Lessons learned from the Cracked Tooth Registry: A 3-year clinical study in the Nation's Network.

BACKGROUND: This article reviews the most salient lessons learned from a large, multisite, 3-year observational study of posterior teeth with cracks conducted by The National Dental Practice-Based Research Network. TYPES OF STUDIES REVIEWED: Eight articles published over a 6-year period (2017-2022) describing clinical characteristics of posterior teeth with cracks and their treatment and outcomes are reviewed and discussed to answer 3 common questions faced by oral health care clinicians: Which cracked teeth will get worse? When should practitioners intervene? What is the best treatment? RESULTS: Although cracks in teeth are prevalent, few will fracture (3%) or show crack progression in 3 years (12%). Characteristics that guide the clinician to treatment include active caries, biting pain, and to a lesser degree, having a crack detectable with an explorer, connecting with a restoration, or blocking transilluminated light; the main treatment chosen is a complete crown. Of those teeth treated (36%), few (14%) will need retreatment but will still survive, despite having an internal crack as well. CONCLUSIONS AND PRACTICAL IMPLICATIONS: Although cracked teeth often pose a dilemma to clinicians, clincians are generally good at deciding which teeth to treat and when and which to monitor.

Onset and resolution of pain among treated and untreated posterior teeth with a visible crack: Three-year findings from the national dental practice-based research network.

OBJECTIVE: Cracked teeth may be associated with pain, especially biting pain, and to a lesser degree cold and spontaneous pain.  Described are how commonly these pains remain constant, develop, or resolve over time, none of which have been well-described, especially among untreated cracked teeth. METHODS: Cracked teeth from the Cracked Tooth Registry (CTR) study were followed for 3 years.  Assessments of cold, biting, and spontaneous pain and treatments performed were completed at enrollment (Y0) and at each annual recall visit. RESULTS: 209 practitioners enrolled 2,858 patients, each with a visible crack on a posterior tooth; 2601 (91%) patients attended at least one recall visit. Overall, 960 (37%) were treated, primarily with crowns. Among both treated and untreated cracked teeth with biting pain or spontaneous pain at Y0, the vast majority (92-99%) had their pain resolved by the time of a recall visit and 85-93% remained pain-free after initial resolution. The observations for cold pain were similar: 68% (untreated) and 78% (treated) became free of cold pain at some point during follow-up, and 84% of these stayed free of cold pain after initial resolution. Few teeth developed biting or spontaneous pain (4-8%) and 44-67% of these had pain resolution during the follow-up period. CONCLUSION: In this study, treatment resolved a preponderance of pain associated with a cracked tooth.  Pain was also resolved for most untreated cracked teeth, especially biting pain, and to a lesser degree spontaneous and cold pain, although not to the same degree as with the treated cracked teeth.

Outcomes of treatment and monitoring of posterior teeth with cracks: three-year results from the National Dental Practice-Based Research Network.

OBJECTIVES: To describe treatment and monitoring outcomes of posterior teeth with cracks at baseline followed in the National Dental Practice-Based Research Network for up to three years. MATERIALS AND METHODS: Two hundred and nine dentists enrolled a convenience sample of 2,858 patients, each with a posterior tooth with at least one visible crack and followed them for three years. Characteristics at the patient, tooth, and crack level were recorded at baseline and at annual recall visits. Data on all teeth referred for extraction were reviewed. Data on all other teeth, treated or monitored, seen at one or more recall visits were reviewed for evidence of failure (subsequent extraction, endodontics, or recommendation for a re-treatment). RESULTS: The survival rate for teeth with cracks at baseline exceeded 98% (only 37 extractions), and the failure rate for teeth that were treated restoratively was only 14%. Also, only about 14% of teeth recommended at baseline for monitoring were later recommended to be treated, and about 6.5% of teeth recommended for monitoring at baseline were later treated without a specific recommendation. Thus, about 80% of teeth recommended at baseline for monitoring continued with a monitoring recommendation throughout the entire three years of the study. Treatment failures were associated with intracoronal restorations (vs. full or partial coverage) and male patients. CONCLUSIONS: In this large 3-year practice-based study conducted across the USA, the survival rate of posterior teeth with a visible crack exceeded 85%. Clinical relevance Dentists can effectively evaluate patient-, tooth-, and crack-level characteristics to determine which teeth with cracks warrant treatment and which only warrant monitoring.

