Journal of Conservative Dentistry

: 2019  |  Volume : 22  |  Issue : 3  |  Page : 270--274

The causes of failure and the longevity of direct coronal restorations: A survey among dental surgeons of the town of Abidjan, Côte d'Ivoire

Marie-Chantal Avoaka-Boni1, Stéphane X Djolé1, Wendpoulomdé Aimé Désiré Kaboré2, Yolande N D. Gnagne-Koffi1, Alexandra F E. Koffi1,  
1 Department of Conservative Dentistry and Endodontics, University Felix Houphouët-Boigny, Abidjan, Côte d'Ivoire
2 Research Center of Health Sciences (UFR/SDS), University Ouaga I Professor Joseph KI-ZERBO, Ouagadougou, Burkina Faso, West Africa, Burkina Faso

Correspondence Address:
Prof. Marie-Chantal Avoaka-Boni
University Félix Houphouët-Boigny 22 BP 612 Abidjan 22, Côte d'Ivoire, West Africa
Côte d'Ivoire


Objective: This study aimed to itemize the causes for the failure of direct coronal restorations (DCRs) according to the practitioners of Côte d'Ivoire in order to provide recommendations for good practice. Materials and Methods: A descriptive, self-reporting, prospective survey was carried out among 109 dental surgeons (DSs) in the town of Abidjan based on 587 randomly selected practitioners supplied by the National Board of the Order. Results: The results show that 98.10% of the surveyed DSs had previously encountered cases of failure. Fracturing of the restoration, which is the basis for the hiatus, is the main cause of failure according to 51.40% of the surveyed practitioners, followed by pain “under the restoration” cited by 26.20% of them. Failure occurs within 6 months (30.85% of those surveyed), after 5 years (9.6% of those surveyed) for restorations with composite or glass ionomer cement (GIC), while for DCRs with amalgam, failure occurs within 6 months (28.70%), after 5 years (16%) and beyond 10 years (3.20%). Conclusion: The practitioners often encountered failures of DCRs, with fracture of the restoration as the cause. Dental amalgam appears to have a greater longevity than adhesive restorations. Faced with a failure, they more often opted for a replacement of the DCRs rather than a repair.

How to cite this article:
Avoaka-Boni MC, Djolé SX, Désiré Kaboré WA, D. Gnagne-Koffi YN, E. Koffi AF. The causes of failure and the longevity of direct coronal restorations: A survey among dental surgeons of the town of Abidjan, Côte d'Ivoire.J Conserv Dent 2019;22:270-274

How to cite this URL:
Avoaka-Boni MC, Djolé SX, Désiré Kaboré WA, D. Gnagne-Koffi YN, E. Koffi AF. The causes of failure and the longevity of direct coronal restorations: A survey among dental surgeons of the town of Abidjan, Côte d'Ivoire. J Conserv Dent [serial online] 2019 [cited 2023 Jun 8 ];22:270-274
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Full Text


Failure of a coronal restoration occurs when the restoration does not allow the tooth involved to have the functions for which it was undertaken. The notion of evaluation and of substitution or of repair of restoration of use is pervasive in our daily practice.[1],[2] According to Bernardo et al.,[3] one of the main indicators of failure of direct restorations made of composite, amalgam, or glass-ionomer cement is recurrence of the caries.[4],[5] After a dental restoration, numerous factors can affect its longevity. In particular, factors linked to the operative technique, the condition of the oral cavity, and cooperation by the patient.[6] One refers to a failure when these various factors impact negatively on the outcome of these restorations over time. The causes of failure leading to replacement of the restoration can be identified according to the following two criteria: on the one hand, biological complications (secondary caries, dental fracture, and complication relating to the pulp) and, on the other hand, technical complications (fracture or loss of the restoration and discoloration).[7]

In Côte d'Ivoire, direct coronal restorations (DCRs) represent a substantial portion of the coronal restorations that arise on a daily basis.[8] The majority of these dental restoration procedures, in fact, constitute retreatments following failure of the initial treatment, as is the case in France.[9] This situation, which often encountered in practice, is detrimental to the oral-dental health of the populations in Côte d'Ivoire and it leads to an extra cost that is generally borne by the patients. It is in light of this, in our context, where data are scarce that the present study was undertaken. The aim was to assess the knowledge, the skills, and the practices of dental surgeons (DSs) in regard to failures of DCRs. The specific objectives were to:

Determine the frequency of failures of coronal restorations in the daily practice of DSs in Côte d'IvoireIdentify the causes of failure by specifying the longevity of DCRs according to the practitionersPresent the recommendations for good practice indicated by the practitioners.

 Materials and Methods

Selection of the dental surgeons

This was a cross-sectional, prospective, descriptive study. The studied population comprised DSs chosen independently of their gender. Based on the list provided by the National Board of the Order of DSs of Côte d'Ivoire, 150 DSs were selected by a random draw using a list of 128 private and public practices (there are, on average, 612 DSs in the town of Abidjan). This sample is statistically representative of all of the DSs in the town of Abidjan.

