An overhanging dental restoration (ODR) is defined as an excess of restorative material, extending beyond cavity preparation borders.[i] ODRs are common causes of gingival inflammation and periodontal damage. Working in a very limited area in the mouth and having difficulties accessing certain teeth can lead to ODR, which is a particular problem in interproximal areas. In these regions, polishing procedures that reduce micro environments for bacteria are more challenging – particularly at the disto-occlusal margins of maxillary molars.[ii]
The prevalence of ODRs is remarkably high.[iii] However, with careful treatment planning, and with the use of appropriate methodology, clinicians can reduce the impact, or completely avoid the formation of overhangs.[iv]
The prevalence and impact of overhanging restorations
Prevalence varies depending on the population and restorative material studied. Overhanging restorations have been identified in anything between 25-76% of all restored surfaces.[v] ODRs are often found in posterior teeth, particularly molars and premolars, and are more prevalent in the maxilla compared to the mandible.ii In one study, featuring the panoramic radiographs of 243 patients with one or more restoration, a total of 280 overhanging restorations were detected. More than half of the overhangs in this study were reported at the distal margins of Class II restorations, which are located between the molars.ii
Overhangs can create crevices and micro-gaps that make it difficult for patients to maintain adequate oral hygiene. The accumulation of plaque in these regions leads to the development of destructive subgingival flora,[vi] causing inflammation of the gingiva. Over time, this can lead to periodontitis, characterised by alveolar bone loss and possible tooth mobility.[vii]
The anatomical shape of the tooth, the type of restorative material, and the location of the overhang all play a role in how easily plaque can accumulate. Particularly when the restoration is near the gumline, where the gingival sulcus is formed subgingivally, the gingiva can be directly irritated. This irritation can damage the epithelial tissue and subepithelial connective tissue, making it harder for the tissues to heal and maintain a healthy attachment to the tooth.i
The role of technique and materials in overhanging restorations
The role of technique and materials in overhanging restorationsWhile ODRs can be exacerbated by unusual tooth morphology or access problems, overhangs are predominantly iatrogenic.[viii] Poor cavity preparation, inappropriate matrix band selection, improper wedging, and excessive material placement can all lead to the formation of overhangs.[ix]
While both amalgam and composite restorations can be associated with ODRs, amalgam fillings tend to be more prone to marginal failure. In one study, overhanging margins in amalgam restorations had 4 times the prevalence of composite restorations.[x] However, composites can also create overhanging margins if not placed carefully.[xi] Whether using amalgam or composite, dentists must be meticulous in their approach to avoid complications.
Prevention and treatment of overhanging restorations
Dentists must take care to place restorative material precisely, ensuring that it does not extend past the tooth’s natural contours. Choosing the correct matrix band is essential to achieving a properly contoured restoration. A well-adapted matrix ensures that the restorative material is contained within the preparation margins, preventing overhangs from forming.[xii]
Proper wedging stabilises the matrix band and helps to prevent excessive material from extruding beyond the preparation margins. This is especially important in Class II restorations, where the contact point between adjacent teeth must be recreated accurately.[xiii]
Small overhangs can often be corrected or refined by smoothing out the margins of the restorative material.[xiv] In cases where the overhang is severe or causing significant periodontal damage, the entire restoration may need to be removed and replaced.[xv]
Tools and techniques for effective treatment
Tools and techniques for effective treatmentIn order to manage overhanging restorations, a high quality 1:1 handpiece will allow appropriate finishing and polishing without causing damage. The Synea Fusion handpiece from W&H, offers an efficient, durable optic perfect for the job. If larger quantities of harder advanced ceramic materials, such as zirconia, require removal then you can benefit from specialised handpieces designed for the purpose such as the Synea Fusion Power Edition. With a small head, the Synea Fusion range is designed for optimal access when treating hard-to-reach areas. Precise and powerful action allows clinicians to efficiently and accurately remove excess material, as well as to polish and contour restorations.
Taking into account the possible consequences of ODRs, dentists should take proactive steps to prevent their formation. Through careful restoration techniques, regular monitoring, and early intervention, it is possible to prevent or minimise the impact of overhanging restorations, protecting patients’ periodontal health.