Baseline characteristics as 3-year predictors of tooth fracture and crack progression: Findings from The National Dental Practice-Based Research Network.

BACKGROUND: The authors of this practice-based study estimated the risk of experiencing tooth fractures and crack progression over 3 years and correlated baseline patient-, tooth-, and crack-level characteristics with these outcomes. METHODS: Two-hundred-and-nine National Dental Practice-Based Research Network dentists enrolled a convenience sample of 2,601 participants with a cracked vital posterior tooth that had been examined for at least 1 recall visit over 3 years. Data were collected at the patient, tooth, and crack levels at baseline, annual follow-up visits, and any interim visits. Associations between these characteristics and the subsequent same-tooth fractures and crack progression were quantified. RESULTS: Of the 2,601 teeth with a crack or cracks at baseline, 78 (3.0%; 95% confidence interval, 2.4% to 3.7%) subsequently developed a fracture. Of the 1,889 patients untreated before year 1, 232 (12.3%; 95% confidence interval, 10.9% to 13.8%) had some type of crack progression. Baseline tooth-level characteristics associated with tooth fracture were the tooth was maxillary and had a wear facet through enamel and a crack was detectable with an explorer, on the facial surface, and in a horizontal direction. Crack progression was associated with males and teeth with multiple cracks at baseline; teeth with a baseline facial crack were less likely to show crack progression. There was no commonality between characteristics associated with tooth fracture and those associated with crack progression. CONCLUSIONS: Development of tooth fractures and crack progression over 3 years were rare occurrences. Specific characteristics were associated with the development of tooth fracture and crack progression, although none were common to both. PRACTICAL IMPLICATIONS: This information can aid dentists in assessing factors that place posterior cracked teeth at risk of experiencing adverse outcomes.

Symptom changes and crack progression in untreated cracked teeth: One-year findings from the National Dental Practice-Based Research Network.

OBJECTIVES: The study objective was to: (1) quantify symptom (pain) and crack changes during one year of follow-up, among teeth that had at least one visible crack at baseline but which did not receive treatment for those cracks; (2) identify any patient traits/behaviors and external tooth/crack characteristics correlated with these changes. METHODS: In this observational study, 209 National Dental Practice-Based Research Network dentists enrolled a convenience sample of 2858 subjects, each with a single, vital posterior tooth with at least one observed external crack; 1850 teeth remained untreated after one year of follow-up and were the cohort for analyses. Data were collected at the patient-, tooth-, and crack-level at baseline, one-year follow up (Y1), and interim visits. Associations between changes in symptoms and cracks were identified, as were changes in symptoms associated with baseline treatment recommendations. RESULTS: Changes in pain symptoms were observed in 32% of patients; decreases were twice as common as increases (23% vs. 10%). More changes were observed in cold pain than in biting pain and spontaneous pain combined; 2% had increases in biting pain and 2% in spontaneous pain. Only 6% had an increase in the number of cracks. Changes in pain symptoms were not associated with an increase in the number of cracks, but were associated with baseline treatment recommendations. Specifically, pain symptom changes (especially decreases) were more common when the tooth was recommended for treatment at baseline. CONCLUSIONS: Cracked teeth that have not received treatment one year after baseline do not show meaningful progression as measured by increased symptoms or number of cracks during follow-up. CLINICAL SIGNIFICANCE: Untreated cracked teeth, most of which were recommended for monitoring at baseline and some of which were recommended for treatment but did not receive treatment, remained relatively stable for one year with little progression of cracks or symptoms.

