Laser light passage through restored and carious posterior teeth

Laser Doppler flowmetry (LDF) has been used to investigate pulpal blood flow as a means of pulp vitality testing. Transmission of laser light from the tooth surface to the pulp space may be influenced by caries and restorations. One hundred and twenty‐two first and second molars that had caries into dentine, restorations or significant loss of coronal tissue were sectioned in half axio‐bucco‐lingually. The two sections were illuminated with a laser from their buccal and lingual aspects 2 mm coronal to the amelocemental junction. Light reaching the pulp space was recorded. Buccal and lingual illumination sites were equally effective for 67 teeth (55%). Buccal sites alone were effective for 35 teeth (29%), despite over one‐third of these surfaces being restored or featuring enamel or dentine caries. A lingual position alone was effective for 20 teeth (16%). Caries affected light transmission, but for over half the teeth, the pulp could be illuminated from all four probe positions. No effect was found when the influence of mesial and distal restorations on transmission into the corresponding tooth section was examined. The pulp spaces of most (84%) restored, and carious posterior teeth could be illuminated by laser light from their buccal aspect and these teeth could potentially be vitality tested using LDF.     

Clinical performance of DIAGnodent in the detection of secondary carious lesions

The diagnostic value of DIAGNOdent in detecting primary occlusal caries has been investigated in many studies, although its use in in vivo detection of secondary caries remains unclear. The aim of this study was to investigate the ability of DIAGNOdent in in vivo detection of secondary caries on teeth with amalgam restorations. The material comprised 51 posterior teeth restored with amalgam material. Bitewing radiographs were taken of all teeth, in accordance with the standard clinical protocol, and analysed by five observers with respect to secondary caries. The restoration margins of each tooth were carefully scanned with DIAGNOdent and the site of the highest reading and its value were registered in a digital picture. The color (stained/unstained) of the restoration margins was also documented. The restoration material was removed and all cavities were examined carefully by two observers together, both visually and by probe. The results showed that the sensitivity and specificity of DIAGNOdent and conventional radiography in detecting secondary caries were 0.60/0.81 and 0.56/0.92, respectively. For DIAGNOdent, 100% of the teeth in the false-positive fraction had stains. Regarding receiver operating characteristic analyses, the Az values were 0.78 and 0.69 for DIAGNOdent and radiography, respectively. We conclude that DIAGNOdent may be used only as an adjunct to conventional methods in detecting secondary caries on teeth with amalgam restorations.     

Clinical performance of DIAGNOdent in the detection of secondary carious lesions

The diagnostic value of DIAGNOdent in detecting primary occlusal caries has been investigated in many studies, although its use in in vivo detection of secondary caries remains unclear. The aim of this study was to investigate the ability of DIAGNOdent in in vivo detection of secondary caries on teeth with amalgam restorations. The material comprised 51 posterior teeth restored with amalgam material. Bitewing radiographs were taken of all teeth, in accordance with the standard clinical protocol, and analysed by five observers with respect to secondary caries. The restoration margins of each tooth were carefully scanned with DIAGNOdent and the site of the highest reading and its value were registered in a digital picture. The color (stained/unstained) of the restoration margins was also documented. The restoration material was removed and all cavities were examined carefully by two observers together, both visually and by probe. The results showed that the sensitivity and specificity of DIAGNOdent and conventional radiography in detecting secondary caries were 0.60/0.81 and 0.56/0.92, respectively. For DIAGNOdent, 100% of the teeth in the false-positive fraction had stains. Regarding receiver operating characteristic analyses, the A_z values were 0.78 and 0.69 for DIAGNOdent and radiography, respectively. We conclude that DIAGNOdent may be used only as an adjunct to conventional methods in detecting secondary caries on teeth with amalgam restorations.     

Five-year study of Class II restorations in permanent teeth using amalgam, glass polyalkenoate (ionomer) cermet and resin-based composite materials

The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cermet material and a resin-based composite material used in small Class II cavities in permanent teeth. All restorations were inserted under rubber dam. They were examined yearly for 3 years. One clinician continued the study up to 5 years. The clinical examination focused on two criteria: clinically acceptable and failure. In addition, impressions were taken of the prepared cavities immediately before restoration and at each clinical examination using an elastomeric material. The study comprised 274 Class II restorations (88 amalgams, 95 cermets and 91 resin composites) placed in 142 adolescent patients. One hundred and sixty-seven restorations were in molar and 107 in premolar teeth. Patient dropout after 5 years resulted in the loss of 161 restorations, evenly distributed for restorative material and type of tooth involved. Four amalgam restorations, 22 glass ionomer cermet and nine resin composite restorations failed. The glass ionomer cermet and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.     