Maryam Tavangar1, Farideh Darabi1, Reza Tayefeh
Davalloo1, Bardia vadiati Saberi2, Yousef Jahandideh3,
Ehsan Kazemnejad Leili4, Niloofar Tashayodi
To find out more about the full range from W&H, visit www.wh.com/en_uk, call 01727 874990 or email office.uk@wh.com
[i] Al-Kholani AI, An Evaluation of Overhanging Dental Restorations’ Frequency and Localization in a Group of Yemeni People in Sana’a City – Yemen. Ann Clin Med Case Rep. 2024; V14(4): 1-6
[ii] Tekbaş A. M., Büyükgöze Dindar M., Özyurt E., Çilingir E., Erdemir U. Frequency and Localization of Overhanging Restorations. Cumhuriyet Dent J 2020;23:2;116-123
[iii] Tavangar M, Darabi F, Davalloo RT, Saberi BV, Jahandideh Y, Leili EK, Tashayodi N. The Prevalence of Restoration Overhang in Patients Referred to the Dental Clinic of Guilan University of Medical Sciences. June 2016 Journal of Dentomaxillofacial Radiology Pathology and Surgery 5(1):18-23 DOI:10.18869/acadpub.3dj.5.1.18
[iv] Sivakumar A, Thangaswamy V, Ravi V. Treatment planning in conservative dentistry. J Pharm Bioallied Sci. 2012 Aug;4(Suppl 2):S406-9. doi: 10.4103/0975-7406.100305. PMID: 23066299; PMCID: PMC3467905.
[v] Brunsvold, M.A. and Lane, J.J. (1990), The prevalence of overhanging dental restorations and their relationship to periodontal disease. Journal of Clinical Periodontology, 17: 67-72. https://doi.org/10.1111/j.1600-051X.1990.tb01064.x
[vi] Lang NP, Kiel RA, Anderhalden K. Clinical and microbiological effects of subgingival restorations with overhanging or clinically perfect margins. J Clin Periodontol. 1983 Nov;10(6):563-78. doi: 10.1111/j.1600-051x.1983.tb01295.x. PMID: 6581173.
[vii] Bhuyan R, Bhuyan SK, Mohanty JN, Das S, Juliana N, Juliana IF. Periodontitis and Its Inflammatory Changes Linked to Various Systemic Diseases: A Review of Its Underlying Mechanisms. Biomedicines. 2022; 10(10):2659. https://doi.org/10.3390/biomedicines10102659
[viii] Fauzia Quadir, S. Yawar Ali Abidi and Shahbaz Ahmed. Overhanging Amalgam Restorations by Undergraduate Students. Journal of the College of Physicians and Surgeons Pakistan 2014, Vol. 24 (7): 485-488. Available at: https://www.jcpsp.pk/archive/2014/Jul2014/09.pdf
[ix] Stevenson RG. Best practices: Restorative complications. Avoiding and Treating Dental Complications: Best Practices in Dentistry, First Edition. Edited by Deborah A. Termeie. © 2016 John Wiley & Sons, Inc. Published 2016 by John Wiley & Sons, Inc.
[x] Levin L, Coval M, Geiger SB. Cross-sectional radiographic survey of amalgam and resin-based composite posterior restorations. Quintessence Int. 2007 Jun;38(6):511-4. PMID: 17625635.
[xi] B.A.C. Loomans, N.J.M. Opdam, F.J.M. Roeters, E.M. Bronkhorst, M.C.D.N.J.M. Huysmans,
Restoration techniques and marginal overhang in Class II composite resin restorations, Journal of Dentistry, Volume 37, Issue 9, 2009, Pages 712-717, ISSN 0300-5712, https://doi.org/10.1016/j.jdent.2009.05.025.
[xii] Vaishnavi Rajendra Patekar, Nikhil Mankar, Karuna Burde, Aparna Achanta. Choice of Matrix System in Dentistry, J Res Med Dent Sci, 2022, 10 (11): 120-126.
[xiii] Gancedo-Gancedo T, Martín-Biedma B, Domínguez-Cachón J, Garrido-Parada S, Ababii V, Pereira-Lores P, García-Varela S, Castelo-Baz P. New Technique for Wedge Selection in Direct Class II Restorations: A Pilot Study. J Clin Med. 2024 Feb 26;13(5):1324. doi: 10.3390/jcm13051324. PMID: 38592699; PMCID: PMC10931775.
[xiv] Matvijenko VB, Živković MV, Mitić AD, Popović JZ, Kostić LB, Živković DM, Perić, D. M. Effect of irregular interproximal periodontal status. dental restorations on Acta stomatologica Naissi 2012;28:1144-1154.
[xv] Igor R Blum, Daryll C Jagger, Nairn H F Wilson. Defective dental restorations: to repair or not to repair? part 1: direct composite restorations. Dental Update 2025 38:2, 707-709.
