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The Importance of Abfractions

To read an article on the definition, cause and clinical implication of Dental Abfractions Click Here

Noncarious dental "abfraction" lesions in an aging population.
Compend Contin Educ Dent 1995 Jun;16(6):552, 554,
Owens BM; Gallien GS ,Department of General Dentistry, University of Tennessee, College of Dentistry, Memphis, USA.

A new classification for noncarious dental lesions has evolved from the dental literature. The name given to these lesions, dental "abfractions," is a theory propounding tooth fatigue, flexure, and deformation through biomechanical loading of tooth structure, primarily at the cervical regions of the dentition. These lesions are typically wedge shaped with sharp line angles, but occlusal abfractions have been observed as circular invaginations. Dental abfractions can occur alone and are sometimes associated with toothbrush abrasion and erosion from endogenous or exogenous acids. Treatment consists of the application of composite resin or glass-ionomer cement restorations and/or the discontinuance of the etiology of these lesions. If esthetics are not a primary concern of the patient and the tooth is not structurally compromised, many of these lesions can be observed, provided that the patient is informed that bruxism or malocclusion problems exist.

The role of cuspal flexure in the development of abfraction lesions: a finite element study.

Eur J Oral Sci 1998 Dec;106(6):1028-32

Rees JS, Department of Oral and Dental Science, Dental School, University of Bristol, UK

A tooth flexure mechanism has been proposed over the past 15 yr to explain non-carious cervical tooth loss. It is well established that cavity preparation weakens a tooth, resulting in more cuspal movement under occlusal load. The aim of this study was to investigate the effect that an occlusal restoration would have on the stress profile in the cervical region of a lower second premolar using two-dimensional finite element stress analysis. Under an eccentric 100 N occlusal load, a premolar with an occlusal amalgam restoration showed peak tensile and shear stresses in the buccal cervical region that were in excess of the known failure stress for enamel. Increases in the cavity depth of the occlusal amalgam restoration were found to increase cervical stress more than increases in cavity width. It was concluded that the weakening effect of cavity preparation may contribute to the development of non-carious cervical tooth loss.

Stress-induced cervical lesions: review of advances in the past 10 years.

J Prosthet Dent 1996 May;75(5):487-94

Lee WC; Eakle WS, Department of Restorative Dentistry, University of California, San Francisco, USA.

The accumulation of experimental and clinical evidence during the past decade has significantly contributed to the understanding of the role of occlusally generated tensile stress in the etiology of certain noncarious cervical lesions of teeth. More important, this knowledge has led to the understanding of the reasons why traditional restorative treatments of these stress-induced cervical lesions fail. The case of failure can be attributed to the occlusally generated stresses that are concentrated at the cervical region and result in debonding, leakage, retention failure, and, ultimately, restorative failure. With the new understanding, restorative approaches that combine chemical adhesion and restorative materials of appropriate elastic properties show promise of long-term success.

  Brackett, et al.-1999-Two-year clinical performance of a resin-modified glass-ionomer restorative material.-Oper Dent-24-9-13-

This study was a 2-year clinical evaluation of a conventional and a resin-modified glass-ionomer restorative material. Thirty-four restorations each of Ketac-Fil and Photac-Fil were placed without tooth preparation in cervical abrasion/abfraction lesions, primarily in premolar teeth. Patients ranged in age from 30 to 73 years, with a median age of 45 years. Isolation for the restorations was accomplished with cotton rolls. Restorations of both materials were retained at the rate of 93%, and both were comparable in appearance, receiving Alfa ratings for more than 85% of the restorations. One occurrence of secondary caries was observed for each material. No significant difference between the materials was observed for any evaluation category (exact binomial test, P > 0.05).,

Brackett, et al.-1999-1-year clinical evaluation of Compoglass and Fuji II LC in cervical erosion/abfraction lesions.-Am J Dent-12-119-22-

