IN PRESS P.S.Z. Maluf et al. / British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
Fig. 1. The manual torque wrench used in the study.
and hexagonal width of 2.7 mm were used. Manual torque wrenches (Serson Implant, São Paulo, Brazil) were used to measure insertion torque (Fig. 1). Insertion of implants We followed the recommendations of Brånemark et al.5 The implants were placed with the patient under general anaesthesia and nasotracheal intubation. An incision was made on top of the alveolar crest at the grafted site. Four sites (I to IV) between teeth 43 and 33 were defined for the placement of the implants according to the dental prostheses to be installed in each patient. Perforations were spaced 4 mm apart (Fig. 2), and made using a spear-point and 2.0 mm, pilot 2/3, 3 mm, and counter-sink drills under external irrigation with 0.9% saline. The counter-angle head was positioned at right angles to the surface during the drilling of the implant site to ensure
Fig. 3. Orthopantomographic frontal view at the end of the distraction phase showing the four sites selected for placement, and the distance between implants.
proper orientation of the implant. All implants were inserted manually with torque wrenches. The implants and insertion instruments were made by the same manufacturer (Serson Implant, São Paulo, Brazil). The insertion torque was measured at the moment the implant head reached the alveolar crest. Insertion was completed using a second torque wrench, and the measurement of insertion torque was repeated and compared with the first measurement. The driver mount was then removed and replaced with the implant cover screw for sealing. The mucosal tissue was sutured with 4/0 polyglactin 910 sutures (Vicryl, Johnson & Johnson, São José dos Campos, Brazil). Insertion torque Four months after placement radiographs were taken, and the implants were exposed during the second-stage operation, which was done by the same surgeon using the same instruments. Osseointegration was tested by applying a torque of 10 N cm to evaluate mobility of the implant. If there was none, the patient was referred to the prosthetic treatment (Fig. 3).
Results Seven patients had implants placed to support dental prostheses. There were four men and three women, mean (SD) age 53 (14) years. A total of 28 implants were inserted into the grafted bones, 24 in the mandible and 4 in the maxilla. Only two of the 28 implants inserted were lost, the success rate being 26/28. The minimum insertion torque across the four implant sites was 20 N cm and the maximum 45 N cm.
Discussion Fig. 2. Diagram of the four sites selected for placement of implants, and distance between implants.
The establishment of the torque for the initial stability of the implant was a major concern because atrophy as a result
Please cite this article in press as: Maluf PSZ, et al. Insertion torque of dental implants after microvascular fibular grafting. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.03.016
YBJOM-4487; No. of Pages 3
ARTICLE IN PRESS P.S.Z. Maluf et al. / British Journal of Oral and Maxillofacial Surgery xxx (2015) xxx–xxx
of lack of function is a serious problem for maintenance of bone mass and bony remodelling. The use of manual torque wrenches is a simple, accessible way of measuring torque during placement and to control the torque applied to the bone-implant interface, which may prevent overload of the implant. There is a considerable risk of overloading the implant with an electric motor, which stops only when a preset torque is reached. The main criteria for successful osseointegration are no mobility of the implant and no pain when the implant functions.3 The insertion torque ranged from 20 N cm to 45 N cm, and the two that were lost with insertion torques of 20 N cm developed mobility and loss of bone 4 months after placement, which is consistent with reported results.5 Implants with a low insertion torque of 20 N cm were mostly placed in site II, which is the site associated with a more pronounced curvature of the grafted bone used in facial reconstruction. This result confirms the findings of Jaquiéry et al.,2 who reported a comparable success rate and a similar loss of implants, probably associated with insufficient blood supply and low bone density at the recipient site. Further studies are necessary to evaluate the characteristics of the prostheses used in patients who had undergone bony reconstructions, including considerations of problems with oral hygiene and occlusal maintenance.
3
Conflict of interest We have no conflict of interest. Ethics statement/confirmation of patients’ permission The study was approved by the Research Ethics Committee. References 1. Disa JJ, Cordeiro PG. Mandible reconstruction with microvascular surgery. Semin Surg Oncol 2000;19:226–34. 2. Jaquiéry C, Rohner D, Kunz C, et al. Reconstruction of maxillary and mandibular defects using prefabricated microvascular fibular grafts and osseointegrated dental implants – a prospective study. Clin Oral Implants Res 2004;15:598–606. 3. Ottoni JM, Oliveira ZF, Mansini R, et al. Correlation between placement torque and survival of single-tooth implants. Int J Oral Maxillofac Implants 2005;20:769–76. 4. Albrektsson T, Zarb G, Worthington P, et al. The long-term efficacy of currently used dental implants: a review and proposed criteria of success. Int J Oral Maxillofac Implants 1986;1:11–25. 5. Brånemark PI, Zarb GA, Albrektsson T, editors. Tissue-integrated prostheses: osseointegration in clinical dentistry. Chicago: Quintessence; 1985. 6. Goheen KL, Vermilyea SG, Vossoughi J, et al. Torque generated by handheld screwdrivers and mechanical torquing devices for osseointegrated implants. Int J Oral Maxillofac Implants 1994;9:149–55. 7. Rabel A, Köhler SG, Schmidt-Westhausen AM. Clinical study on the primary stability of two dental implant systems with resonance frequency analysis. Clin Oral Investig 2007;11:257–65.
Please cite this article in press as: Maluf PSZ, et al. Insertion torque of dental implants after microvascular fibular grafting. Br J Oral Maxillofac Surg (2015), http://dx.doi.org/10.1016/j.bjoms.2015.03.016