Randomized clinical comparison of endodontically treated teeth restored with amalgam or with fiber posts and resin composite: five-year results

Prospective clinical studies comparing the results of different types of restorations of endodontically treated teeth are lacking. This study compared the clinical success rate of endodontically treated premolars restored with fiber posts and direct composite to the restorations of premolars using amalgam. Premolars with Class II carious lesions were selected and randomly assigned to one of two experimental groups: (1) restoration with amalgam or (2) restoration with fiber posts and composite. One hundred and nine teeth were included in Group 1 and 110 in Group 2. Patients were recalled after 1, 3 and 5 years. No statistically significant difference was found between the proportion of failed teeth in the two experimental groups. Significant differences were observed between the proportion of root fractures (p=0.029) and caries (p=0.047), with more root fractures and less caries observed in the teeth restored with amalgam at the five-year recall. Within the limits of this study, it can be concluded that restorations with fiber posts and composite were found to be more effective than amalgam in preventing root fractures but less effective in preventing secondary caries.     

Clinical evaluation of reasons for replacement of amalgam vs composite posterior restorations

BackgroundThe aim of the present study is to evaluate the most common reasons for replacing posterior amalgam and resin composite restorations in patients attending the university dental restorative clinics.MethodsA total of 318 restorations which needed to be replaced were clinically and radiographically evaluated in a period of nine months. The frequencies of reasons for replacing posterior amalgam and resin composite restorations were calculated; secondary caries, restoration/tooth fracture, marginal discoloration/ditching, proximal overhang/open margin, loss of anatomy, pain/sensitivity, and esthetics.ResultsThe sample population comprised of 191 females and 106 males. The majority of the sample population fell in the age group of 40–50 years (n = 110). 318 restorations (n = 318) were examined in this study. 82% of examined teeth were restored with amalgam (n = 261), while posterior composite restorations comprised 18% of the examined teeth (n = 57). Among all restorations demanded to be replaced by the patients (n = 318), aesthetic need was the most common reason (n = 98), followed by Ditching or discoloration (n = 64), secondary caries (n = 57), and fracture (n = 44). Loss of anatomy was the least common cause to replace both amalgam and resin composite restorations (n = 5). The different reasons of failure were all significant between amalgam and resin composite restorations as shown in (Fig. 1) (p < 0.005). The most common reason for amalgam replacement was aesthetic. The most common reason for composite replacement was secondary caries and marginal ditching.ConclusionBoth amalgam and composite had different reasons for replacement. Amalgam had lesser risk of developing secondary caries and higher longevity than composite.     

A 3-year clinical evaluation of a gallium restorative alloy

Several alternative materials have been suggested to take the place of amalgam, because of the environmental toxic effects of its mercury component. One such material is gallium-based alloy restoratives. The aim of this in vivo study was to compare the long-term clinical performance of a commercial gallium alloy with an admixed high copper amalgam alloy. For this purpose, 32 gallium and 32 amalgam restorations were placed in molar teeth in 14 human subjects. All the selected patients had at least two molar teeth that required restoration. In this way both restoratives were used in the same oral cavity. The restorations were examined at baseline, 6 months, 1, 2 and 3 years. At baseline, six teeth restored with gallium alloy showed post-operative sensitivity, whereas none of the amalgams were sensitive. At the end of 3 years, only a few amalgam restorations showed slight surface tarnish and marginal integrity loss. None of them needed replacement. Of the 32 gallium restorations placed, five had to be removed because of sensitivity, corrosion and tooth fracture. Also dramatic surface roughness and corrosion were noticed in 12 gallium restoration. According to the results of this clinical study, gallium-based restoratives should not be used before their physical properties are improved.     

