Abstract
Objectives
To (1) determine whether dentists in Dental Practice-based Research Network practices are more likely to repair versus replace a restoration that they diagnose as defective; (2) quantify the specific reasons for repairing or replacing; and (3) test the hypothesis that certain dentist, patient, and restoration-related variables are associated with the decision to repair versus replace.
Methods
This cross-sectional study used a consecutive patient/restoration recruitment design. Practitioner-investigators recorded data on consecutive restorations in permanent teeth that needed repair or replacement. DPBRN is a consortium of participating practices and dental organizations in the United States and Scandinavia. Data included the primary reason for repair or replacement, tooth surface(s) involved, restoration materials used, and patient demographics.
Results
Data for 9,484 restorations were collected from 7,502 patients in 197 practices. 75% (7,073) of restorations were replaced and 25% (2,411) repaired. Secondary caries was the main reason (43%, n=4,124) for treatment. Factors associated with greater likelihood of repair versus replace (p<.05) included: fewer years since dental school graduation, practicing in a solo or small group practice, being the dentist who placed the original restoration, older patient age, original restorative material was not amalgam, restoration of a molar, and fewer surfaces in the old restoration.
Conclusion
DPBRN dentists were more likely to replace than repair. Secondary caries was the most common reason for repairing or replacing existing restorations. Certain dentist, patient, and restoration-related variables were associated with the repair versus replace decision.
Keywords: practice-based research, repair, replacement, decision, defective, restorations
Introduction
Approximately half of all restorations placed in general dental practice are done to replace a defective or failed restoration (Jokstad et al., 1994; Pink et al., 1994; Mjör and Moorhead, 2000, McDaniel et al., 2000). The reasons that restorations are replaced may be divided into three major categories (Hickel and Manhart, 2001): clinician factors, material properties, and patient factors. Irrespective of how the reason is categorized, it is often difficult to identify which factor plays the most important role in the failure. Sometimes a combination of factors may be the cause of the failure, although clinicians rarely record more than one reason for replacement of restorations. Most failures occur gradually, but abrupt failures can also occur, e.g., bulk fracture. The recognition of defects does not necessarily coincide with the failure of restorations to an extent that it requires immediate replacement of the restoration. Because defects can develop gradually, this may provide an opportunity to do minimally invasive treatment, rather than replacing the entire restoration. This minimally invasive treatment may include repair or refurbishing a defect (Mjör, 1993; Gordan, 2000; 2001; Gordan et al., 2002; Gordan et al., 2003; Blum et al., 2003; Gordan et al., 2009; Gordan et al., 2011), especially if the defect is localized and accessible. A better understanding of dentist and patient characteristics that are associated with the decision to repair or replace defective restorations may assist with the development of guidelines to improve treatment of existing restorations. Therefore, the purpose of this study is to: (1) determine whether dentists in DPBRN (The Dental Practice-Based Research Network) practices are more likely to repair versus replace a restoration that they diagnose as defective; (2) quantify the specific reasons for repairing or replacing; and (3) test the hypothesis that certain dentist, patient, and restoration-related variables are associated with the decision to repair versus replace.
Materials and Methods
Selection and recruitment process
The study design was cross-sectional. A total of 197 practitioner-investigators participating in the DPBRN were enrolled in this study and recorded data on consecutive defective restorations that needed repair or replacement on permanent teeth. The DPBRN comprises outpatient dental practices mainly from five regions: AL/MS: Alabama/Mississippi; FL/GA: Florida/Georgia; MN: dentists employed by HealthPartners and community practitioners in Minnesota; PDA: Permanente Dental Associates in cooperation with Kaiser Permanente Center for Health Research, Portland, Oregon; and SK: Denmark, Norway, and Sweden. Practice structures differed by DPBRN region. Dentists from the AL/MS and FL/GA regions were primarily in independent or small group practices, MN and PDA dentists were primarily in large group practices, and SK dentists were in public or private health care settings. This study was approved by the respective Institutional Review Board of the participating regions.
