Assessment of Mandibular Ramus Thickness and Depth for Safe Miniscrew Placement in an Iranian Population: A Cone-Beam Computed Tomography Study
Abstract
Objectives: This study assessed the mandibular ramus for safe miniscrew placement in an Iranian population using cone-beam computed tomography (CBCT).
Materials and Methods: This cross-sectional study was conducted on 212 CBCT scans. The mandibular ramus thickness and depth were measured as the distance between the buccal and lingual surfaces, and the distance between the anterior border of the ramus and the mandibular canal, respectively, at the occlusal plane level and 5mm and 10mm above it. Two-way ANOVA was applied to analyze the effects of gender and presence of third molars on ramus depth and thickness. The right and left sides were compared by paired t-test (alpha=0.05).
Results: As moving from the occlusal plane to 5 and 10mm above it, ramus depth increased while its thickness decreased. In presence of third molars, ramus thickness and depth in males were greater than those in females at both sides. Ramus depth was significantly greater in the right side than the left side at all levels (P<0.001). Presence of third molars (P=0.001, P=0.053) and gender (P<0.001, P=0.052) significantly affected the left-side ramus depth at the occlusal level and 5mm above it. Gender significantly affected the right-side ramus depth at 5 and 10mm levels (P=0.013).
Conclusion: Presence of third molars increased ramus depth and thickness. Ramus depth and thickness were greater in males than females. Miniscrew placement is recommended at 5mm above the occlusal level due to sufficient depth and thickness of the ramus at this region.
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2. Park J, Cho HJ. Three-dimensional evaluation of interradicular spaces and cortical bone thickness for the placement and initial stability of microimplants in adults. Am J Orthod Dentofacial Orthop. 2009 Sep;136(3):314.e1-12; discussion 314-5.
3. Kravitz ND, Kusnoto B. Risks and complications of orthodontic miniscrews. Am J Orthod Dentofacial Orthop. 2007 Apr;131(4 Suppl):S43-51.
4. Baumgaertel S, Hans MG. Buccal cortical bone thickness for mini-implant placement. Am J Orthod Dentofacial Orthop. 2009 Aug;136(2):230-5.
5. Nucera R, Bellocchio AM, Oteri G, Farah AJ, Rosalia L, Giancarlo C, et al. Bone and cortical bone characteristics of mandibular retromolar trigone and anterior ramus region for miniscrew insertion in adults. Am J Orthod Dentofacial Orthop. 2019 Mar;155(3):330-338.
6. Elshebiny T, Palomo JM, Baumgaertel S. Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients. Am J Orthod Dentofacial Orthop. 2018 Apr;153(4):505-511.
7. Wilmes B, Rademacher C, Olthoff G, Drescher D. Parameters affecting primary stability of orthodontic mini-implants. J Orofac Orthop. 2006 May;67(3):162-74. English, German.
8. Marquezan M, Mattos CT, Sant'Anna EF, de Souza MM, Maia LC. Does cortical thickness influence the primary stability of miniscrews?: A systematic review and meta-analysis. Angle Orthod. 2014 Nov;84(6):1093-103.
9. Alharbi F, Almuzian M, Bearn D. Miniscrews failure rate in orthodontics: systematic review and meta-analysis. Eur J Orthod. 2018 Sep 28;40(5):519-530.
10. Zawawi KH. Acceptance of orthodontic miniscrews as temporary anchorage devices. Patient Prefer Adherence. 2014 Jun 30;8:933-7.
11. Papageorgiou SN, Zogakis IP, Papadopoulos MA. Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis. Am J Orthod Dentofacial Orthop. 2012 Nov;142(5):577-595.e7.
12. Baumgaertel S. Cortical bone thickness and bone depth of the posterior palatal alveolar process for mini-implant insertion in adults. Am J Orthod Dentofacial Orthop. 2011 Dec;140(6):806-11.
13. Nucera R, Lo Giudice A, Bellocchio AM, Spinuzza P, Caprioglio A, Perillo L, et al. Bone and cortical bone thickness of mandibular buccal shelf for mini-screw insertion in adults. Angle Orthod. 2017 Sep;87(5):745-751.
14. Franklin D, O'Higgins P, Oxnard CE, Dadour I. Discriminant function sexing of the mandible of indigenous South Africans. Forensic Sci Int. 2008 Jul 18;179(1):84.e1-5.