Included in the sample were DSs practicing in the private sector as well as those in the public sector, in ten administrative sectors of the town of Abidjan and its suburbs. These sites were chosen because they have a high concentration of practitioners, representative of all of the DSs practicing in Côte d'Ivoire. DSs in training were not included.

Execution of the survey of direct coronal restoration

A form for collecting the data devised for the purposes of the study allowed collection of the relevant information such as information of a general nature (type of practice and the number of years in practice), the average number of patients treated per day, the longevity of the DCRs, the criteria for failure, the frequency of failures of direct coronal reconstitutions, the likely causes, the implemented evaluations of good practice, and the recommendations according to the practitioners.

This form was allowed for progression to a survey by self-administration of a questionnaire: the survey form was delivered to the dental practices by one of the surveyors and filled out by the DS when the former was no longer present. The survey took place over a period of 3 months from April to June of 2016. The collected information was analyzed using Epi Info version 06.01 software (Epi Info version 06.01 software (Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America)). The results obtained are presented in a tabular format.


Of the 150 DSs who were questioned, 109 completed our questionnaire, thus amounting to a participation rate of 72.67%. The results derived from the percentage of the 109 practitioners who ultimately participated in the survey are presented in the accompanying tables.

Characteristics of the sample

The repartition according to the type of practice allowed us to note that a broad cross-section of experience was represented. The DSs of the private sector accounted for 47.70% versus 52.30% in the public sector. The sex ratio was 2.5. The practitioners were mostly (85.30%) trained in Côte d'Ivoire, whereas 11.90% were trained in France and 2.80% in Senegal. The proportion of the surveyed practitioners who had at least 1–5 patients per day was 46.8%.

Coronal restorations carried out by the practitioners

Direct restorations represented 73.40% of all of the coronal restorations carried out by the practitioners.

The dental surgeons most often use plastic material

For the full set of practitioners, amalgam remains the most used material for restoration of posterior teeth (55%), followed by GIC (23.90%) and composite (21.10%).

Criteria for failure of coronal restorations according to the practitioners

For 71.56% of the surveyed practitioners, failure of a restoration translates into a hiatus at the level of the tooth-obturation space. Many (65.14%) attributed it to the presence of pain “under the restoration.” Recurrence of the caries was a source of failure for 62.40% of those surveyed [Table 1].{Table 1}

Frequency of failures of direct coronal restoration

The proportion of DSs who had already encountered a case of failure was 98.10%, and 72.90% of the surveyed practitioners stated that they had, on average, 1–5 patients per month presenting with a failure of a coronal restoration. A fracture of the restoration was the main cause of failure according to 51.40% of the practitioners, followed by pain “under the restoration” according to 26.20%.

Recommendations proposed with a failure

Faced with a defective restoration, more than half of the practitioners (63.50%) redo the restoration with the same material. The proportion of practitioners who stated that they redid it with amalgam within 6 months was 28.70% and a further 28.70% within 1 year. Sixteen percent of the practitioners redid it after 5 years and 3.20% at the end of 10 years. More than half of the surveyed DSs redid adhesive restorations within 6 months (30.85%) and within 1 year (30.85%). Only 9.6% of the practitioners redid it after 5 years [Table 2]. Nearly all of the surveyed DSs (92.70%) participated in postuniversity training, as this allows them to acquire new knowledge according to 60.40% and to improve their daily practices (40.60%).{Table 2}


Characteristics of the sample

The repartition according to the type of practice allowed us to note that 47.70% were in the private sector and 52.30% in the public sector. Other studies have reported similar results.[10],[11] However, others have shown that private practice was more common.[8],[12],[13] The surveyed practitioners had for the most part (85.30%) been trained in Côte d'Ivoire. The others received their training in France (11.09% of them) and in Senegal (2.8% of them). Since 1990, the training of DSs has taken place entirely in Côte d'Ivoire. Hence, the high level of DSs in the sample was trained in this country. Our sample was representative of all of the experience brackets, and the most active categories were situated between 4 and 10 years and those who had >10 years of experience.

Execution of direct coronal restorations

The results show that approximately half of the DSs, or 46.80%, see between 1 and 5 patients per day and that 38.50% of them see between 6 and 10 patients per day. We hence note that 85.30% have an average professional activity with >10 patients per day. The proportion of practitioners performing direct restorations on a daily basis was 73.40%, hence the remarkable preference of these restorations among the care provided by these DSs of Abidjan. This finding was also noted by Matysiak et al.[14] in 2002. They state that coronal restorations constituted 55% of the conservative care. However, they added that the procedures for use need to be adhered to avoid failure of coronal restorations.

