Restoration Longevity3.5b

Composite Resin

Amalgam

Amalgam Restorations [1]

A direct restoration material composed of an alloy consisting of mercury, silver, copper or tin.

Kolker et al estimated the average survival of amalgam restorations is 22.5 years

Survival rate of 78% over a 5 year period

Amalgam Restorations [1]

Advantages

• Low technique sensitivity

• High longevity & radiopacity

• High compressive strength

• Excellent wear resistance

• Ability to seal marginal spaces over time

Disadvantages

• Lack of aesthetics

• Increased tooth removal during tooth preparation

• Survival rates of between 55-95% over a 5 year period

Reasons for Amalgam Failure [2]

Technical work of dentist

Patient behaviour

Secondary caries Tooth fracture

Cervical overhangs

Marginal ditching

Not so much the material

Main reasons for failure of AMALGAM

Figure 1: Demonstrates Corrosion of the Amalgam Restoration [2]

Figure 1

Composite Resin Restorations [1, 2]

A direct restoration material composed of a monomer and polymer mix of light curable resins.

Main reasons for failure were secondary caries and fracture of restoration

Bernardo et al concluded the overall risk of failure due to secondary caries was 3.5 times higher in composite than amalgam restorations

Survival rates of between 55-95% over a 5 year period

Composite Resin Restorations [2]

Advantages

• Good aesthetics

• Preservation of tooth tissue during prep

• Low thermal conductivity

Disadvantages

• More technique sensitive than amalgam

• Low durability in posterior teeth

Figure 2: Large posterior composite demonstrates marginal discolouration and wear [3].

Figure 2:

Longevity dependant on: [1, 4, 5]

•Plaque adheres better to resin-based composites than amalgam

Oral Hygiene

•High occlusal function is associated with reduced longevity

•Amalgam has greater wear resistance than composites (useful in heavy occlusion or para-function)

•However in normal occlusal function composites perform well

Occlusal Factors

•Class I and II amalgam restorations have survival time between 25-70 years; not representative of the population, as it was on highly motivated patients (dental students and staff)

Preparation Type

Longevity dependant on: [1, 4, 5]

•Failure rate increases for both materials as cavity size and no. of walls involved increases, however this is more pronounced in RBCs

•14.2% of large amalgam restorations needed to be replaced after 5 years as opposed to 19.8% of composite restorations

Preparation Size

•Tooth must be isolated when using RBCs for effective moisture control as moisture contamination compromises the bond

•This is less critical for amalgam

Field Isolation

Longevity dependant on: [1, 4, 5]

•Amalgam corrosion products fill the space between the tooth and restoration … marginal seal improves with time

•Composite polymerisation shrinkage - compromises the marginal seal and increases the risk of secondary caries

Tooth-Restoration Interface

•Age, gender, reason for restoration

•Oral hygiene, caries risk, parafunctional habits

•Levels of cooperation and compliance

Patient-Related Factors

Video Links - explain the failure of amalgam and composite fillings

Studies

Norway Study [4]

Followed 27 dentists in Norway – looking at all of their class II restorations (4030 in total), for over 4 years. Focus was on adolescents

13 amalgams failed = 7.1% of the amalgams placed (lower than composite failure rate)

407 RBCs (a larger number were placed) = 12.4%

Mean annual fail rate for:Amalgam (1.6%) & resin composite (2.9%)  

Norway Study [4]

For BOTH amalgam and composite, the top

reasons for failure were:

• 1. Secondary caries. Composites were much more susceptible: causing 73.9% of the failures. Results may have been affected by the adolescent focused study – their lifestyle increasing secondary caries risk

• 2. Loss of the restoration

Other failure reasons:

• Amalgams: due to tooth fracture. Unlike amalgam - composites crack before the tooth

• Composites: due to marginal defects and poor approximal contact. Short term reasons: un-contoured restorations and porosities

Public Dental Health Service Study [5]

Observed the longevity of resin composite ONLY

Included 2881 patients with a mean age of 13.7 & 4355 restorations were included by 115

dentists

Cavities were either classI or II

Results showed:84% survival rate at

8 yearsAnnual failure rate of

2%

We can compare this with earlier reported annual failure rates in randomised long-

term longitudinal evaluations between

0.5% and 3%

Restorations by dental students study [6]

Measured longevity of 4009 restorations placed by dental students

Summary: Composite really is technique sensitive In the short term, Class II resin composites are failing at a rate

10 times higher than with dental amalgam Results:

6 amalgams (0.35% of amalgams) were replaced during 1 year 84 class II composites (3.6% of composites) were replaced

during 1 year 21 composites of which were replaced in less than a month of

placement

Restorations by dental students study [6]

Reasons for

Restoration Being

Placed by Type of

Restoration

Reason for Failure

Composite Amalgam

Fracture 24 2

Missing 15 1

Void 15 1

Loose 7

Open Contact 7

Residual Caries 5 2

Failed/Defective 5

Sensitive/Painful 4

Open Margin 2

Total 84 6

Elliot, A. 2008 [7]

472 Portuguese children, aged 8-

12 years, with dental caries in

one or more posterior teeth

Randomised to receive either an:

- Amalgam or- Composite restoration

Followed annually for oral

examination and bitewings

If restorations required replacing

= “failure”

Mean annual failure rate• 0.82% for amalgam• 2.21% for

composites

Comparing Long Term Survivalof Amalgam & Composite Restorations [2]

Bernado et al. Survival Rates

Main reason for failure for both types:

- Secondary caries

Risk was 3.5 times higher in composites vs. amalgam

Amalgam

Composite resin

0 20 40 60 80 100

94.4

85.5

Survival rate (%) over 7 years

Rest

ora

tive

Mate

rial

Comparing Long Term Survivalof Amalgam & Composite Restorations [2]

Opdam et al. Survival Rate

Findings: The number of surfaces restored affects the longevity

Summary of Bernado & Opdam studies:

After 7 years, both materials have a high longevity.