Recommended treatment of cracked teeth: Results from the National Dental Practice-Based Research Network.

STATEMENT OF PROBLEM: Despite the high prevalence of posterior cracked teeth, questions remain regarding the best course of action for managing these teeth. PURPOSE: The purpose of this clinical study was to identify and quantify the characteristics of visible cracks in posterior teeth and their association with treatment recommendations among patients in the National Dental Practice-Based Research Network. MATERIAL AND METHODS: Network dentists enrolled patients with a single, vital posterior tooth with at least 1 observable external crack. Data were collected at the patient, tooth, and crack levels, including the presence and type of pain and treatment recommendations for subject teeth. Frequencies according to treatment recommendation were obtained, and odds ratios (ORs) comparing recommendations for the tooth to be restored versus monitored were calculated. Stepwise regressions were performed using generalized models to adjust for clustering; characteristics with P<.05 were retained. RESULTS: A total of 209 dentists enrolled 2858 patients with a posterior tooth with at least 1 crack. Mean ±standard deviation patient age was 54 ±12 years; 1813 (63%) were female, 2394 (85%) were non-Hispanic white, 2213 (77%) had some dental insurance, and 2432 (86%) had some college education. Overall, 1297 (46%) teeth caused 1 or more of the following types of pain: 1055 sensitivity to cold, 459 biting, and 367 spontaneous. A total of 1040 teeth were recommended for 1 or more treatments: restoration (n=1018; 98%), endodontics (n=29; 3%), endodontic treatment and restoration (n=20; 2%), extraction (n=2; 0.2%), and noninvasive treatment, for example, occlusal device, desensitizing (n=11; 1%). The presence of caries (OR=67.3), biting pain (OR=7.3), and evidence of a crack on radiographs (OR=5.0) were associated with over 5-fold odds of recommending restoration. Spontaneous pain was associated with nearly 3-fold odds; pain to cold, having dental insurance, a crack that was detectable with an explorer or blocked transilluminated light, or connected with a restoration were each weakly associated with increased odds of recommending a restoration (OR<2.0). CONCLUSIONS: Approximately one-third of cracked teeth were recommended for restoration. The presence of caries, biting pain, and evidence of a crack on a radiograph were strong predictors of recommending a restoration, although the evidence of a crack on a radiograph only accounted for a 3% absolute difference (4% recommended treatment versus 1% recommended monitoring).

Observable characteristics coincident with internal cracks in teeth: Findings from The National Dental Practice-Based Research Network.

BACKGROUND: This study determined if there are observable patient-, tooth- and crack-level characteristics markedly associated with whether a tooth with an external crack also has an internal crack. METHODS: Two hundred nine dentists in The National Dental Practice-Based Research Network enrolled 2,858 adults with a vital permanent posterior tooth having at least 1 observed external crack. Presence and characteristics of internal cracks were recorded for 435 cracked teeth that were treated. Generalized estimating equations were used to identify significant (P < .05) independent odds ratios associated with the tooth having internal cracks. RESULTS: Overall, 389 teeth (89%) had at least 1 internal crack, with 46% of these teeth having 2 or more internal cracks. Sixty-nine percent of treated cracked teeth were associated with 1 or more types of pain assessed before treatment; 53% were associated with cold testing, 37% with bite testing, and 26% with spontaneous pain. In the final model, biting pain, having an external crack that connected with a restoration, or an external crack that extended onto the root was each associated with more than a 2-fold increased odds of having an internal crack. CONCLUSIONS: Essentially 9 of 10 teeth that had at least 1 external crack also had at least 1 internal crack. PRACTICAL IMPLICATIONS: The external cracks that a dental practitioner should be most concerned about, because they are most likely to be associated with internal cracks in the tooth, are those in which the patient experiences biting pain, is connected with a restoration of some type, or extends onto the root.

Associations of types of pain with crack-level, tooth-level and patient-level characteristics in posterior teeth with visible cracks: Findings from the National Dental Practice-Based Research Network.