15. Landin M, Jadhav A, Yadav S, Tadinada A. A comparative study between currently used methods and Small Volume-Cone Beam Tomography for surgical placement of mini implants. Angle Orthod. 2015 May;85(3):446-53.
16. Kim SH, Kang SM, Choi YS, Kook YA, Chung KR, Huang JC. Cone-beam computed tomography evaluation of mini-implants after placement: Is root proximity a major risk factor for failure? Am J Orthod Dentofacial Orthop. 2010 Sep;138(3):264-76.
17. Nakajima A, Sameshima GT, Arai Y, Homme Y, Shimizu N, Dougherty H Sr. Two- and three-dimensional orthodontic imaging using limited cone beam-computed tomography. Angle Orthod. 2005 Nov;75(6):895-903.
18. Cassetta M, Stefanelli LV, Pacifici A, Pacifici L, Barbato E. How accurate is CBCT in measuring bone density? A comparative CBCT-CT in vitro study. Clin Implant Dent Relat Res. 2014 Aug;16(4):471-8.
19. Worthington P. Injury to the inferior alveolar nerve during implant placement: a formula for protection of the patient and clinician. Int J Oral Maxillofac Implants. 2004 Sep-Oct;19(5):731-4.
20. Mehta S, Arqub SA, Sharma R, Patel N, Tadinada A, Upadhyay M, et al. Variability associated with mandibular ramus area thickness and depth in subjects with different growth patterns, gender, and growth status. Am J Orthod Dentofacial Orthop. 2022 Mar;161(3):e223-e234.
21. Chang CH, Lin JS, Roberts WE. Ramus screws: the ultimate solution for lower impacted molars. InSeminars in orthodontics 2018 Mar 1 (Vol. 24, No. 1, pp. 135-154). WB Saunders.
22. Giudice AL, Rustico L, Longo M, Oteri G, Papadopoulos MA, Nucera R. Complications reported with the use of orthodontic miniscrews: A systematic review. Korean J Orthod. 2021 May 25;51(3):199-216.
23. Miyawaki S, Koyama I, Inoue M, Mishima K, Sugahara T, Takano-Yamamoto T. Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2003 Oct;124(4):373-8.
24. Baumgaertel S. Quantitative investigation of palatal bone depth and cortical bone thickness for mini-implant placement in adults. Am J Orthod Dentofacial Orthop. 2009 Jul;136(1):104-8.
25. Humphrey LT, Dean MC, Stringer CB. Morphological variation in great ape and modern human mandibles. J Anat. 1999 Nov;195 ( Pt 4)(Pt 4):491-513.
26. Saini V, Srivastava R, Rai RK, Shamal SN, Singh TB, Tripathi SK. Mandibular ramus: an indicator for sex in fragmentary mandible. J Forensic Sci. 2011 Jan;56 Suppl 1:S13-6.
27. Martin B. Aging and strength of bone as a structural material. Calcif Tissue Int. 1993;53 Suppl 1:S34-9; discussion S39-40.
28. Soltani R, Aghajanpour F, Fard HA, Afshar A, Arab N, Farahani RM, Norouzian M. Morphometric Parameters of the Mandibular Ramus an Indicator for Sex Determination: A Radiographic Study. Research in Medicine: Journal of Research in Medical Sciences. 2021 Jun 1;45(2).
29. G V, Gowri S R M, J A. Sex determination of human mandible using metrical parameters. J Clin Diagn Res. 2013 Dec;7(12):2671-3.
30. Indira AP, Markande A, David MP. Mandibular ramus: An indicator for sex determination - A digital radiographic study. J Forensic Dent Sci. 2012 Jul;4(2):58-62.
31. Schwartz-Dabney CL, Dechow PC. Variations in cortical material properties throughout the human dentate mandible. Am J Phys Anthropol. 2003 Mar;120(3):252-77.
32. Frayer DW, Wolpoff MH. Sexual dimorphism. Annu Rev Anthropol. 1985 Jan:429-73.
33. Rai R, Ranade AV, Prabhu LV, Pai MM, Madhyastha S, Kumaran M. Estudio piloto del ángulo y rama de la mandíbula en la población hindú. International Journal of Morphology. 2007 Jun;25(2):353-6.
34. Fan Q, Wen S, Yuan X, He X, Jian F, Wang Y, et al. Evaluation of optimal parameters for the insertion of mini-implants at the mandibular ramus region based on cone-beam computed tomography. Int Orthod. 2025 Sep;23(3):101005.
