One-year retrospective clinical evaluation of hybrid composite restorations placed in United Kingdom general practices

OBJECTIVE

The purpose of this study was to assess Pertac II restorations placed in general dental practice.

METHOD AND MATERIALS

A total of 86 restorations (14 Class I, 10 Class II, 17 Class III, 5 Class IV, and 40 Class V) using a hybrid composite material (Pertac II) placed in 56 patients (mean age, 39 years) in 5 dental practices in the United Kingdom were assessed after 1 year by a trained evaluator and the dental practitioner who had placed the restoration. All the restorations were assessed for anatomic form, marginal adaptation, surface roughness, sensitivity or discomfort, gingival condition, and the presence or absence of secondary caries.

RESULTS

Thirty-five (43%) restorations were placed in load-bearing situations, 9% of which were assessed as being in "heavy" occlusion. Five (6%) of the restorations were lost (all Class V restorations), 4 from premolars and 1 from a molar. Four were in wedge-shaped cavities and 1 small restoration was actually dislodged during examination. The remaining 81 (94%) restorations were found to be intact, with no secondary caries detected. A high percentage of optimal scores were recorded for both anatomic form and surface roughness.

CONCLUSION

It is concluded that the evaluation demonstrated satisfactory clinical performance of Pertac II restorations after 1 year of clinical service in the wide variety of clinical situations seen in general dental practice. However, the potential for failure of hybrid composite materials in Class V situations appears high. It may be argued that clinicians who wish to use a resin-based material in a Class V situation should use a compomer or microfilled composite.

The aetiology of the non-carious cervical lesion

Erosion and abrasion have been widely reported as causes of non-carious cervical lesions (NCCL). However, more recently, tooth flexure has been implicated in the formation of these lesions generating renewed interest in the pathogenesis of the non-carious loss of cervical tooth substance. This paper considers the causes of erosion and abrasion, related to modern lifestyles, and reviews the literature concerning tooth flexure as a cause of NCCL. A description of different types of NCCL is given, as an aid to determining the aetiology, yet at the same time accepting that the causation and pathogenesis of NCCL is probably multi-factorial resulting in many different clinical presentations. Consideration is given to the indications for treatment of NCCL and to the selection of materials for restoring such defects.

Effect of restored and unrestored non-carious cervical lesions on the fracture resistance of previously restored maxillary premolar teeth

OBJECTIVES

The effect of non-carious cervical lesions (NCCL) on tooth fracture resistance has not previously been investigated. The aims of this in vitro study were to examine the fracture resistance of a group of extracted maxillary premolar teeth with mesio-occlusal-distal (MOD) restorations of amalgam, and restored or unrestored simulated NCCL.

METHOD

Forty sound maxillary, premolar teeth were divided at random into four groups, each of 10 teeth, which were fixed crown uppermost and long axis vertical in stainless steel moulds. Groups 1,2,3 and 4 were prepared with standardized parallel-sided MOD cavities, then restored with amalgam. Groups 1, 2 and 3 were further prepared with standardized NCCL. The NCCL in Group 1 were restored using a resin-modified polyalkenoate (glass-ionomer) cement, and the NCCL in Group 2 were restored with an adhesive composite resin system. The NCCL in Group 3 were left unrestored. The specimens were loaded compressively at 1 mm min-1 using a universal testing machine.

RESULTS

Mean fracture loads (KN) of 1.08, 1.03, 0.98 and 1.14, respectively, were recorded for Groups 1, 2, 3 and 4. Two-way ANOVA and Scheffe's Multiple Range Test showed no statistically significant difference between the groups.

CONCLUSIONS

It is concluded that the presence of a standardized NCCL in an extracted maxillary premolar tooth does not reduce the fracture resistance of the tooth when loaded compressively at 1 mm min-1. The restoration of NCCL with the materials tested did not result in an increase in the fracture resistance of the previously restored premolar teeth, when loaded compressively at 1 mm min-1.