OBJECTIVES: The objective of this study was to determine which patient traits, behaviors, external tooth and/or crack characteristics correlate with the types of symptoms that teeth with visible cracks exhibit, namely pain on biting, pain due to cold stimuli, or spontaneous pain. METHODS: Dentists in the National Dental Practice-Based Research Network enrolled a convenience sample of subjects each of whom had a single, vital posterior tooth with at least one observable external crack (cracked teeth); 2858 cracked teeth from 209 practitioners were enrolled. Data were collected at the patient-, tooth-, and crack-level. Generalized estimating equations were used to obtain significant (p < .05) independent odds ratios (OR) associated with teeth that were painful for 10 outcomes based on types of pain and combinations thereof. RESULTS: Overall, 45% of cracked teeth had one or more symptoms. Pain to cold was the most common symptom, which occurred in 37% of cracked teeth. Pain on biting (16%) and spontaneous pain (11%) were less common. Sixty-five percent of symptomatic cracked teeth had only one type of symptom, of these 78% were painful only to cold. No patient-, tooth- or crack-level characteristic was significantly associated with pain to cold alone. Positive associations for various combinations of pain symptoms were present with cracks that: (1) were on molars; (2) were in occlusion; (3) had a wear facet through enamel; (4) had caries; (5) were evident on a radiograph; (6) ran in more than one direction; (7) blocked transilluminated light; (8) connected with another crack; (9) extended onto the root; (10) extended in more than one direction; or (11) were on the distal surface. Persons who were <65 yo or who clench, grind, or press their teeth together also were more likely to have pain symptoms. Pain was less likely in teeth with stained cracks or exposed roots, or in non-Hispanic whites. CONCLUSIONS: Although pain to cold was the most commonly noted pain associated with symptomatic cracked teeth, no patient-, tooth- or crack-level characteristic was significantly associated with pain to cold alone. Characteristics were only associated with pain on biting and/or spontaneous pain with or without pain to cold. CLINICAL SIGNIFICANCE: Although often considered the most reliable diagnosis for a cracked tooth, pain on biting is not the most common symptom of a tooth with a visible crack, but rather pain to cold.

Correlation between symptoms and external characteristics of cracked teeth: Findings from The National Dental Practice-Based Research Network.

BACKGROUND: Cracked teeth are ubiquitous in the adult dentition. The objective of this study was to determine which patient traits and behaviors and external tooth and crack characteristics correlate with cracked teeth being symptomatic. METHODS: Dentists in The National Dental Practice-Based Research Network enrolled a convenience sample of patients each with a single, vital posterior tooth with at least 1 observable external crack in this observational study; they enrolled 2,975 cracked teeth from 209 practitioners. The authors collected data at the patient level, tooth level, and crack level. They used generalized estimating equations to obtain significant (P < .05) independent odds ratios (OR) associated with teeth that were symptomatic for a crack. RESULTS: Characteristics positively associated with cracked tooth symptoms, after adjusting for demographics, included patients who clenched, ground, or pressed their teeth together (OR, 1.30; 95% confidence interval [CI], 1.12-1.50), molars (OR, 1.58; 95% CI, 1.30-1.92), teeth with a wear facet through enamel (OR, 1.22; 95% CI, 1.01-1.40), carious lesions (OR, 1.31; 95% CI, 1.07-1.60), cracks that were on the distal surface of the tooth (OR, 1.31; 95% CI, 1.13-1.52), and cracks that blocked transilluminated light (OR, 1.31, 95% CI, 1.09-1.57). Teeth with stained cracks were negatively associated with having cracked tooth symptoms (OR, 0.68; 95% CI, 0.55-0.84). CONCLUSIONS: The greatest likelihood of a cracked tooth being symptomatic was found when patients reported clenching or grinding their teeth and had a molar with a distal crack that blocked transilluminated light. PRACTICAL IMPLICATIONS: This information can help inform dentists in the decision-making process regarding the prognosis for a cracked tooth.