35. Wang Y, Sun J, Shi Y, Li X, Wang Z. Buccal bone thickness of posterior mandible for microscrews implantation in molar distalization. Ann Anat. 2022 Oct;244:151993.
36. Alirezaei F, Ghorbanipour R, Chalaki B, Moudi E, Mirzaie M, Seyed Majidi SA. Association between gonial angle and bone thickness in the infrazygomatic crest and mandibular buccal shelf regions for mini-screw insertion in adults: A retrospective study. Int Orthod. 2026 Jun;24(2S):101137.
2. Park J, Cho HJ. Three-dimensional evaluation of interradicular spaces and cortical bone thickness for the placement and initial stability of microimplants in adults. Am J Orthod Dentofacial Orthop. 2009 Sep;136(3):314.e1-12; discussion 314-5.
3. Kravitz ND, Kusnoto B. Risks and complications of orthodontic miniscrews. Am J Orthod Dentofacial Orthop. 2007 Apr;131(4 Suppl):S43-51.
4. Baumgaertel S, Hans MG. Buccal cortical bone thickness for mini-implant placement. Am J Orthod Dentofacial Orthop. 2009 Aug;136(2):230-5.
5. Nucera R, Bellocchio AM, Oteri G, Farah AJ, Rosalia L, Giancarlo C, et al. Bone and cortical bone characteristics of mandibular retromolar trigone and anterior ramus region for miniscrew insertion in adults. Am J Orthod Dentofacial Orthop. 2019 Mar;155(3):330-338.
6. Elshebiny T, Palomo JM, Baumgaertel S. Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients. Am J Orthod Dentofacial Orthop. 2018 Apr;153(4):505-511.
7. Wilmes B, Rademacher C, Olthoff G, Drescher D. Parameters affecting primary stability of orthodontic mini-implants. J Orofac Orthop. 2006 May;67(3):162-74. English, German.
8. Marquezan M, Mattos CT, Sant'Anna EF, de Souza MM, Maia LC. Does cortical thickness influence the primary stability of miniscrews?: A systematic review and meta-analysis. Angle Orthod. 2014 Nov;84(6):1093-103.
9. Alharbi F, Almuzian M, Bearn D. Miniscrews failure rate in orthodontics: systematic review and meta-analysis. Eur J Orthod. 2018 Sep 28;40(5):519-530.
10. Zawawi KH. Acceptance of orthodontic miniscrews as temporary anchorage devices. Patient Prefer Adherence. 2014 Jun 30;8:933-7.
11. Papageorgiou SN, Zogakis IP, Papadopoulos MA. Failure rates and associated risk factors of orthodontic miniscrew implants: a meta-analysis. Am J Orthod Dentofacial Orthop. 2012 Nov;142(5):577-595.e7.
12. Baumgaertel S. Cortical bone thickness and bone depth of the posterior palatal alveolar process for mini-implant insertion in adults. Am J Orthod Dentofacial Orthop. 2011 Dec;140(6):806-11.
13. Nucera R, Lo Giudice A, Bellocchio AM, Spinuzza P, Caprioglio A, Perillo L, et al. Bone and cortical bone thickness of mandibular buccal shelf for mini-screw insertion in adults. Angle Orthod. 2017 Sep;87(5):745-751.
14. Franklin D, O'Higgins P, Oxnard CE, Dadour I. Discriminant function sexing of the mandible of indigenous South Africans. Forensic Sci Int. 2008 Jul 18;179(1):84.e1-5.
15. Landin M, Jadhav A, Yadav S, Tadinada A. A comparative study between currently used methods and Small Volume-Cone Beam Tomography for surgical placement of mini implants. Angle Orthod. 2015 May;85(3):446-53.
16. Kim SH, Kang SM, Choi YS, Kook YA, Chung KR, Huang JC. Cone-beam computed tomography evaluation of mini-implants after placement: Is root proximity a major risk factor for failure? Am J Orthod Dentofacial Orthop. 2010 Sep;138(3):264-76.
17. Nakajima A, Sameshima GT, Arai Y, Homme Y, Shimizu N, Dougherty H Sr. Two- and three-dimensional orthodontic imaging using limited cone beam-computed tomography. Angle Orthod. 2005 Nov;75(6):895-903.
18. Cassetta M, Stefanelli LV, Pacifici A, Pacifici L, Barbato E. How accurate is CBCT in measuring bone density? A comparative CBCT-CT in vitro study. Clin Implant Dent Relat Res. 2014 Aug;16(4):471-8.