PURPOSE: This study was undertaken to compare the clinical performance of a polyacid-modified resin-based composite and a resin-modified glass-ionomer restorative material over 1 year.
MATERIALS & METHODS: Thirty-four pairs of restorations of Compoglass (C) and Fuji II LC (F) were placed in 31 patients, with no patient receiving more than two pairs, and with materials assigned at random within the pairs. Caries-free cervical erosion/abfraction lesions of the facial surface were restored without tooth preparation according to manufacturers' instructions, except that tooth structure to be restored was etched with 37% phosphoric acid prior to placement of Compoglass. Restorations were clinically evaluated by two blinded examiners at baseline, 6 months, and 1 year, using modified Ryge/USPHS criteria. Restorations receiving a score of "Charlie" in either retention or secondary caries were classified as failed restorations. The incidence of failures was statistically analyzed as a pairwise comparison, using an exact binomial test.
RESULTS: Thirty-one pairs of restorations were available for recall at 1 year. The percentage of Alfa scores for each material in each category were: Retention (C = 84%, F = 100%), Color match (C = 81%, F = 100%), Marginal discoloration (C = 78%, F = 97%), Secondary caries (C = 88%, F = 100%), Anatomic form (C = 92%, F = 100%), and Marginal adaptation (C = 26%, F = 46%). Except for the failed restorations, no other Charlie scores were assigned. A significant difference in the incidence of failed restorations was found between the materials (P = 0.01).,

Leinfelder-1994-Restoration of abfracted lesions.-Compendium-15-1396, 1398-1400; quiz 1400-

This article discusses the latest clinical findings regarding the cause of cervical lesions. Certain preparation and bonding techniques are recommended for restoring these abfractures. In particular, the composite restoratives are explained and a guide is provided for choosing the most suitable materials.,

J Clin Periodontol 2000 Feb;27(2):99-103

Studies in vitro of abrasion by different manual toothbrush heads and a standard toothpaste.
Dyer D, Addy M, Newcombe RG
Division of Restorative Dentistry, Dental School, Bristol, UK.


BACKGROUND: Loss of dentine at the buccal cervical region of teeth has a multifactorial aetiology. However, a considerable amount of circumstantial evidence, supported by laboratory experiments, implicates toothbrushing with toothpaste as a consistent factor. Most interest has centred around the abrasivity of toothpastes, particularly since a toothbrush alone has negligible effects on dentine. The influence of filament stiffness on toothpaste abrasion was the subject of some studies, mostly at least 2 decades ago, and produced conflicting conclusions. Numerous changes to toothbrush design and construction have taken place in recent years.
AIMS: The aim of this study was to measure the abrasion of a standard substrate, acrylic, by a standard toothpaste carried on modern brands of toothbrushes classified by manufacturers as hard (3 brands), medium (3 brands) and soft (6 brands).
METHOD: The substrate was brushed for 20,000 strokes with at least 6 heads from each brand. Measurements of substrate loss were made at 5000 stroke increments by profilometry.
RESULTS: Substrate loss for all brushes showed a pattern of abrasion which was to a first approximation linear. Overall, hard brushes caused least abrasion and soft brushes the most, with differences between groups being significant. Within-group differences between brands reached significance for soft and medium brushes but not hard brushes.
CONCLUSIONS: The results could be explained by increased retention of toothpaste by smaller diameter filaments and denser tufts on soft brushes and the greater flexion of filaments increasing the area of contact with the surface. Calculations on the clinical outcome of these data in vitro indicate that toothbrushing with toothpaste alone would produce minimal damage to dentine even over many years. Differences between brushes therefore are probably of little clinical significance. Certainly, the data do not support the use of hard brushes, particularly in view of the potential detrimental effects to gingival tissues.

Int Dent J 1999 Jun;49(3):139-43

The aetiology of the non-carious cervical lesion. 

Osborne-Smith KL, Burke FJ, Wilson NH
Department of Restorative Dentistry, University Dental Hospital of Manchester, UK.

Erosion and abrasion have been widely reported as causes of non-carious cervical lesions (NCCL). However, more recently, tooth flexure has been implicated in the formation of these lesions generating renewed interest in the pathogenesis of the non-carious loss of cervical tooth substance. This paper considers the causes of erosion and abrasion, related to modern lifestyles, and reviews the literature concerning tooth flexure as a cause of NCCL. A description of different types of NCCL is given, as an aid to determining the aetiology, yet at the same time accepting that the causation and pathogenesis of NCCL is probably multi-factorial resulting in many different clinical presentations. Consideration is given to the indications for treatment of NCCL and to the selection of materials for restoring such defects.

Esthet Dent 1999;11(4):215-22 Related Articles, Books, LinkOut
Potential for load-induced cervical stress concentration as a function of periodontal support. 