Polymerization stress--is it clinically meaningful?

OBJECTIVES: The objective of this article is to discuss the evidence for polymerization shrinkage and shrinkage stress of dental composite restoratives in terms of its potential relevance to the clinical situation METHODS: Articles relating to the issue of polymerization contraction stress generation in dental composite materials, and the factors that influence it, were reviewed and included. Particular attention was paid to evidence derived from clinical studies. Articles were identified through PubMed and through the bibliographies of other articles. RESULTS: There is extensive evidence for the presence of polymerization contraction stress in dental composites, as well as evidence for its deleterious effects, which include marginal leakage, gap formation, cuspal deflection, tooth cracking, reduced bond strength and lowered mechanical properties of the restorative. There is little, if any, direct evidence for the clinical effect of these contraction stresses. No study has directly established a link between these stresses and enhanced postoperative sensitivity or recurrent caries, for example. However, the concern over these stresses and the manner in which they influence the placement of current composite materials demonstrates that they are considered to be very important. CONCLUSION: Though no direct evidence exists to prove that the generation of contraction stress in dental composite restorations causes reduced clinical longevity, the indirect evidence from numerous in vitro studies and the concern over controlling their effects proves that they are clinically relevant.

Concordance between clinical practice and published evidence: findings from The National Dental Practice-Based Research Network.

BACKGROUND: Documenting the gap between what is occurring in clinical practice and what published research findings suggest should be happening is an important step toward improving care. The authors conducted a study to quantify the concordance between clinical practice and published evidence across preventive, diagnostic and treatment procedures among a sample of dentists in The National Dental Practice-Based Research Network ("the network"). METHODS: Network dentists completed one questionnaire about their demographic characteristics and another about how they treat patients across 12 scenarios/clinical practice behaviors. The authors coded responses to each scenario/clinical practice behavior as consistent ("1") or inconsistent ("0") with published evidence, summed the coded responses and divided the sum by the number of total responses to create an overall concordance score. The overall concordance score was calculated as the mean percentage of responses that were consistent with published evidence. RESULTS: The authors limited analyses to participants in the United States (N = 591). The study results show a mean concordance at the practitioner level of 62 percent (SD = 18 percent); procedure-specific concordance ranged from 8 to 100 percent. Affiliation with a large group practice, being a female practitioner and having received a dental degree before 1990 were independently associated with high concordance (≥ 75 percent). CONCLUSION: Dentists reported a medium-range concordance between practice and published evidence. PRACTICAL IMPLICATIONS: Efforts to bring research findings into routine practice are needed.

Information-seeking behaviors of dental practitioners in three practice-based research networks.

Research on the information-seeking behaviors of dental practitioners is scarce. Knowledge of dentists' informationseeking behaviors should advance the translational gap between clinical dental research and dental practice. A cross-sectional survey was conducted to examine the self-reported information-seeking behaviors of dentists in three dental practice-based research networks (PBRNs). A total of 950 dentists (65 percent response rate) completed the survey. Dental journals and continuing dental education (CDE) sources used and their influence on practice guidance were assessed. PBRN participation level and years since dental degree were measured. Full-participant dentists reported reading the Journal of the American Dental Association and General Dentistry more frequently than did their reference counterparts. Printed journals were preferred by most dentists. A lower proportion of full participants obtained their CDE credits at dental meetings compared to partial participants. Experienced dentists read other dental information sources more frequently than did less experienced dentists. Practitioners involved in a PBRN differed in their approaches to accessing information sources. Peer-reviewed sources were more frequently used by full participants and dentists with fifteen years of experience or more. Dental PBRNs potentially play a significant role in the dissemination of evidence-based information. This study found that specific educational sources might increase and disseminate knowledge among dentists.

Critical appraisal: preheating composites.