Four-year clinical evaluation of posterior resin-based composite restorations placed using the total-etch technique

Purpose : To report the 4-year clinical performance of posterior resin-based composite restorations placed using the total-etch technique.
Materials and Methods : Over a period of 1 year, 726 restorations (248 molars, 478 premolars; 260 Class I, 466 Class II; 540 replacements, 186 primary decay) were placed on conservative preparations, using the incremental placement technique in a clinical environment. Baseline data were collected, and the restorations were evaluated after 4 years. Z100 and Scotchbond Multipurpose (SBMP) (3M Dental Products, St. Paul, Minnesota) were used as the restorative system. The criteria evaluated were color match, marginal adaptation, anatomic form, cavosurface marginal discoloration, axial contour, interproximal contact, secondary caries, postoperative sensitivity, and tooth vitality.
Results : At baseline, 24% of the teeth restored presented postoperative sensitivity; 86% of the sensitive teeth were from the replacement group. At 4 years, all teeth were vital to cold test. Eighteen restorations (2.5%) presented clinically detectable marginal fracture. The shade was acceptable in all restorations. Cavosurface marginal discoloration was observed in 47 restorations (6.5% bravo scores). Axial contour, interproximal contact, and marginal adaptation received 100% alfa scores. No secondary caries was diagnosed in any of the teeth examined. None of the examined restorations required replacement.
CLINICAL SIGNIFICANCE
Under controlled clinical conditions, posterior resin-based composite restorations placed with the total-etch technique and restorative Z1OO/SBMP have the potential to present a high success rate at 4 years. None of the examined restorations required replacement, and there was no clinically detectable wear in any of the restorations. Simultaneous etching of enamel and dentin followed by the application of a resin adhesive can be considered an adequate modality of pulp protection in nonexposed tooth preparations.     

Eight-year study on conventional glass ionomer and amalgam restorations in primary teeth

The aim of this randomized clinical study was to compare the longevity and the cariostatic effects of conventional glass ionomer and amalgam restorations in primary teeth placed in everyday practice in the Danish Public Dental Health Service. All restorations inserted during a 7-month period by 14 clinicians in 2 municipalities were included in the study. The sample consisted of 515 conventional glass ionomer restorations and 543 amalgam restorations in 666 children aged between 2.8 and 13.5 years. The restorations were in contact with 592 unrestored surfaces in primary and permanent teeth. The study was terminated after 8 years, with 2% of the restorations in function and 7% patient dropouts. Fifty percent of the teeth restored with glass ionomer and 63% of those with amalgam were exfoliated with the restoration in situ, while 42% of the glass ionomer and 20% of the amalgam restorations had been repaired or replaced. Fracture of restoration, endodontic complication, and loss of retention were the major reasons for failure. The 50% survival time for glass ionomer restorations in all cavity types was 42 months, while the median survival time for amalgam restorations could not be estimated but exceeded 7.8 years (P < 0.001). Progression of caries lesions on tooth surfaces adjacent to amalgam restorations required operative treatment on 30% of the teeth, while only on 16% of teeth adjacent to glass ionomer restorations. The 75% survival time was 40 months for surfaces in contact with glass ionomer compared to 25 months for surfaces in contact with amalgam (P = 0.005). Multivariate analyses were performed in order to assess the influence of a number of factors on the longevity of restorations, occurrence of prevalent failures, and caries treatment of surfaces in contact with the restorations. Owing to the high frequency of failures of the conventional glass ionomer restorations, it was concluded that they are not an appropriate, universal alternative to amalgam for restorations in primary teeth, although they reduce caries progression and the need for operative treatment of adjacent surfaces.     

Review of bonded amalgam restorations, and assessment in a general practice over five years

This study reviewed the literature on bonded amalgam restorations and assessed the failure, marginal fracture and marginal staining behavior of 366 Permite C amalgam restorations lined with five dentin bonding resins (Scotchbond 2, Panavia Ex, Amalgambond, Amalgambond Plus, Geristore) and a polyamide cavity varnish (Barrier). The restorations were placed in the posterior permanent teeth of 190 adult patients and examined at intervals over periods of up to five years. There were five restoration failures (1.4%), usually from tooth fracture, involving Class II preparations in molar teeth. No instances of persistent pulpal sensitivity or recurrent caries were reported. The marginal deterioration of the restorations was assessed indirectly using photographs for comparison with two standard sets of enlarged color transparencies. Most of the marginal fracture and marginal staining scores were low, with little difference between the six lining materials at any period.     

Reasons for Placement of Restorations on Previously Unrestored Tooth Surfaces by Dentists in The Dental Practice-Based Research Network

