Surface wear on cervical restorations and adjacent enamel and root cementum caused by simulated long-term maintenance therapy

Complications and treatment errors in nonsurgical periodontal therapy

Nonsurgical periodontal therapy can be subject to iatrogenesis, which includes all the complications directly or indirectly related to a treatment. These complications include both operator-dependent harms and errors and the consequences and adverse effects of the therapeutic procedures. The complications arising following nonsurgical periodontal treatment can be categorized as intraoperative and postoperative and can affect both soft and hard tissues at an intra-oral and extraoral level. Soft-tissues damage or damage to teeth and restorations can occur while performing the procedure. In the majority of cases, the risk of bleeding associated with nonsurgical therapy is reported to be low and easily controlled by means of local hemostatic measures, even in medicated subjects. Cervicofacial subcutaneous emphysema is not a frequent extraoral intraoperative complication, occurring during the use of air polishing. Moreover, side effects such as pain, fever, and dentine hypersensitivity are frequently reported as a consequence of nonsurgical periodontal therapy and can have a major impact on a patient's perception of the treatment provided. The level of intraoperative pain could be influenced by the types of instruments employed, the characteristics of tips, and the individual level of tolerance of the patient. Unexpected damage to teeth or restorations can also occur as a consequence of procedural errors.

Effect of two prophylaxis methods on marginal gap of Cl Vresin-modified glass-ionomer restorations

Background. This study evaluated the effect of two prophylaxis techniques on the marginal gap of CI V resin-modified glass-ionomer restorations.

Methods. Standard Cl V cavities were prepared on the buccal surfaces of 48 sound bovine mandibular incisors in this in vitro study. After restoration of the cavities with GC Fuji II LC resin-modified glass-ionomer, the samples were randomly assigned to 3 groups of 16. In group 1, the prophylactic procedures were carried out with rubber cup and pumice powder and in group 2 with air-powder polishing device (APD). In group 3 (control), the samples did not undergo any prophylactic procedures. Then the marginal gaps were measured. Two-way ANOVA was used to compare marginal gaps at the occlusal and gingival margins between the groups. Post hoc Tukey test was used for two-by-two comparisons. Statistical significance was set at P < 0.05.

Results. There were significant differences in the means of marginal gaps in terms of prophylactic techniques (P < 0.001), with significantly larger marginal gaps in the APD group compared to the pumice and rubber cup group, which in turn exhibited significantly larger marginal gaps compared to the control group (P < 0.0005). In addition, the means of marginal gaps were significant in terms of the margin type (P < 0.001), with significantly larger gaps at gingival margins compared to the occlusal margins (P < 0.0005).

Conclusion. The prophylactic techniques used in this study had a negative effect on the marginal gaps of Cl V resin-modified glass-ionomer restorations.

Effects of conservatively treated diseased cementum with or without EMD on in vitro cementoblast differentiation and in vivo cementum-like tissue formation of human periodontal ligament cells

OBJECTIVES

The present study aimed to evaluate the effects of conservatively treated diseased cementum on in vitro cementoblast differentiation and in vivo cementum-like tissue formation of human periodontal ligament cells (hPDLCs), and observe differential effects of enamel matrix derivative (EMD) on in vivo cementum formation by hPDLCs.

MATERIALS AND METHODS

Forty-eight cementum slices and 48 dentin slices were prepared from periodontitis compromised teeth, and hPDLCs were inoculated on to all root slices. Twenty-four co-cultured root slices of each group were used for mRNA expression of cementum attachment protein and CEMP1. With application of EMD, 24 co-cultured root slices (divided into groups C, D, C+E, D+E) were transplanted subcutaneously into nude mice. All root fragments were reviewed by histological analysis and immunohistochemical staining for bone sialoprotein.

RESULTS

mRNA expressions of cementum attachment protein and cementum protein - 1 from hPDLCs on cementum slices were statistically higher than those of dentin slices. Seven specimens of group C and 10 specimens of group C+E revealed a layer of cementum-like tissue (NFC) on surfaces of pre-existing cementum. NFC was thicker in group C+E than in group C. All NFCs were positively stained for bone sialoprotein, however, there was no NFC formation on dentin slices.

CONCLUSION

Conservatively treated diseased cementum promoted in vitro cementoblast differentiation and in vivo cementum-like tissue formation by hPDLCs, and the in vivo effect was enhanced by the presence of EMD.

Effect of different prophylaxis methods on microleakage of microfilled composite restorations

Background and aims

This study was aimed at evaluating the effect of different prophylaxis methods on microleak-age of microfilled composite restorations.

Materials and methods

In this in vitro study, class V cavities were prepared on buccal surfaces of 84 bovine teeth. The teeth were restored with Tetric N-Bond adhesive and Heliomolar composite resin. Subsequent to a thermocycling procedure and three months of storage in distilled water, the teeth were randomly assigned to four groups (n=21): (1) prophylaxis with a rubber cup and pumice; (2) prophylaxis with a brush and pumice; (3) prophylaxis with air/powder polishing device; and (4) no prophylaxis (the control group). Then the teeth were immersed in 2% basic fuchsin for 24 hours and sectioned for microleakage evaluation under a stereomicroscope. Data were analyzed using Kruskal-Wallis and Wilcoxon Signed Rankstests. Statistical significance was defined at p<0.05.

