Comparison between undergraduate dental students' self-assessment of pre-clinical crown preparation and assessment by two tutors.

Background:In-vitro work showed that bee honey (BH) and royal jelly (RJ) had "improvement effect" on the mechanical performance of fetal membranes. Propolisis is known for its anti-infection properties. Consequently, we tested the possible prophylactic effect of these products against preterm labor (PL). Methods: Fifty-nine gravidas with history of recurrent PL were quasi-randomly assigned into 2 groups: group I (30 women) received daily ingestion of 20 ml of cotton-trifolium BH, 400 mg propolis and 2 grams of RJ from the 15th gestation week until the onset of labor or completion of 38 weeks' gestation; group II (29 women) served as controls. Primary outcomes assessed were: 1) incidence of PL, and, 2) gestation age at birth. Secondary outcomes were: 1) ultrasonic evidence of cervical changes of threatening PL, and, 2) total leukocyte count and C-reactive protein.Results: Twenty-two pregnancies of group I went to term as compared to 13 of controls (75.9 %, 44.8%; P< 0.01). Average gestation weeks at birth were 36.3 and 31.1 (P<0.01 %). Cervical ultrasonographic signs of PL threat were elicited in 11 and 19 cases of groups I and II respectively (36.7, 65.5%; P<0.01). High leukocyte counts and C-reactive protein were found in 10 and 15 women of cases and controls respectively (33.3, 51.7%; P < 0.05). Conclusion: Bee honey, royal jelly and propolis may be effective for reducing the risk of PL. Further studies are required to elucidate the possible mechanisms and the best application route.