DPBRN practitioner-investigators were recruited through continuing education courses and/or mass mailings to licensed dentists within the participating regions. As part of the eligibility criteria, all dentists completed (1) an Enrollment Questionnaire describing their demographic and practice characteristics and certain personal characteristics, (2) an Assessment of Caries Diagnosis and Caries Treatment questionnaire, (3) training in human subjects protection, and (4) attended a DPBRN orientation session or viewed a video version of it. Copies of the questionnaires and summary data for dentists’ demographic and practice characteristics are available at http://www.dentalpbrn.org/users/publications/Supplement.aspx.
This study used a consecutive patient/restoration recruitment design (http://www.dentalpbrn.org/uploadeddocs/Study5.Consecutive%20Patient%20Log.pdf). Once the study was started, every patient who received a repair or replacement of a restoration on a permanent tooth was asked to participate. Patients who returned for additional appointments while data collection was still ongoing were not eligible for further data collection. Only restorations eligible during the first appointment were enrolled and a maximum of four eligible restorations per patient during that first appointment were included. A consecutive patient/restoration log form was used to record information on eligible restorations whether or not the patient participated in the study. All the data collection forms used for this study are available at http://www.DentalPBRN.org/users/publications/Supplement.aspx.
Variable selection
Restoration replacement was defined as the entire removal of the existing defective/failed restoration and any adjacent pathologically altered and discolored tooth tissue that was esthetically or functionally unacceptable.
Repair was defined as the removal of part of the existing restoration and any adjacent pathologically altered as well as discolored tooth tissue that was esthetically or functionally unacceptable followed by placement of restorative material in the prepared site. Repair also included light grinding and polishing, removal of overhangs, polishing discolored tooth-colored restorations, or sealing margins.
Practitioner-investigators collected data for each enrolled restoration that needed repair or replacement on permanent tooth surfaces. Data collected included: (1) the main reason for repair or replacement of the restoration (see, http://www.dentalpbrn.org/uploadeddocs/Study%205_table.pdf); (2) tooth type and tooth surfaces being restored; and (3) the restorative materials used for the old and the new restoration. Dentists diagnosed the need to repair or replace the existing restoration based on the diagnostic methods they typically use in their practice, which consist mainly of visual-tactile in association with radiographic examinations.
Restorative materials were classified as amalgam, direct tooth colored restorations (resin-based composite [RBC], compomer, and glass ionomer), indirect restorations (indirect RBC, ceramic, and porcelain fused to metal), and gold or any other metal casting. When multiple materials were reported, the material most likely to fail was used for classification. Information about gender, age, race, ethnicity, and insurance coverage of enrolled patients were also recorded.
The Data Collection Form was pre-tested by sixteen practitioner-investigator members of the DPBRN. Pre-testing consisted of assessing the feasibility of the form in the flow of a busy practice environment, as well as the comprehension and intuitiveness of the classification criteria. The pre-testing phase for each of these groups met a test-retest reliability of kappa > 0.70 or ICC > 0.70.
Statistical analysis
Descriptive statistics were calculated for dentist, patient, and restoration variables. Frequencies were examined crossing the repair/replacement variable with characteristics of the defective restoration. A binary logistic model, with Generalized Estimating Equations to adjust for clustering within dental practices and restorations within patients, was used to examine dentist, patient, and restoration variables as predictors of the decision to repair or replace the restoration. A backward elimination approach was used that removed the least significant index variable from the model in subsequent steps until all remaining variables were significant using p < 0.15 for retention (Menard, 1995), all two-way interactions were tested.
Dentists associated with PDA or HealthPartners were categorized as large group practice model (LGP). Other practices were assigned by regional coordinators to the categories of solo or small group private practices defined as 3 or less dentists in the practice (SGP) or public health practice (PHP). Type of practice (PHP/LGP = 0, SGP = 1); Dentist and patient gender (male = 0, female = 1); dental insurance (no = 0, yes = 1); study dentist placed the original restoration (no= 0, yes = 1), tooth type (molar = 0, premolar or anterior = 1), number of surfaces in original restoration (one, two, three or more = 1, 2, 3), material (amalgam = 0, direct tooth colored/ indirect tooth colored/ gold =1) were coded as indicated. An alpha level of .05 was used as the level for statistical significance.