19. Worthington P. Injury to the inferior alveolar nerve during implant placement: a formula for protection of the patient and clinician. Int J Oral Maxillofac Implants. 2004 Sep-Oct;19(5):731-4.
20. Mehta S, Arqub SA, Sharma R, Patel N, Tadinada A, Upadhyay M, et al. Variability associated with mandibular ramus area thickness and depth in subjects with different growth patterns, gender, and growth status. Am J Orthod Dentofacial Orthop. 2022 Mar;161(3):e223-e234.
21. Chang CH, Lin JS, Roberts WE. Ramus screws: the ultimate solution for lower impacted molars. InSeminars in orthodontics 2018 Mar 1 (Vol. 24, No. 1, pp. 135-154). WB Saunders.
22. Giudice AL, Rustico L, Longo M, Oteri G, Papadopoulos MA, Nucera R. Complications reported with the use of orthodontic miniscrews: A systematic review. Korean J Orthod. 2021 May 25;51(3):199-216.
23. Miyawaki S, Koyama I, Inoue M, Mishima K, Sugahara T, Takano-Yamamoto T. Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2003 Oct;124(4):373-8.
24. Baumgaertel S. Quantitative investigation of palatal bone depth and cortical bone thickness for mini-implant placement in adults. Am J Orthod Dentofacial Orthop. 2009 Jul;136(1):104-8.
25. Humphrey LT, Dean MC, Stringer CB. Morphological variation in great ape and modern human mandibles. J Anat. 1999 Nov;195 ( Pt 4)(Pt 4):491-513.
26. Saini V, Srivastava R, Rai RK, Shamal SN, Singh TB, Tripathi SK. Mandibular ramus: an indicator for sex in fragmentary mandible. J Forensic Sci. 2011 Jan;56 Suppl 1:S13-6.
27. Martin B. Aging and strength of bone as a structural material. Calcif Tissue Int. 1993;53 Suppl 1:S34-9; discussion S39-40.
28. Soltani R, Aghajanpour F, Fard HA, Afshar A, Arab N, Farahani RM, Norouzian M. Morphometric Parameters of the Mandibular Ramus an Indicator for Sex Determination: A Radiographic Study. Research in Medicine: Journal of Research in Medical Sciences. 2021 Jun 1;45(2).
29. G V, Gowri S R M, J A. Sex determination of human mandible using metrical parameters. J Clin Diagn Res. 2013 Dec;7(12):2671-3.
30. Indira AP, Markande A, David MP. Mandibular ramus: An indicator for sex determination - A digital radiographic study. J Forensic Dent Sci. 2012 Jul;4(2):58-62.
31. Schwartz-Dabney CL, Dechow PC. Variations in cortical material properties throughout the human dentate mandible. Am J Phys Anthropol. 2003 Mar;120(3):252-77.
32. Frayer DW, Wolpoff MH. Sexual dimorphism. Annu Rev Anthropol. 1985 Jan:429-73.
33. Rai R, Ranade AV, Prabhu LV, Pai MM, Madhyastha S, Kumaran M. Estudio piloto del ángulo y rama de la mandíbula en la población hindú. International Journal of Morphology. 2007 Jun;25(2):353-6.
34. Fan Q, Wen S, Yuan X, He X, Jian F, Wang Y, et al. Evaluation of optimal parameters for the insertion of mini-implants at the mandibular ramus region based on cone-beam computed tomography. Int Orthod. 2025 Sep;23(3):101005.
35. Wang Y, Sun J, Shi Y, Li X, Wang Z. Buccal bone thickness of posterior mandible for microscrews implantation in molar distalization. Ann Anat. 2022 Oct;244:151993.
36. Alirezaei F, Ghorbanipour R, Chalaki B, Moudi E, Mirzaie M, Seyed Majidi SA. Association between gonial angle and bone thickness in the infrazygomatic crest and mandibular buccal shelf regions for mini-screw insertion in adults: A retrospective study. Int Orthod. 2026 Jun;24(2S):101137.
| Issue | Vol 23 (Continuously Published Article-Based) | |
| Section | Original Article | |
| Keywords | ||
| Cone-Beam Computed Tomography Mandibular Condyle Orthodontic Anchorage Procedures | ||
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How to Cite
1.
Tamartash F, Pornamazeh Y. Assessment of Mandibular Ramus Thickness and Depth for Safe Miniscrew Placement in an Iranian Population: A Cone-Beam Computed Tomography Study. Front Dent. 2026;23.