Kuroe T, Itoh H, Caputo AA, Nakahara H
Division of Advanced Prosthodontics, Biomaterials Science, and Hospital Dentistry, UCLA School of Dentistry, USA.

PURPOSE: The purpose was to determine, photoelastically, the locations of occlusal load-induced stress concentrations within a maxillary premolar as a function of degree of periodontal support.
MATERIALS & METHODS: Composite three-dimensional models of a maxillary first premolar were fabricated for quasi-three-dimensional photoelastic stress analysis. Individual materials were used to model enamel, dentin, periodontal ligament, and alveolar bone. Three levels of periodontal support reduction (0%, 20%, 25%) were simulated by varying the socket depth. Vertical loads of 10 lb were applied to: (1) tip of buccal cusp, (2) tip of lingual cusp, and (3) center of occlusal surface. The resulting stresses were monitored and recorded photographically in the field of a circular polariscope arrangement.
RESULTS: Cuspal loading concentrated stress around the cervical region below the loaded cusp, being highest under buccal cusp loading. The location of the stress concentration shifted apically as periodontal support diminished.
CLINICAL SIGNIFICANCE:: Observed cervical stress concentration corresponded well to the common location of abfractions seen in clinical situations. Since the location of cervical stress concentration varied with occlusal conditions, occurrence of abfractions must be highly dependent upon each patient's occlusion. Periodontal support reduction shifted the location of highest stress away from the cementoenamel junction. Therefore, abfractions are less likely to occur on periodontally compromised teeth compared to stable teeth.

J Esthet Dent 1999;11(6):332-7 Related Articles, Books, LinkOut
Development of noncarious cervical notch lesions in vitro.
Whitehead SA, Wilson NH, Watts DC
Unit of Operative Dentistry and Endodontology, University of Manchester Dental Hospital, United Kingdom.

PURPOSE: The initiation and progression of noncarious cervical notch lesions (NCCL) continues to perplex clinicians worldwide and poses a considerable restorative challenge. The purpose of this brief communication is to report what is believed to be the first in vitro production of notch-shaped lesions in the cervical third of premolar teeth.
MATERIALS & METHODS: The lesions, were produced by axial loading of selected permanent premolar teeth in a 10% aqueous solution of sulfuric acid over a period of 5 days, followed by immersion in water for 7 days.
RESULTS: Results revealed macroscopic and microscopic features similar to those observed in noncarious cervical lesions in vivo. The lesions were incidental findings while the authors were studying stress corrosion of enamel at low pH. Although much remains to be investigated regarding the etiology and pathogenesis of NCCL, axial loading and a corrosive environment may be implicated in these processes. The artificial lesions arose in clinically sound teeth, suggesting that there is no simple clinical examination to identify teeth at risk from NCCL.
CLINICAL SIGNIFICANCE:: The relationship between the development of NCCL and applied stress indicates that occlusal factors may play the most significant role in the initiation and progression of NCCL.

Coll Antropol 1999 Dec;23(2):651-7

The influence of tooth wear on root canal dimensions. 

Keros J, Bagic I, Verzak Z, Bukovic D Jr, Staudt-Skaljac G
Department of Dental Anthropology, Dental School, University of Zagreb, Croatia.

The objective was to investigate the relations between tooth wear and root canal dimensions. The experimental group comprised 100 cuspids (canines), 50 of which had advanced abrasion and 50 were without it The dimensions of root canal were investigated at the light microscope level in order to define their vestibulo-oral and mesio-distal diameters in all three thirds. In the groups of teeth without abrasion the MD diameters of root canaliculi in their cervical thirds were greater than in the teeth with advanced abrasion. In the apical third the MD diameters of canaliculi were highly variable in teeth with no signs of abrasion. In the group of teeth with abrasion the MD and VO diameter values of the cervical thirds were significantly smaller than in the group of teeth without abrasion. In the mid-thirds the values of MD diameters were highly variable in the group of teeth with abrasion, whereas the VO diameter values were much greater than in the teeth without abrasion. As regards to the apical thirds, the VO diameter values were greater than in the control teeth. The data presented herewith contribute to better knowledge about tooth wear and are highly useful in restorative and reconstructive dental procedures.