Results
Data about 9,875 restorations were collected from 7,502 patients. The mean (S.D.) number of restorations per dentist was 50 (16). For 391 of the restorations, either a temporary restoration was placed (n = 254) or the dentist failed to indicate whether the procedure was a repair or replacement (n = 137). Those restorations were excluded from all subsequent analyses; therefore this study reports data from 9,484 restorations of which 75% (7,073) were replaced and 25% (2,411) were repaired.
A summary of the main reason for failure of existing restorations, by whether the restoration was repaired or replaced, is presented in Table 1 together with other descriptive data for restoration characteristics. Existing restorations with the diagnosis of secondary caries accounted for 43% of all treatments and received the highest number of repair treatments (30%). The variable for “main reason for the repair or replacement” was dummy-coded and tested using secondary caries as the reference (most common to be repaired). Fracture/bulk fracture/missing (OR = 0.70, p < 001), pain sensitivity (OR = 0.13, p =.001), and discolored restoration (OR = 0.48, p = .020) were significantly less likely to be repaired than when secondary caries was the primary reason given for the treatment.
Table 1.
Characteristics of the 9,484 defective restorations that were either repaired or replaced
| Repair % (n) | Replacement % (n) | |
|---|---|---|
| Total restorations | 25% (2,411) | 75% (7,073) |
| Who placed the original restoration | ||
| - The same dentist | 32% (753) | 68% (1612) |
| - Another dentist | 23% (1596) | 77% (5292) |
| Missing information (n=231) | ||
| Practice Model | ||
| SGP | 22% (1279) | 78% (4448 |
| LGP | 30% (994) | 70% (2311) |
| PHP | 31% (138) | 69% (314) |
| Percent of practice time spent doing non-implant restorative dentistry | ||
| 0-20% | 24% (93) | 76% (297) |
| 21-40% | 30% (969) | 70% (1097) |
| 41-60% | 28% (469) | 72% (2264) |
| 61-80% | 22% (641) | 78% (2239) |
| 81-100% | 19% (167) | 81% (731) |
| Missing information (n=610) | ||
| Decade of dental school graduation | ||
| - 1979 or before | 20% (518) | 80% (2061) |
| - 1980-1989 | 27% (1013) | 73% (2785) |
| - 1990-1999 | 27% (408) | 73% (1084) |
| - 2000-2008 | 29% (472) | 71% (1143) |
| Tooth | ||
| Molar | 28% (1430) | 72% (3660) |
| Molar single surface | 24% (307) | 76% (991) |
| Molar two surfaces | 25% (417) | 75% (1270) |
| Molar three or more surfaces | 33% (667) | 67% (1369) |
| Pre Molar | 19% (454) | 81% (1983) |
| Pre molar single surface | 25% (97) | 75% (297) |
| Pre molar two surfaces | 13% (140) | 87% (902) |
| Pre molar three or more surfaces | 21% (205) | 79% (763) |
| Anterior | 26% (500) | 74% (1410) |
| Anterior single surface | 24% (121) | 76% (381) |
| Anterior two surfaces | 21% (118) | 79% (446) |
| Anterior three or more surfaces | 31% (251) | 69% (570) |
| Missing information (n=47) | ||
| Original material | ||
| Amalgam | 20% (1031) | 80% (4079) |
| Direct tooth colored | 30% (1012) | 70% (2330) |
| Indirect tooth colored | 39% (195) | 61% (310) |
| Gold | 55% (116) | 45% (90) |
| Missing information (n=316) | ||
| Reason for repair or replacement | ||
| Secondary/recurrent caries | 30% (1231) | 70% (2893) |
| Fracture/bulk fracture/missing | 23% (767) | 77% (2580) |
| Other | 23% (152) | 77% (523) |
| Degraded/ditched | 24% (169) | 76% (540) |
| Margins or restoration discolored | 17% (47) | 83% (232) |
| Patient request | 14% (25) | 86% (160) |
| Pain sensitivity | 5% (5) | 95% (92) |
| Missing information (n=68) |
Note: frequencies under tooth × surface are less than for each tooth category because of 122 cases of missing data for the surface variable.