5 yrs

10 yrs

0 10 20 30 40 50 60 70 80 90 100

89.6

79.2

91.7

82.2

Composite Amalgam

Survival rate (%)

Ye

ars

Po

st

Pla

cem

en

t

Patient factors influence on restoration failure [7]

32 GDPs were asked to record the reason for placement / replacement of 3196 restorations from a list of potential reasons

The restoration age, material & class were also recorded

Restorations placed:54% amalgam, 32% composite, 8% compomer, 7% glass ionomer

Reasons for placement / replacement: 29% secondary caries, 28% primary caries, 10% margin fracture, 7% tooth fracture, 6% non-carious defects

Mean age of restorations at failure = 7.1 years

How long do direct restorations last? [8]

Burke, F. and Lucarotti, P. (2008) 

Data from 503,965 restoration placements were obtained from 80,000 adult patients (46% male, 54% female)

Summary: Single surface amalgams have better survival rates than class II restorations

10 Year Survival of Amalgam Restorations

How long do direct restorations last? [8]

Burke, F. and Lucarotti, P. (2008) 

Summary: Older patients have restorations with a shorter interval to re-intervention

10 Year Survival of Restorations by Patient Age

Burke et al. 2001 [9]

Reasons for resin composite replacement:

Resin

Com

posite

020406080

100

Secondary Caries

Fractured Restoration

Lost Restora-tion

Wear

Sensitivity Pulpal PainPerc

en

tag

e

Selection of dental materials &longevity of replaced restorations in Sweden [10]

High caries risk patients shorter longevity for resin based composites vs. low / moderate risk patients due to recurrent caries

Larger restorations show greater failure rates(class II = the most frequently replaced cavity)

Restorations replaced by more experienced dentists are shown to have significantly longer longevity

Longevity of restorations depends on:- Operator experience, patient caries risk, material characteristics

Research suggests:Composites longevity is 6 years & amalgams longevity is 16 years

A 24-month Evaluation of Amalgam and Resin-Based Composite Restorations [11]

226 practitioners; 6,218 direct restorations. • 386 restorations failed (6.2 %) during the following 23.7 months 

Number of tooth surfaces restored helped predict subsequent restoration failure … restorations with 4 or more restored surfaces were more than 4 times more likely to fail

Restorative material and tooth type were not associated significantly with longevity

Older patient age was associated highly with failure (P<0.001). Failure rate for children was 4 percent, compared with 10 percent for people 65 years or older

Conclusion

Correctly performed amalgam

restorations in posterior teeth have

higher longevity than resin

composites

These differences are more

pronounced when:- The cavity is larger

&- There are multiple surfaces involved [1]

Annual failure rates in posterior stress-

bearing restorations are:

0% to 7% for amalgam

restorations0% to 9% for direct

composites [12]

References 1. Soares AC, Cavalheiro A. A review of Amalgam and Composite Longevity of

Posterior Restorations. Rev Port Estomatol Med Dent Cir Maxilofac 2010;51:155-164 2. Is it the end of the road for dental amalgam? A critical review. J Conserv Dent.

2008 Jul-Sep; 11(3): 99–107. 3. Wilson NHF, Burke FJT, Mjo¨r IA. Reasons for placement and replacement of

restorations of direct restorative materials by a selected group of practitioners in the United Kingdom. Quintessence International 1997;28:245–8.

4. Kopperud SE, Tveit AB, Gaarden T, Sandvik L, Espelid I. Longevity of posterior dental restorations and reasons for failure. European Journal of Oral Sciences 2012; 120: 539–548. 

5. Pallesen U, Van Dijken JWV, Halken J, Hallonsten AL, Ho¨igaard R. Longevity of posterior resin composite restorations in permanent teeth in Public Dental Health Service: A prospective 8 years follow up. Journal of dentistry 41 (2013) 297–306

6. Overton JD, Sullivan DJ. Early Failure of Class II Resin Composite Versus Class II Amalgam Restorations Placed by Dental Students. Journal of Dental Education March 1, 2012 vol. 76 no. 3 338-340.

References 7. Elliot, A. (2008) The Risk of Failure is Higher for Composites than for Amalgam

Restoration. Journal of Evidence Based Dental Practice. Volume 8, Issue 2: Pages 83-84.

8. Burke, F. and Lucarotti, P. (2008) How long do direct restorations placed within the general dental services in England and Wales survive? British Dental Journal 206

9. Burke FJT, Wilson NHF, Cheung SW, Mjo¨r IA. Influence of patient factors on age of restorations at failure and reasons for their placement and replacement. Journal of Dentistry 2001;29:317–24.

10. Sunnegardh-Gronberg K, Van Dijken J, Funegard U et al. Selection of dental materials and longevity of replaced restorations in Public Dental Health clinics in northern Sweden. Journal of dentistry 2009; 37 (9), pp. 673--678.

11. McCracken MS, Gordan VV, Litaker MS et al. A 24-month evaluation of amalgam and resin-based composite restorations. JADA 2013; 144, 583-593

12. Hickel R, Manhart J.  Longevity of restorations in posterior teeth and reasons for failure. J Adhes Dent 2001;3(1):45–64.