Am J Dent 1998 Feb;11(1):29-32 Related Articles, Books, LinkOut
Association of occlusal, periodontal, and dietary factors with the presence of non-carious cervical dental lesions.
Mayhew RB, Jessee SA, Martin RE
Department of Health, Promotion and Dental Care Delivery, University of Texas Health Science Center at Houston, USA.

PURPOSE: To investigate in vivo the relationship of occlusal stress factors, periodontal health status, and acidic dietary patterns to the presence of non-carious cervical lesions (NCCL) in a convenience sample of undergraduate clinic, adult dental patients.
MATERIALS & METHODS: Forty three subjects who met the entry criteria were admitted into the study; 178 teeth exhibiting NCCL were evaluated. A dietary assessment focusing on acidic food/beverage intake was used to evaluate nutritional intake over the most recent 24-hour period. Periodontal evaluation included intraoral measurement of gingival attachment loss, assessment of tooth mobility, and radiographic interpretation of percent bone loss using the Schei ruler method. Among the occlusal factors evaluated were shape and orientation of NCCL, presence and location of wear facets, and symptoms and characteristics of centric and eccentric occlusal function.
RESULTS: 95% of teeth examined exhibited functional wear facets, indicating a systematic relationship with presence of NCCL (Chi Square = 16.9, P < 0.0001); 48% displayed buccal or incisal facets; 64% were accompanied by balancing interferences in lateral excursion; 98.3% had mobility scores < or = 1; there was no significant association between mobility and facets present (Chi Square = 3.04, P = 0.21); and, no relationship with dietary patterns was found. Group function, that may evolve with age, and/or traumatic occlusion factors may be related to etiology of NCCL. Longitudinal controlled clinical trials are needed to confirm suspected etiologies and establish treatment guidelines for non-carious cervical lesions.

Association of occlusal, periodontal, and dietary factors with the presence of non-carious cervical dental lesions.
Mayhew RB; Jessee SA; Martin RE
Department of Health, Promotion and Dental Care Delivery, University of Texas Health Science Center at Houston, USA.
Am J Dent Feb 1998 11 (1) p29-32
Language: ENGLISH
PURPOSE: To investigate in vivo the relationship of occlusal stress factors, periodontal health status, and acidic dietary patterns to the presence of non- carious cervical lesions (NCCL) in a convenience sample of undergraduate clinic, adult dental patients.
MATERIALS & METHODS: Forty three subjects who met the entry criteria were admitted into the study; 178 teeth exhibiting NCCL were evaluated. A dietary assessment focusing on acidic food/beverage intake was used to evaluate nutritional intake over the most recent 24-hour period. Periodontal evaluation included intraoral measurement of gingival attachment loss, assessment of tooth mobility, and radiographic interpretation of percent bone loss using the Schei ruler method. Among the occlusal factors evaluated were shape and orientation of NCCL, presence and location of wear facets, and symptoms and characteristics of centric and eccentric occlusal function.
RESULTS: 95% of teeth examined exhibited functional wear facets, indicating a systematic relationship with presence of NCCL (Chi Square = 16.9, P < 0.0001); 48% displayed buccal or incisal facets; 64% were accompanied by balancing interferences in lateral excursion; 98.3% had mobility scores < or = 1; there was no significant association between mobility and facets present (Chi Square = 3.04, P = 0.21); and, no relationship with dietary patterns was found. Group function, that may evolve with age, and/or traumatic occlusion factors may be related to etiology of NCCL. Longitudinal controlled clinical trials are needed to confirm suspected etiologies and establish treatment guidelines for non-carious cervical lesions.

Effect of restored and unrestored non-carious cervical lesions on the fracture resistance of previously restored maxillary premolar teeth.
Osborne-Smith KL; Burke FJ; Farlane TM; Wilson NH
University Dental Hospital of Manchester, UK.
J Dent Jul-Aug 1998 26 (5-6) p427-33
Language: ENGLISH