Practice and patient characteristics are presented in Table 2. Patients were treated by 197 practices distributed across the DPBRN regions as AL/MS = 39, FL/GA = 44, PDA = 40, MN = 36, SK = 38. One hundred thirty-eight (70%) providers were male and 59 (30%) were female. Mean number of years since dental school graduation was 21.7 (SD = 10.5). The average percent of time that the dentist reports spending doing non-implant restorations was 56 (SD = 20). Regarding patient characteristics, 57% were female and 43% were males, 21% had dental insurance (n = 1,601). Patient race (this was self-reported by the patient) was White, 89%; Black or African American, 6%; Asian, 1%; American Indian or Alaskan native, < 1%; and other, 1%.
Table 2.
Summary of dentists’ and patients’ characteristics
| Variable | Mean (SD) or % (n) |
|---|---|
| Dentist's characteristics (n=197) | |
| Gender (male) | 70% (138) |
| Years since dental school graduation | 21.7 (SD=10.5) |
| Full-time (32+ hours per week in patient care) | 86% (162) |
| Dental chairs per office | 4.0 (SD=2.3) |
| Practice type | |
| - Solo or small group private practice | 58% (114) |
| - Large group practice | 37% (72) |
| - Public health service | 6% (11) |
| Percent of revenue derived from dental insurance | 58% (SD=32) |
| Percent of time spent on non-implant restorative care | 56% (SD=20) |
| Days wait for new patient examination appointment | 16.4 (SD=19.8) |
| Days wait for a treatment procedure appointment | 12.6 (SD=10.4) |
| Patient's characteristics (n=7,502) | |
| Patient gender (female) | 57% (4300) |
| Patient age | 51.4 (SD=16.0) |
| Hispanic ethnicity (missing=137) | 14% (737) |
| Race (missing=117) | |
| - White | 89% (6661) |
| - Black | 6% (450) |
| - Asian | 1% (105) |
| - American Indian or Alaskan native | <1% (62) |
| - Other | 1% (107) |
| Number of restorations | |
| Single restoration | 76% (5712) |
| Two restorations | 18% (1333) |
| Three restorations | 3% (331) |
| Four restorations | 2% (126) |
| Dental insurance or any third party coverage | 21% (1601) |
Table 3 presents the coefficients and odd ratios for dentist, patient, and restoration factors. Logistic regression indicated that of the dentist and patient characteristics; fewer years since dental school graduation (OR = 0.84, p <.001), practicing in a LGP compared to SGP (OR = 1.47, p< .001) and PHP (OR = 1.30, p = .047), having been the dentist who placed the original restoration (OR = 1.49, p < .001) and older age for the patient (OR = 1.24, p < .001), were significantly associated with a higher likelihood that the restoration was repaired instead of replaced. There were no differences for dentist's gender, full-time vs. part-time practice, days a patient waits for a treatment visit or a new patient examination visit, patient's gender, having private dental insurance, or the number of restorations treated during the visit.
Table 3.