ObjectiveThe authors conducted a study to identify and quantify the reasons used by dentists in The Dental Practice-Based Research Network (DPBRN) for placing restorations on unrestored permanent tooth surfaces and the dental materials they used in doing so.MethodsA total of 229 DPBRN practitioner-investigators provided data from their practices regarding 9,890 consecutive restorations in 5,810 patients. Information the practitioner-investigators provided included their reasons for restoring the teeth, the specific teeth and surfaces they restored and the restorative materials they used.ResultsPrimary caries (85 percent of teeth, 8,351 of 9,890) and noncarious defects (15 percent, 1,479 of 9,890) were the main reasons participants gave for placing restorations. Participants placed restorations necessitated by caries most frequently on occlusal surfaces (49 percent, 4,091 of 8,351). They used amalgam for 47 percent of the molar restorations and 45 percent of the premolar restorations. They used directly placed resin-based composite (RBC) for 48 percent of the molar restorations, 50 percent of the premolar restorations and 93 percent of the anterior restorations.ConclusionDPBRN practitioner-investigators cited dental caries on occlusal and proximal surfaces of molar teeth as the main reasons for placing restorations on previously unrestored tooth surfaces. RBC was the material they used most commonly for occlusal and anterior restorations. Amalgam remains the material of choice to restore posterior teeth with proximal caries, although the authors noted significant differences in the use of amalgam and RBC by dentists in various regions of the DPBRN.     

Effect of fluoride in amalgam on secondary caries incidence

Abstract – Caries incidence is falling in many developed countries but is believed to be increasing in developing countries. Insofar as treatment for caries is provided, ordinary amalgam restorations are usually the standard choice. These carry a risk of failing due to secondary caries. The aim of this study was to compare the occurrence of secondary caries adjacent to fluoride-containing amalgam with that adjacent to a conventional amalgam under Held conditions in Bahrain. Children ( n =4l5) aged 6-14 yr who required occlusal restorations in two homologous contralateral permanent molar teeth were identified. Using the split-mouth design, one tooth received a fluoride-containing amalgam filling and the other a conventional amalgam restoration. A random method was used to determine which type of filling was placed on each side. After 4 yr, 357 children were still available for examination; of these 5 had to be eliminated from analysis for various reasons. Of the 704 teeth in the analysis, secondary caries had occurred in 135 (86 conventional amalgam. 49 fluoridated amalgam). By comparison with the conventional amalgam, the effectiveness of the fluoride amalgam was 43% (95% C.I. 24.4%, 57.1%) and the net gain 10.3% (95% C.I. 4.75%, 16.3%). The relative risk was 0.570 (95% C.I. 0.444%, 0.731%). Since fluoride amalgam has identical handling properties to conventional amalgam, performs similarly under clinical conditions and costs about the same, it should be the amalgam of choice for restorations in communities where the incidence of secondary caries is high.     

A prospective 8-year follow-up of posterior resin composite restorations in permanent teeth of children and adolescents in Public Dental Health Service: reasons for replacement

Objectives

The aim of the study was to investigate reasons for replacement and repair of posterior resin composite (RC) restorations placed in permanent teeth of children and adolescents attending Public Dental Health Service in Denmark.

Material and method

All posterior RC placed consecutively by 115 dentists over a period of 4 years were evaluated at baseline and up to 8 years later. The endpoint of each restoration was defined when repair or replacement was performed. The influence of patient, dentist and material factors on reasons for repair or replacement was investigated.

Results

A total of 4,355 restorations were placed. Replacements comprised 406 and repairs 125 restorations. The cumulative survival rate at 8 years was 84 %. Failed restorations were most frequently seen due to secondary caries (57 %), post-operative sensitivity (POS) (10 %) and RC fracture (6 %). POS was observed in 1.5 % of the evaluations and reported more often in girls and from teeth restored with a base material. Older dentists showed lower proportion of replaced restorations due to secondary caries than younger dentists.

Conclusion

Posterior RC restorations in children and adolescents performed in general practice showed a good durability with annual failure rates of 2 %. The main reason for failure was secondary caries followed by post-operative sensitivity and resin composite fracture. A high proportion of replaced/repaired RC restorations were caused by primary caries in a non-filled surface.

Clinical relevance

Secondary caries was the main reason for failure of RC in children and young adults. More teeth with post-operative sensitivity and a shorter longevity of restorations were observed when a base material was used.     

