TREND OF POSTERIOR TEETH RESTORATION AT IBADAN, NIGERIA

Abstract

Background

A Dental amalgam is the most used restorative material in the posterior region of the mouth and has proven to be remarkably durable; however there has been a global change in recent years to restore posterior teeth with composite resin

Aim & Objectives

To ascertain the trend of posterior teeth cavity restorations at the University College Hospital (UCH) Ibadan, Nigeria.

Methodology

A-5year retrospective analysis of all the restored posterior cavities at the Dental Conservation Clinic, University College Hospital, Ibadan, Nigeria. Class of cavities, the teeth affected, and the type of restoration made, the outcome and the demographics of the patients were part recorded. The data were analyzed using SPSS Version 20, for frequencies, and means were used for continuous variables while chi square was used to compare the categorical variables (P ≤0.05).

Results

A total of 845 teeth were restored during the study period in 368(43.6 %) males and 477(56.4 %) females with mean age of 40.4 ±15.92 years and male to female ratio of 1:1.3. While the first and second molars were the most (62.6%) restored teeth, Class I cavity was the most restored (42.4%) cavity and the majority (80.4%) of the restorations was done with composite. There was a statistical significant reduction in use of amalgam in restoring posterior teeth over the 5 year period. (p=0.000).

Conclusion

The use of amalgam as choice material for restoration of posterior teeth is gradually being replaced by composite in our environment which emphasizes the need to ensure the quality and durability of the composites used

Introduction

The use of amalgam for posterior teeth restoration dates back to 1830 when silver coins filings were mixed with mercury in restoring defective tooth1,2,3. This innovation was improved by the production of the traditional or conventional amalgam by S.S. White in 19001. The use of amalgam for the restoration of posterior teeth is due to its tolerance to a wide range of clinical placement conditions: moderate tolerance to the presence of moisture during placement, biocompatibility, durability or longevity, availability, and the desirable mechanical properties (good compressive and flexural strength).4,5 The shortcomings of dental amalgam however include large tooth tissue waste during tooth preparation for macro-mechanical retention, poor aesthetics (silver colour) and mercury toxicity5.

Composite resin is a tooth coloured restorative material with good tooth colour and the advent of adhesive systems meant minimal tooth preparation. The use of composite was initially in the anterior region (aesthetic zone) but its use has been extended to involve the posterior teeth with improved science of the composite resin6. However, the placement of composite resin is more technique sensitive, moisture sensitive and limited by its polymerization shrinkage7. Improvement in composite materials and techniques, public demand for more aesthetic, tooth-coloured restorations and the health concern of mercury in amalgam are some of the reasons responsible for increase placement of composite7.

While some studies8,9 favor use of amalgam despite its shortcomings, others 10,11 have recommended that composite resin is better accepted now and is gaining ground as alternative restorative material for amalgam. Some studies 12,13 also have found that while the use of composite resin in the posterior region is increasing, amalgam use in this region of the mouth is going into extinction.

This study was thus set out to look at the trend in restoration of cavities in the posterior teeth treated at the Conservation Clinic of the University College Hospital, Ibadan, Nigeria over a 5-year period and to see the most commonly used material for restoration as well as the most restored cavity in the posterior region of the mouth.

Patients & Methods

This was a retrospective study of all the posterior teeth managed at the Conservation Clinic, University College Hospital, Ibadan, Nigeria between January 2009 and December 2013. The data collected from the case files included patients’ demographics, type of teeth affected, class of cavities, defective restorations, type of restoration or re-restoration and period of restoration. Class of cavity was based on GV Blacks classification.14

The data were analysed according to gender, age, type of cavity and restoration using Statistical package for Social Sciences (SPSS) version 20. The analysis included calculation of mean, frequency and chi-square test was used to test association between categorical variables. P value was set at 5%.

Results

A total of 845 teeth were restored during this study period in 368 (43.6%) males and 477 (56.4 %) females within the age range of 16 and 86 years and mean age of 40.4+ 15.92 years. The first and second molar teeth were the most restored teeth (62.6%) and Class I cavity had the highest restoration (42.4%) as shown in Table 1.

Table 1. Percentage Distribution of Class of Cavity restored According to Tooth .