Dentist, patient, and restoration characteristics associated with the decision to repair or replace a defective restoration
| Predictor variable (reference, if categorical) | B (SE) | OR (95% CI) | p. value |
|---|---|---|---|
| Dentist characteristics | |||
| Dentist gender (male) | n.s. | ||
| Time since graduation in decades | -.178 (.030) | 0.84 (0.79-0.89) | <.001 |
| Full/part time (full-time) | n.s. | ||
| Days wait for treatment visit | n.s. | ||
| Days wait for a new patient examination visit | n.s. | ||
| Large group practice (Small group practice) | .388 (.067) | 1.47 (1.29-1.68) | <.001 |
| Public health service (Small group practice) | .266 (.133) | 1.30 (1.01-1.69) | .047 |
| Dentist placed existing restoration (no) | .400 (.067) | 1.49 (1.31-1.70) | <.001 |
| Patient characteristics | |||
| Age in decades | .215 (.019) | 1.24 (1.19-1.29) | <.001 |
| Patient gender (female) | n.s. | ||
| Dental insurance (yes) | n.s. | ||
| Restoration factors | |||
| Number of restorations treated | n.s. | ||
| Dam was used (yes) | n.s. | ||
| Original material direct tooth colored (amalgam) | .637 (.072) | 1.89 (1.64-2.18) | <.001 |
| Original material indirect tooth colored (amalgam) | 1.037 (.107) | 2.82 (2.29-3.47) | <.001 |
| Original material gold (amalgam) | 1.148 (.141) | 3.15 (2.39-4.15) | <.001 |
| Tooth – premolar (molar) | -.649 (.069) | 0.52 (0.46-0.60) | <.001 |
| Tooth – anterior (molar) | -.764 (.092) | 0.47 (0.39-0.56) | <.001 |
| Surfaces | -.917 (.037) | 0.40 (0.37-0.43) | <.001 |
General estimating equations were used to adjust for restorations clustered within dentists and patients.
Backwards deletion was used with .15 used as the removal criterion.
The dependent variable was coded 0=replaced, 1=repaired.
Metric variables were coded as follows:
Years since graduation; 1=2000-2008, 2=1990-1999, 3=1980-1989; 4=1979 or earlier
Patient age; 1=20 or less, 21, 2=21-30, 3=31-40, 4=41-50; 5=51-60; 6=61-70; 7=91-80, 8=81 or older
Tooth surfaces;1=1, 2=2, 3=3 or more
An odds ratio of greater than one represents the increase in the probability of restoration repair compared to a restoration replacement for the comparison group over the reference group (for categorical variables) or for a one unit increase in the value of an ordinal or interval level variable
A defective restoration in a molar was more likely to be replaced than a restoration in a premolar (OR = .052, p < .001) or an anterior tooth (OR = 0.47, P < .001). Compared to an amalgam, if the existing restoration was a direct tooth-colored material (OR = 2.82, P < .001), indirect tooth-colored material (OR = 1.89, p < .001), or gold material (OR = 3.15, p < .001), it was more likely to have been repaired instead of replaced. Also, the fewer the number of surfaces involved in the original restoration (OR = 0.40, p <.001), the higher the likelihood that the restoration was repaired instead of replaced.
Secondary analyses
All two-way interactions were tested with significance occurring for practice type by material used for the original restoration (LGP × direct tooth colored, p < .001; LGP x gold, p = .046; PHP x direct tooth colored = .008). The model was subsequently tested separately for each material, which revealed that LGP was more likely to repair than replace compared to SGP for amalgam (OR = 1.90, p < .001), indirect tooth-colored material (OR = 1.98, p = .048), and gold (OR = 3.48, p = .049) with no differences for direct tooth-colored restorations. PHP practices were more likely to repair than SGP dentists for direct tooth-colored materials (OR = 1.46, p = .027), with no differences for amalgam, indirect tooth-colored restorations, or gold. The repair/replace variable for each practice type is presented by material in Table 4.
Table 4.
Repair/replace variable for each practice model by material.
| Material | Practice model | Repair | Replacement |
|---|---|---|---|
| % (n) | % (n) | ||
| Amalgam | SGP | 16% (461) | 85% (2,522)a |
| LGP | 28% (532) | 72% (1,387)a | |
| PHP | 18% (38) | 82% (170) | |
| Direct tooth-colored material | SGP | 31% (663) | 69% (1,512)b |
| LGP | 27% (260) | 73% (688) | |
| PHP | 41% (89) | 59% (130)b | |
| Indirect tooth-colored material | SGP | 31% (115) | 69% (258)c |
| LGP | 63% (73) | 37% (43)c | |
| PHP | 44% (7) | 56% (9) | |
| Gold | SGP | 36% (33) | 64% (58)d |
| LGP | 70% (80) | 30% (34)d | |
| PHP | 50% (3) | 50% (3) |
Note: Pair-wise comparisons were made across practice model and within material to interpret the significant material × practice interactions. Similar superscripts indicate statistical differences between rows at p < .05.