OBJECTIVES: The effect of non-carious cervical lesions (NCCL) on tooth fracture resistance has not previously been investigated. The aims of this in vitro study were to examine the fracture resistance of a group of extracted maxillary premolar teeth with mesio-occlusal-distal (MOD) restorations of amalgam, and restored or unrestored simulated NCCL.
METHOD: Forty sound maxillary, premolar teeth were divided at random into four groups, each of 10 teeth, which were fixed crown uppermost and long axis vertical in stainless steel moulds. Groups 1,2,3 and 4 were prepared with standardized parallel- sided MOD cavities, then restored with amalgam. Groups 1, 2 and 3 were further prepared with standardized NCCL. The NCCL in Group 1 were restored using a resin-modified polyalkenoate (glass-ionomer) cement, and the NCCL in Group 2 were restored with an adhesive composite resin system. The NCCL in Group 3 were left unrestored. The specimens were loaded compressively at 1 mm min-1 using a universal testing machine.
RESULTS: Mean fracture loads (KN) of 1.08, 1.03, 0.98 and 1.14, respectively, were recorded for Groups 1, 2, 3 and 4. Two- way ANOVA and Scheffe's Multiple Range Test showed no statistically significant difference between the groups. CONCLUSIONS: It is concluded that the presence of a standardized NCCL in an extracted maxillary premolar tooth does not reduce the fracture resistance of the tooth when loaded compressively at 1 mm min-1. The restoration of NCCL with the materials tested did not result in an increase in the fracture resistance of the previously restored premolar teeth, when loaded compressively at 1 mm min-1.

Dental erosion. Definition, classification and links.
Imfeld T
Clinic of Preventive Dentistry, Periodontology and Cardiology, Dental Institute, University of Zurich, Switzerland.
Eur J Oral Sci Apr 1996 104 (2 ( Pt 2)) p151-5
Language: ENGLISH
An overview of tooth wear, i.e. of non-carious destructive processes affecting the teeth including abrasion, demastication, attrition, abfraction, resorption and erosion is presented. The nomenclature and classification of dental erosion commonly used in the dental literature are summarized. They are based on etiology (extrinsic, intrinsic, idiopathic), on clinical severity (Classes I to III), on pathogenetic activity (manifest, latent) or on localization (perimolysis). Interactions between erosion and abrasion, demastication, attrition, and abfraction as well as caries and low salivary flow rate are highlighted.

Case-control study of non-carious cervical lesions.
Bader JD; McClure F; Scurria MS; Shugars DA; Heymann HO
School of Dentistry, University of North Carolina, Chapel Hill 27599-7590, USA.
Community Dent Oral Epidemiol Aug 1996 24 (4) p286-91
Language: ENGLISH
An exploratory case-control study of non-carious cervical lesions was undertaken to examine the effects of a variety of risk factors. Candidate exposure variables were related to erosion, abrasion, and tooth flexure, the three principal putative causal mechanisms for cervical lesions. Because previous studies have tended to focus on specific causal mechanisms, evidence for a multifactorial etiology is inconclusive. Data describing exposure factors were obtained through clinical examination, dietary and behavioral questionnaires, and analysis of study casts from 264 subjects (137 cases, 127 control). Salivary data were also obtained for a subset of these subjects. Patient and tooth-level logistic regression models were constructed for the full subject group, and the subset with salivary data. For the two patient- level models, only exposures related to brushing entered. For tooth-level models, multiple exposures representing all three causal mechanisms were included in both models. The results suggest that non-carious cervical lesions do have a multifactorial etiology, and that multiple causal mechanisms may operate in the initiation and progression of individual lesions.

Gallien, et al.-1994-A review of noncarious dental cervical lesions.-Compendium-15-1366, 1368-72, 1374; quiz 1374

Noncarious dental cervical lesions are categorized as abrasions, attritions, erosions, or abfractions. From these destructive processes, hypersensitive dentin is a common sequela experienced by the dental patient. Cold air and tactile probing are among the stimuli that precipitate this reaction. A complete patient history and clinical evaluation are essential for an accurate diagnosis. Treatment measures for hypersensitive dentin include restoring the lesion with composite resin or glass-ionomer material, the application of dentin bonding agents and/or fluoride, and iontophoresis therapy.,

Imfeld-1996-Dental erosion. Definition, classification and links.-Eur J Oral Sci-104- p151-5-

An overview of tooth wear, i.e. of non-carious destructive processes affecting the teeth including abrasion, demastication, attrition, abfraction, resorption and erosion is presented. The nomenclature and classification of dental erosion commonly used in the dental literature are summarized. They are based on etiology (extrinsic, intrinsic, idiopathic), on clinical severity (Classes I to III), on pathogenetic activity (manifest, latent) or on localization (perimolysis). Interactions between erosion and abrasion, demastication, attrition, and abfraction as well as caries and low salivary flow rate are highlighted.