Resin composite is the most commonly used material for direct placement restorations. In particular, composite is now used more frequently than amalgam for direct posterior restorations. However, resin composite still suffers from some disadvantages, including the use of an adhesive interfacial bond that degrades with time, moisture, and function in the mouth, and certain key mechanical properties (e.g., modulus of elasticity) that are inferior to those of amalgam. As such, there is a concern that the resin composite should be inserted into a preparation with as few voids as possible to enhance interfacial adaptation, and maximizing the composite degree of conversion so as to maximize mechanical properties. The use of preheated composite has been suggested to aid in both of these goals. This Critical Appraisal looks at evidence in the peer-reviewed scientific literature that examines the value of inserting warm composite into cavity preparations.

Association between caries location and restorative material treatment provided.

OBJECTIVES: This cross-sectional study by the Northwest PRECEDENT practitioners correlated the location of caries diagnosed in the past 12 months with treatment provided. METHODS: An oral health survey was conducted on up to 20 patients per practice for 101 practises in the Northwest PRECEDENT network. A total of 1943 eligible patients were randomly assessed for the location of and treatment provided for caries lesions diagnosed within the past 12 months. Regression analysis using generalized estimating equations (GEE) was performed to assess association of treatment to tooth location and surface characterization, adjusting for age, practice location (urban/rural), dentist gender, and experience level. The analysis accounts for clustering by practice using robust variance estimates. RESULTS: Overall, 55.4% of patients exhibited recent caries and 42.8% received treatment for at least one permanent tooth. 18% of treated teeth were treated with amalgam, and 72% were treated with composite. This percentage varied as a function of tooth surface characteristics, patient characteristics, and dentist characteristics. The results suggest that restoration selection does depend on tooth type and which surfaces are being restored. The odds of a molar receiving an amalgam restoration are 2.44 (95% CI=1.81-3.30) times higher as compared to a bicuspid, adjusting for all other covariates. When the restoration includes the occlusal surface of a tooth the odds are 0.42 (95% CI=0.20-0.89) times as great that amalgam will be placed. When the restoration includes the mesial or distal surface of the tooth the odds for amalgam restoration are 2.49 (95% CI=1.25-4.95) times higher compared to when it does not include these surfaces. CONCLUSION: Restorative material choice varied based on caries location and practitioner gender.

Unmet dental needs in rural primary care: a clinic-, community-, and practice-based research network collaborative.

BACKGROUND: Oral health is an essential component of general health and well-being, yet barriers to the access of dental care and unmet needs are pronounced, particularly in rural areas. Despite associations with systemic health, few studies have assessed unmet dental needs across the lifespan as they present in primary care. This study describes the prevalence of oral health conditions and unmet dental needs among patients presenting for routine care in a rural Oregon family medicine practice. METHODS: Eight primary care clinicians were trained to conduct basic oral health screenings for 7 dental conditions associated with International Statistical Classification of Diseases and Related Health Problems 9-Clinical Modification codes. During the 6-week study period, patients older than 12 months of age who presented to the practice for a regularly scheduled appointment received the screening and completed a brief dental access survey. RESULTS: Of 1655 eligible patients, 40.7% (n = 674) received the screening and 66.9% (n = 1108) completed the survey. Half of the patients who were screened (46.0%, n = 310) had oral health conditions detected, including partial edentulism (24.5%), dental caries (12.9%), complete edentulism (9.9%), and cracked teeth (8.9%). Twenty-eight percent of the patients reported experiencing unmet dental needs. Patients with dental insurance were significantly more likely to report better oral and general health outcomes as compared with those who had no insurance or health insurance only. CONCLUSIONS: Oral health diseases and unmet dental needs presented substantially in patients with ages ranging across the lifespan from one rural primary care practice. Primary care settings may present opportune environments for reaching patients who are unable to obtain regular dental care.

Cracked teeth: a review of the literature.

Although cracked teeth are a common problem for patients and dentists, there is a dearth of evidence-based guidelines on how to prevent, diagnose, and treat cracks in teeth. The purpose of this article is to review the literature to establish what evidence exists regarding the risk factors for cracked teeth and their prevention, diagnosis, and treatment.