Sample size for this table totals 9168 restoration because of 316 cases of missing data for the existing restoration material variable.
Small group practice (SGP), Large group practice (LGP), Public health practice (PHP)
Discussion
Consistent with previous studies (Mjor et al., 2000; Burke et al, 2001; Deligeori et al., 2001; Gordan et al., 2009a), dentists participating in the DPBRN showed a higher rate of replacement of restorations when compared to repair. Several dentist and restoration-related variables are associated with the decision to repair versus replace. The only patient variable associated with increased likelihood to repair was older age.
Restoration factors
Dentists were more likely to repair a restoration in a molar than they were in a premolar or anterior tooth. Similarly, teeth involving restorations with single surfaces were more likely to receive repair than teeth with multiple restoration surfaces. Molar teeth receive more occlusal stress and dentists may have hesitated to remove any additional tooth structure material as it would occur during a restoration replacement. On the other hand, when restorations involve multiple surfaces, it may require a significant change of the restoration and /or restorative material for additional strength. A primary reason for choosing the repair of a defective restorations is extended longevity of the restoration, which is a major component in estimates of the long-term cost of restorative treatment (Mjör, 1992), and will have an effect on the longevity of the dentition because successively replaced restorations become larger and larger with each replacement (Gordan, 2000; 2001; Gordan et al., 2002; Qvist, 2008).
Another factor to consider in the decision for a replacement over repair is that the use of amalgam as a restorative material has dropped in recent years (Sunnefårdh-Grönberg et al., 2009; Christensen, 1998; Ottenga and Mjor, 2007) and perhaps when faced with the decision to repair versus replace, dentists and patients may have opted to just remove the amalgam and have a new tooth colored restoration. Our data support this premise. Amalgam restorations can be repaired and several studies have reported on the clinical success of amalgam repair (Gordan et al., 2011; Moncada et al., 2008; Gordan et al., 2006).
Consistent with previous studies (Rytomaa at al., 1979; Merrett and Elderton, 1984; Bader et al., 1994; Bader and Shugars, 1993) secondary caries was the most common reason for repair and replacement of existing restorations in the current study. Since this study did not gather information on changes in diagnosis once the dentist removed the defective/failed part of the restoration (i.e., the diagnosis was done pre-operatively), it is important to recognize the possibility of misdiagnoses in the large number of clinically diagnosed secondary caries lesions. Secondary caries has been the major reason for replacement of restorations in adults ever since the early days of operative dentistry (Black, 1908), but its nature, diagnosis, possible prevention, and treatment have largely remained uninvestigated. The current study also showed that when all the reasons for treatment of defective restorations were studied, dentists were more likely to repair restorations with the pre-diagnosis of secondary caries than any other reason. Since the diagnosis of secondary caries has not been clearly defined (Mjör & Toffenetti, 2000; Mjör et al, 2000; Mjör et al., 2002), dentists might misdiagnose marginal defect and staining at the margins reported with the diagnosis of secondary caries. In that case, studies have reported success with the repair of restorations with marginal defects and staining of the margins (Gordan et al., 2006; Gordan et al., 2009; Moncada et al., 2009; Gordan et al., 2011).
Dentist factors
Conclusions about longevity of restorations might be strongly influenced by clinicians’ threshold for replacing restorations that they consider “defective”. If dentists have a low threshold for replacing a restoration, then naturally the age of restorations will be shorter. Several dentists’ characteristics seem to influence the decision to repair versus replace existing restorations. Consistent with studies completed over 20 year ago, dentists who did not place the original restoration were more likely to replace it than dentists who placed the original restoration (Elderton, 1977; Elderton and Nuttal, 1983; Davies, 1984; Boyd, 1989; Bader and Shugars, 1992). It is plausible that dentists may be more confident with their own work, and consequently assume that the defective restorations can be repaired. Conversely, when dealing with a defective restoration in a new patient, no baseline knowledge may be available for a proper prognosis of the restoration in question. Furthermore, when dealing with a new patient, it may be possible that the defective restoration might have been present for a significant amount of time and the actual condition may be worse than the one presented by a patient who comes otherwise regularly to the dental practice.
