The smear layer created by scaling and root planing is physiologically eliminated in a biphasic process

Mechanical instrumentation of the root surface causes the formation of a smear layer, which is a physical barrier that can affect periodontal regeneration. Although different procedures have been proposed to remove the smear layer, there is no information concerning how long the smear layer persists on root surfaces after instrumentation in vivo. This study assessed the presence of the smear layer on root surfaces over a 28-day period after subgingival instrumentation with hand instruments. Fifty human teeth that were referred for extraction because of advanced periodontal disease were scaled and root planed (SRP) by a single experienced operator. Ten teeth were randomly assigned to be extracted 7, 14, 21, and 28 days after SRP. Another 10 teeth were extracted immediately after instrumentation (Day 0, control group). The subgingival area of the instrumented roots was evaluated with scanning electron microscopy. Representative photomicrographs were assessed by a blinded and calibrated examiner according to a scoring system. A rapid and significant (p < 0.05, Z test) initial reduction in the amount of smear layer was observed at 7 days, and a further significant (p < 0.05) decrease was observed 28 days after SRP. Interestingly, even 28 days after SRP, the smear layer was still present on root surfaces. This study showed that the physiological elimination of the smear layer occurred in a biphasic manner: a rapid initial reduction was observed 7 days after instrumentation, which was followed by a slow process leading to a significant decrease 28 days after instrumentation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Estadual Paulista School of Dentistry at Araraquara Department of Diagnosis and SurgeryUniversidade Estadual Paulista School of Dentistry at Araraquara Department of Diagnosis and Surger

Healing of intrabony defects following treatment with an oily calcium hydroxide suspension (Osteoinductal). A controlled clinical study.

Contains fulltext : 50104.pdf (publisher's version ) (Closed access)The purpose of the present clinical study was to evaluate the healing of deep intrabony defects following the application of an oily calcium hydroxide suspension (OCHS). Thirty patients suffering from chronic periodontitis, each of whom displayed one intrabony defect, were randomly treated with access flap surgery (AFS) and the application of OCHS (test) or with AFS alone (control). The following clinical parameters were recorded at baseline and at 6 months after therapy: plaque index, gingival index, bleeding on probing, probing depth (PD), gingival recession, and clinical attachment level (CAL). No differences in any of the investigated parameters were observed at baseline between the two groups. At 6 months after therapy, the test group showed a reduction in mean PD from 7.7+/-1.5 to 2.9+/-0.9 mm (P<0.001) and a change in mean CAL from 9.6+/-2.1 to 5.5+/-2.5 mm (P<0.001). In the control group, the mean PD was reduced from 6.9+/-0.9 to 3.7+/-0.9 mm (P<0.001) and the mean CAL changed from 8.5+/-2.5 to 6.4+/-2.7 mm (P<0.001). OCHS resulted in statistically significant higher PD reductions (P<0.01) and CAL gains (P<0.05) than AFS alone. Within the limits of the present study, it can be concluded that: (1) at 6 months after surgery both therapies resulted in statistically significant PD reductions and CAL gains and (2) treatment with OCHS resulted in statistically significant higher CAL gains than treatment with AFS alone