Assessment and monitoring of restorations

The vast majority of those surveyed defined failure of a restoration as the presence of a hiatus at the level of the tooth-obturation space (71.56% of the practitioners), the occurrence of pain under the restoration (65.14% of the practitioners), or also the presence of a secondary caries (62.40%). They acknowledged having treated patients who had defective restorations, with the exception of a small number of them (1.90%). The DSs (on average 72.90%) stated seeing 1–5 patients per month, on average, with a failure of a coronal restoration. This rate is high and close to the results of Bonte et al.[9] Indeed, in the course of a study evaluating coronal restorations in general practice, they noted that 60% of the restorations that were performed led to a failure. These failures can be due to another practitioner or the same practitioner who performed the restoration. There were 86.20% who acknowledged having already performed restorations that ended in a failure.

In terms of the longevity of the restoration, a distinction was made between early failures and those that occur in the longer term. The majority of failures were very early, all of them occurring at most after 1 (one) year, according to 57.40% of the practitioners for restorations with amalgam and according to 61.7% of the practitioners for adhesive restorations.

A fracture of the restoration was the main cause of failure followed by pain irrespective of the material used. These results are not in agreement with those of Opdam et al.[15] Indeed, in a study of the longevity of composite restorations, they claim that affliction of the pulp or a complication of the endodontic treatment can be the basis for failure of a restoration a year after it has been performed. Furthermore, studies have reported that a secondary caries appears to be the main manifestation of the failure of a DCRs followed by a fracture of the restoration.[3],[16],[17] However, the results of the present study are not entirely different from those of Brunthaler et al.[18] who revealed that a fracture of the restoration, followed by secondary caries, is the main cause of failure of restorations in the first 5 years after they had been performed. This has been confirmed by van Dijken and Pallesen,[19] who considered fractures to be the main cause of failure of Class IV restorations with composite.

When faced with a case that has failed, 28.70% of the practitioners stated that they redid adhesive restorations after 3 years, as did 23.40% of them for restorations with amalgam in the same timeframe. However, at the end of 5 years, 16% of the practitioners who were asked stated that they redid DCRs with amalgam versus 9.60% for composite. Furthermore, the results of the present study show that for 3.20% of those surveyed, restorations with amalgam lasted >10 years, while the longevity was at most 5 years for adhesive DCRs (composite and GIC). This could reflect a greater longevity of amalgam compared to composite. This is also what other authors have claimed. Indeed, it has been reported that 99.4% of restorations with dental amalgam and 85.5% of the restorations with composite resin lost for at least 7 years.[3] Likewise, the longevity of restorations with resin has been reported to be shorter than the longevity of restorations with amalgam.[6],[20]

The causes of failure remained the same regardless of the longevity of the restoration except for at the level of the composite, where alteration of the hue is the second cause of failure 3 years after being performed. Opdam et al.[15] claimed that, as of the 2nd year, a fracture is a constant reason for failure as also indicated in the present study. Repair, rather than replacement, is being considered more and more to be a viable alternative for replacement of a defective restoration.[2]

Attitudes of the practitioners when faced with a failure

There are several options available to practitioners faced with a restoration. Replacement of the restoration (fully redoing it with the same or another material) was employed by nearly all of the practitioners. Indeed, 63.50% of them redid it with the same material and 37% with another material. Repair or correction (redoing it partially with the same material) was only performed by 26.20% of the practitioners. These results confirm those of Blum et al.[2] who claim that in 75% of cases, the practitioners chose replacement rather than repair.

However, Da Rosa Rodolpho et al.[21] showed that 54% of the defective restorations were repaired instead of being replaced. Adhesion to the protocol to be used with direct restorations, the motivation, and awareness of the patient to maintain proper oral-dental hygiene as well as an adequate technical platform are the main measures to be implemented according to the practitioners in order to avoid a new failure. The roughness of the surface of the biomaterials has an impact on biofilm adhesion. For direct restoration materials, the finishing is generally done in the mouth and the outcome depends on the restoration material that is used. The polishing and finishing stage is, however, important to reduce bacterial adhesion.[22],[23] It has been shown that bacterial colonization begins at irregularities of the surface such as the edges, cracks, grooves, or areas of abrasion and then extends outward. It has, moreover, been shown that the enzymatic activity of saliva [24] and of the bacteria has an impact on composite resin restorations.[22],[23]

These principles can only be constantly maintained by continuous training. In this regard, nearly all (92.70%) of the DSs stated that they take part in postuniversity training with the aim of acquiring new knowledge and to improve their way of doing things. This is reassuring and provides a degree of hope in terms of good practice. Nevertheless, 7.30% of those surveyed do not participate in such training due to a lack of information. Means for motivation, therefore, need to be implemented. This could be by means of incentive ratings, as indicated by all of the DSs who were surveyed, such training is both necessary and essential.


The DSs of Abidjan often encounter failures of coronal restorations. The presence of a hiatus at the tooth-obturation interface and a coronal fracture are the most common causes. Pain “under the restoration” and the presence of secondary caries are the most frequent manifestations. Dental amalgam appears to have a better longevity compared to adhesive restorations based on composite resin or glass-ionomer cement. When a failure occurs, the practitioners generally opt for replacement of the coronal restoration rather than repair. This allows the restored tooth to continue to perform its various functions.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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