Efficacy of bonded and nonbonded amalgam in the treatment of teeth with incomplete fractures

BACKGROUND: This clinical study compared the efficacy of adhesive-retained vs. pin-retained complex amalgam restorations in the treatment of molars with incomplete fractures. Both relief of chewing pain and cold sensitivity were evaluated at two weeks, three months and one year. METHODS: The authors treated 38 patients with a chief complaint of chewing sensitivity on vital molar teeth (40 teeth in the study). A random-number generator determined the treatment method for each tooth. Twenty teeth received bonded amalgam restorations. Twenty teeth received amalgapins or threaded pins to retain the amalgam. Teeth were evaluated for postoperative chewing sensitivity. A visual analog pain scale was used to evaluate cold response to a skin-refrigerant-soaked cotton pellet at each visit. After 12 months, all 40 teeth were available for evaluation. RESULTS: Chewing pain was completely eliminated in all but one tooth. A Student's t-test found no significant difference (P > .05) in preoperative cold sensitivity between the bonded and nonbonded groups. A paired t-test comparison indicated that the teeth in the bonded group were significantly less sensitive to cold after three months and 12 months than they were at the time of the baseline measurements (P < .0001). A paired t-test indicated no significant difference between preoperative and postoperative cold sensitivity scores for teeth in the nonbonded group (P > .05). CONCLUSIONS: Both adhesively bonded and mechanically retained complex amalgam restorations were successful in resolving chewing sensitivity in cracked molars. For 39 of 40 teeth, chewing sensitivity did not return during the one-year follow-up period. At three months and 12 months, cold sensitivity was reduced in the bonded restorations. At all three time periods, cold sensitivity remained similar to baseline levels for the mechanically retained restorations. CLINICAL IMPLICATIONS: Incomplete tooth fracture in molars can be successfully treated by covering fractured cusps with amalgam restorations. This study excluded teeth with prolonged sensitivity to a cold stimulus or those with periodontal evidence of root fracture. With these exclusions, elimination of chewing sensitivity was predictable. Teeth restored with bonded restorations experienced a decrease in sensitivity to a cold stimulus at three months and at 12 months, but not at two weeks. The cold sensitivity of teeth restored with nonbonded restorations was similar at baseline, two weeks, three months and one year.     

Microleakage evaluation in amalgam restorations used with bases.

Marginal leakage in amalgam restorations often precedes the development of secondary caries. One potential way to improve the marginal seal of such restorations, and thus minimize the risk of caries development, is to apply a glass-ionomer base prior to amalgam placement. This study compared microleakage resistance among amalgam restorations placed with and without light-cured glass-ionomer base materials. Preparations were made in extracted human molar teeth. Four groups were studied, including copal varnish, which was used as a control. All specimens were restored with amalgam. Results indicated significantly greater leakage at the cavity wall/base interface for restorations with a copal varnish cavity liner than for those with a glass-ionomer base. Leakage differences among bases were also found at the amalgam/base interface. Best results were obtained with a dual-cure resin-based system. These samples showed minimal leakage at both the cavity wall/base and the base/amalgam interfaces. These findings suggest that light-cured glass-ionomer bases can be effective in the prevention of microleakage in amalgam restorations.     

Placement and replacement of restorations by selected practitioners

BACKGROUND: There are few Australian data on the reasons for placement and replacement of restorations, and the extent to which these are carried out in general practice. METHODS: A survey was carried out of approximately 100 consecutive restorations placed by each of 28 general dental practitioners. The data were coded and statistically analyzed for various associations. RESULTS: Resin composite was used twice as frequently as amalgam as a restorative material, and nearly four times as often as glass-ionomer cement. Secondary caries was the principal reason for replacing restorations, affecting predominantly amalgam restorations in Class I and Class V cavities. Teeth restored with amalgam fractured nearly twice as often as teeth restored with resin composite. The average ages of amalgam, resin composite and glass-ionomers at replacement were 13.6, 7.1 and 5.7 years respectively. CONCLUSIONS: Amalgam has the longest clinical service life, but is associated with more tooth fracture. Secondary caries is the main reason for replacing restorations. The anti-cariogenic effect of glass-ionomer cement is equivocal.     

Effect of different adhesive protocols vs calcium hydroxide on primary tooth pulp with different remaining dentin thicknesses:24-month results

The aim of this randomized, controlled, single-blind and prospective study was to evaluate the clinical and radiographic success rates of three different bonding protocols vs calcium hydroxide liner for protection of the dentin–pulp complex of primary molars with different remaining dentin thicknesses. Two hundred forty primary molar teeth with moderate to deep occlusal caries were restored in 97 children who met inclusion criteria. After cavity preparation, the teeth were randomly assigned into four groups (n = 60/group) with respect to the material used for protection of the dentin–pulp complex: (1) total-etching with 36% phosphoric acid followed by an acetone-based adhesive (Prime&Bond NT), (2) a self-etch adhesive system (Xeno III), (3) an acetone-based adhesive (Prime&Bond NT) without prior acid conditioning, and (4) control: calcium hydroxide cement (Dycal). Teeth in groups 1–3 were restored with a polyacid-modified resin-based composite (Dyract AP) and those in group 4 with amalgam. The remaining dentin thickness was calculated using image analysis software (ImageJ). The teeth were evaluated clinically and radiographically for 24 months. The distribution of restored teeth with minimal remaining dentin thickness (≤0.5 mm) was 3.3, 8.3, 8.3, and 10% for groups 1, 2, 3, and 4, respectively. Despite the absence of pulpal protection in groups 1–3, none of those teeth exhibited any significant clinical or radiographic symptom during the study period. After 2 years, the clinical and radiographic success rate of restorative treatments was 100%. Protection of the dentin–pulp complex with the tested bonding protocols resulted in similar outcomes in mainly shallow and medium deep cavities as compared to calcium hydroxide  amalgam in more deep cavities, when indirect pulp treatment was performed in class I compomer restorations.     