Results

There were no statistically significant differences in occlusal and gingival microleakage between the groups (p=0.996 and p=0.860, respectively). In all the groups gingival margins exhibited significantly higher microleakage values compared to occlusal margins (p<0.0005).

Conclusion

Prophylaxis methods had no adverse effect on marginal leakage of microfilled composite resin restorations.

The effects of scaling and root planing on the marginal gap and microleakage of indirect composite crowns prepared with different finish lines: an in vitro study

The present in vitro study aimed to assess the effects of root surface mechanical instrumentation on the marginal integrity and adaptation of resin composite crowns. The following null hypotheses were tested: no differences exist between finish line and 1) marginal gap or 2) marginal microleakage before and after manual mechanical periodontal maintenance. A total of 56 intact human mandibular molars were randomly distributed into four groups and subjected to standardized tooth preparations for indirect composite crowns with different marginal finish lines (90° shoulder, beveled 90° shoulder, feather edge, chamfer). One-half of the specimens was used as a control and remained untreated, and the remaining half was subjected to root surface procedures simulating five years of semestral mechanical supportive periodontal treatment. The marginal gap and microleakage were evaluated and statistically analyzed. The specimens used as controls showed lower mean marginal gaps than those subjected to the simulated periodontal treatment, whereas the latter showed lower microleakage than the control crowns. Statistically significant differences were recorded for both the experimental variables. The root surface procedures resulted in altered surfaces of the composite crowns. The marginal gap increased after the treatment, whereas the marginal microleakage was reduced. The 90° shoulder and the chamfer preparation could be considered a viable option to fabricate composite crowns, but the beveled 90° shoulder and the feather edge should not be recommended.

Effect of periodontal therapies on indirect restoration: a scanning electron microscopic analysis

The aim of this study was to evaluate the influence of different periodontal therapies on the integrity of indirect restorations by scanning electron microscopy (SEM). Sixty single-rooted bovine teeth were selected and randomly assigned to 12 groups. Inlay cavities were prepared in the cervical region on the center of the cementoenamel junction, and were restored with laboratory processed resin and luted with a resin cement. Twelve periodontal therapies were used (n= 5): C: control (no treatment); MS: manual scaling with Gracey curettes; US: ultrasonic scaling; PP: prophylaxis with prophylactic paste; PS: prophylaxis with pumice-stone; SBJ: sodium bicarbonate jet; MS/PP; MS/PS; MS/SBJ; US/PP; US/PS; US/SBJ. The specimens were prepared and analyzed by SEM. SEM micrographs at ×100 to ×1000 magnification were obtained from the surface of the laboratory resin and the interface of the indirect restorations. The images were evaluated by 3 skillful, calibrated, blinded observers as to the presence of grooves, microcavities and fracture of margins. The results showed that PS produced groves on restoration surface. MS and US produced groves and marginal fractures on the restorations. SBJ resulted in resin cement degradation. These results suggest that except for PS, all procedures had deleterious effects on the marginal integrity of indirect restorations.

A new ultrasonic device in maintenance therapy: perception of pain and clinical efficacy

BACKGROUND

A recently introduced piezo-driven ultrasonic device (Vector) generates longitudinal oscillations. As a result, the instrument tip moves parallel to the tooth surface. By avoiding vertical oscillations, maintenance treatment with the Vector device should be less painful than treatment with conventional systems. We investigated whether patients perceive treatment with the Vector device as less painful than with a conventional ultrasonic device, and whether the clinical efficacy of the Vector device is comparable with that of the conventional ultrasonic device in maintenance patients.

MATERIAL AND METHODS

Thirty-eight maintenance patients with moderate to advanced periodontal disease took part in this prospective, randomized controlled clinical study. Each patients had to have at least two teeth with probing depths of >4 mm. They were treated either with Dentsply (n=22) at a reduced power setting or with the Vector device (n=16). The observation period was 6 months. Probing pocket depth, attachment level, and bleeding upon probing were assessed at six sites on each treated tooth by a blinded investigator Patient were asked to report perceived pain during instrumentation with a visual analog scale immediately after treatment, in the evening of the treatment day, and in the evenings 1 and 2 days after treatment.

RESULTS

Bleeding on probing, probing depth, and attachment level improved in both instrumentation groups from baseline to month 6; however, there was no difference between the two instrumentation modalities. The patients perceived treatment with neither instrument as unpleasant, and their perception of pain intensity both during instrumentation and on the following days did not differ.

CONCLUSION

In maintenance therapy, clinical efficacy of the vector device is comparable with that of conventional ultrasonic device. It makes no difference whether the ultrasonic device at a reduced power setting or the Vector device is used, since patients perceive both instruments as causing very little pain.