Class of Cavity	Tooth Type
	Premolars No %	1st and 2nd molars No %	3rd molar No %	Total No %
Class I	33 3.9	262 31.0	63 7.5	358 42.4
Class II	41 4.9	80 9.5	5 0.6	126 14.9
Class V	131 15.5	54 6.4	0 0	185 21.9
Defective Amalgam restoration	4 0.5	25 3.0	2 0.2	31 3.7
Access cavity restorations	34 4.0	108 12.8	3 0.4	145 17.2
Total	243 28.8	529 62.7	73 8.7	845 100

Figure 1 shows analysis of restoration based on type of tooth with majority of the teeth (80.4%) restored with composite. Also composite was used more in restoration of teeth and when the type of cavity was considered, with all class V cavities (100%), restored with composite as shown in Figure 2.

Fig 1 . Distribution of posterior teeth restoration .

Fig 2 . Distribution of restoration according to GV Black classes .

Restoration with amalgam was noticed to have declined from 41.5% in 2009 to 4.3% in 2013 while the use of composite during the period increased from 58.5% to 95.7% as shown in Figure 3. There was a statistically significant reduction in the use of amalgam for restoration of posterior teeth over the 5-year period with the trend of restoration showing a reduction in the use of amalgam and an increase with composite restoration (p=0.000).

Fig 3 .

5 years Trend of Amalgam Vs Composite resin in posterior teeth restoration

Discussion

The present study found that use of composite resin to restore posterior teeth is increasing and more favoured than amalgam restorative material in Nigeria which follows what obtains in other parts of the world.

Though the wide use of amalgam as restorative material of choice in the posterior teeth has been reported to be due to its well documented and well tested material and clinical success, easy manipulation, low cost of treatment13,15 however, the need for minimal invasive dentistry, improvement in adhesive dentistry especially in composite material for use in the posterior teeth has led to reduction in the use of amalgam to restore posterior teeth.

In the present study, the trend of restoration has shown a shift in favour of composite when compared with amalgam. The over 80% of all the restoration done in composite recorded in this study is in agreement with a study done in a Brazilian dental School5 which recorded 85.86% in use of composite n the posterior teeth. This may be due to the increase in teaching of use of composite restoration as direct restorative material in operative classes. However, the teaching has been found to still be controversial, because while some schools limit the use of this material to occlusal cavities of posterior teeth alone, some teachers support the use of the material in large cavities of more than two surfaces16,17. The controversy in the number of surfaces to be restored with composite was linked to the fact that some older teachers still believe and teach the use of amalgam for extensive cavities while the younger ones tend towards use of composite resin5.

Restoration of premolars in the present study was more with composite (91.8%) than with amalgam (8.2%). This is in agreement with the work of Parolo et al5who recorded that 90.2% of the premolars were restored with composite resin but higher than what was reported by another study6 in which 43-60% of the premolars were restored with resin. The premolars due to their anatomic configuration and the masticatory load that they bear make them more liable to fracture. Though the resistance to fracture of these teeth with composite resin is controversial, many studies have found higher resistance to fracture when the tooth is restored with composite due to the adhesion of the material to the tooth18^-21.

Also, restoration of first and second molar teeth (77.7%) and third molar (61.6%) with composite was higher than this similar study5. This may be due to differences in the study period and perhaps better composite acceptability within the present study period. Molars restored with adhesive restorations have been found to have stabilization by the resin giving internal splinting and preventing fracture of the tooth22.

This study recorded a significant increase in the trend of more composite usage as restorative material of choice for the posterior teeth which increased from 58.5% to 95% within the study period. This is similar to another study6 that also recorded a significant rise in composite usage and an indication of better patient acceptance and better awareness with improved teaching5,7. It is also in agreement with other studies12, 23 that have shown increase in the use of direct composite resin as a material of choice for filling the posterior teeth cavities.

Though studies have recorded good results with use of amalgam in the posterior teeth despite its short comings, there is however low-quality evidences that resin composites lead to higher failure rate in this region of the mouth 24,25. The choice for use of composite resin in the posterior teeth which is on the increase may also be due to the possible repair of composite when there is failure/fracture rather than total replacement, reframe conservation of tooth favoured by the adhesive property, preference by patient who are getting better informed and want no colour difference in their tooth and the restoration 26^-28.

The limitation of the study

Being a retrospective study that was based on patients’ record, some vital data could have been missed and also it could not afford us the opportunity of actually checking the integrity of the restorations since the patients were not available for assessment.

Conclusions: The use of amalgam as choice material for restoration of posterior teeth is gradually being replaced by composite in our environment which emphasizes the need to ensure the quality and durability of the composites used.