非创伤性充填技术治疗乳磨牙龋疗效观察

目的探讨非创伤性充填技术(ART)修复乳牙龋的疗效及儿童对ART的接受程度。方法选择患牙本质龋的乳牙580颗,分为3组,ART充填198颗,190颗牙作为对照进行银汞合金充填,192颗采用牙钻备洞,玻璃离子充填。1年及2年后复查。结果84.5%儿童使用ART治疗无不适感,91.2%的学生愿意使用ART方法进行治疗。ART组第1、2年的成功率(88.3%、76.0%)与银汞合金对照组(80.5%、71.3%)、牙钻玻璃离子组(89.9%,79.9%)无显著性差异。ART组及牙钻组2年继发龋发生率(10.55%与9.80%)低于银汞合金对照组(22.56%),差异有显著性。结论ART技术简单,效果较好,对于乳牙龋是一种有效的治疗方法。     

Causes of failure among cuspal-coverage amalgam restorations: a clinical survey

BACKGROUND: Investigations of cuspal-coverage amalgam restorations suggest that tooth fracture is the leading cause of failure, while for Class I and II restorations, the leading cause is caries. In this study, the authors evaluated the causes of failure for a large number of cuspal-coverage restorations. METHODS: The causes of failure for 706 cuspal-coverage amalgam restorations were determined through the use of a questionnaire. Dentists from a variety of dental schools; Army, Navy, Air Force, Public Health and Veterans Affairs dental clinics; and private practice were asked to record pertinent information regarding patients and restoration failures from choices provided on a survey form. RESULTS: The survey documented 706 failed restorations. Mandibular first molars accounted for 36.25 percent of all failures. The majority of failures were caused by fractured teeth (24.3 percent), caries (20 percent) and fractured restorations (17.1 percent). Among all of the failed restorations, 82.15 percent were restorable, 9.35 percent were repairable and 8.50 percent were nonrestorable. Among the fractured teeth, 80 percent were restorable, 14.5 percent were nonrestorable and 5.5 percent were repairable. Among the carious teeth, 84 percent were restorable, 8 percent were nonrestorable and 8 percent were repairable. A chi 2 analysis revealed that tooth fracture was more likely to be associated with nonrestorability than either caries (chi 2 = 5.013, P < .05) or restoration fracture (chi 2 = 6.202, P < .05). CONCLUSIONS: The leading cause of failure among the 706 restorations was tooth fracture, which resulted in significantly greater numbers of nonrestorable teeth than either caries or fractured restorations. CLINICAL IMPLICATIONS: Tooth fracture creates a greater risk of nonrestorability than any other cause of failure. Replacement or coverage of fracture-prone cusps is likely to improve the life expectancy of complex amalgam restorations.     

Restorative treatment pattern and longevity of amalgam restorations in Denmark

A survey has been made of the reasons for placement and replacement of 6052 amalgam restorations in Denmark. In patients more than 16 years of age 48% of all restorations were made because of primary caries, and 52% were replacements of failed restorations. In primary teeth 64% and in permanent teeth of children 83% of the restorations were made because of primary caries. The reasons for replacement of restorations were dependent on dentition, age of the patient, and type of restoration. Secondary caries was the most frequent reason for replacement of failed restorations in permanent teeth, comprising a third of all replacements. Marginal discrepancies and bulk fracture of fillings were the other two major reasons. In primary teeth fracture and loss of fillings were the two major reasons for replacement of amalgam restorations, whereas secondary caries caused less than a quarter of all restorations to be replaced. The age of the restorations replaced ranged from 0 to 38 years, and half of the restorations replaced in permanent teeth of adults were less than 7 years old. A shorter longevity of failed restorations was noted in primary teeth and permanent teeth of children.