This study also suggests that dentists from large group practices and those working in a public health model are more likely to repair than to replace defective restorations than dentists in private practices. Another practice-based study, where the same group of dentists participated in a questionnaire inquiring about the diagnosis and treatment of existing restorations, showed that dentists who belonged to large group practice chose alternative treatments that were more conservative than restoration replacement (Gordan et al, 2009). Dentists participating in large group practices usually belong to an organization in which standardization of diagnosis and treatment of existing restorations might be more available and consistent. HealthPartners Dental Group, for example, has an evidence-based guideline for treatment of dental caries to assist the clinician with caries treatment, risk assessment, and preventive interventions (http://www.guidelines.gov/search/search.aspx?term=caries). The Permanente Dental Associates dental group also sets standards for treatment recommendations through evidence reviews conducted by a Clinical Effectiveness Committee composed of dentists from each clinic.
This study observed that the less time since graduation from dental school, the higher the probability that the dentist does repair versus replacement. In fact, dentists graduating in the decade of 2000 and later repaired 29.2% of the defective restorations they treated compared to 27.3% and 26.7% for the decades of 1990-1999 and 1980-1989 respectively, and 20% for graduates from 1979 or earlier. After examining the values for each decade, a quadratic term was added to the overall model and both the linear and quadratic terms were significant. Changes in the dental school curriculum may explain these findings: recently-graduated practitioners have been exposed in the dental school curriculum to topics that are relevant to repair/replacement decisions, such as levels of disease control (Clark and Mjör, 2001), more defined role for caries diagnosis and prevention (Ismail, 1997; Lundeen and Roberson, 1995), and the teaching of repair of restorations (Blum et al., 2003; Gordan et al, 2003).
Clinical implications
It is recognized that while a few restorations may fail immediately after they were placed, most restorations last for some time prior to failure. Thus, stages prior to complete failure of restorations may allow some clinical action to be instituted to prevent further damage. It is also possible that some defects may reach a certain stage that does not compromise the tooth and no further degradation will occur (Gordan et al., 2006; Moncada et al., 2009; Gordan et al., 2009, Gordan et al., 2011). Actions like repair, refurbishing and monitoring will, therefore, under well-defined conditions, be suggested as reliable alternative treatments to complete replacement of restorations that are failing. However, this study was observational in that clinicians selected what they determined was the most appropriate treatment for failed and failing restorations and we observed that 75% of the dentists chose the replacement of restorations over repair. Replacement of restorations still constitutes the majority of the work performed by general dentists in their practices (Mjor et al., 2000; Burke et al, 2001; Deligeori et al., 2001) and it has contributed to the perpetuation of the “cycle of re-restoration” (Brantley et al., 1995). Consequently, proper diagnosis and selection of minimally invasive treatment for an existing restoration are critical steps, which will invariably affect the longevity of the tooth.
Conclusion
- Secondary caries was the main reason for repairing or replacing existing restorations in DPBRN practices.
- Dentists were more likely to replace than to repair.
- Certain dentist, patient, and restoration related variables were associated with the decision to replace versus to repair.
Acknowledgments
This work was supported by National Institutes of Health grants U01-DE-16746 and U01-DE-16747. Opinions and assertions contained herein are those of the authors and are not to be construed as necessarily representing the views of the respective organizations or the National Institutes of Health. The informed consent of all human subjects who participated in this investigation was obtained after the nature of the procedures had been explained fully.
This work was supported by National Institutes of Health grants DE-16746, DE-16747, and DE-22516.
Footnotes
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
All authors conceived, designed, and implemented the project. All authors contributed to the interpretation of findings. All authors read and approved the final manuscript.
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