Molluscan products are good demand of the international market. Different species of bivalve and gastropod are utilized as food, shells for ornamental purposes and operculum for cosmetic and medicinal use (Ramesh et al., 1990). Excavation of sub-fossil molluscan shell in Pulicat coastal lake is conspicuous and the investigation of shell mining was studied in detailed. Every month, the amount of molluscan shell mining varied from 1650 tons to high 2940 tons and the mean amount of shell excavated was 2383 tons and annual yield of lime shells mining from Pulicat coastal lake is around 28,600 to 30,000 tons. Men and women around 350 to 490 individuals were engaged in excavation. Total shell collection days, and persons engaged in each month varied between 22 to 28 days and per day 70 boats and each boat 5 to 7 person group’s together start to excavate the molluscan shells. From each boat about 1200 to 1500 kg of shells are obtained. Lime shells are used by factories for manufacturing calcium carbide.

Tooth extraction is the most common, basic and widely used therapeutic operation in oral and maxillofacial surgery. Among them, mandibular impacted wisdom tooth extraction is the most common in tooth extraction surgery of oral and maxillofacial surgery, with common postoperative complications such as pain, swelling, bleeding, infection, limitation of mouth opening, nerve injury and so on. In recent years, with the rapid development of minimally invasive medicine and alveolar surgery technology, there is an urgent need for a tooth extraction technique with less trauma, less bleeding, less pain and quick healing, thus minimally invasive tooth extraction arises as the times require. At present, minimally invasive tooth extraction instruments commonly used in clinic are: air-driven handpieces, high-speed turbine, ultrasonic bone knife, minimally invasive tooth extraction knife, implant machine, water laser and so on. This review will systematically describe the four different crown cutting methods of minimally invasive extraction of mandibular impacted wisdom tooth by air-driven hand pieces, so as to provide a theoretical basis for the clinical treatment of mesial impacted mandibular third molars.

The human immunodeficiency virus (HIV) is a lentivirus  that causes HIV infection and acquired immunodeficiency syndrome (AIDS). AIDS is a condition in humans in which progressive failure of immune system allows life-threatening opportunistic infections and cancers to thrive. In the present study carried out on 942 patients with various sexually transmitted diseases 65 patients were found to be seropositive for HIV. Out of these 42 were males (64.61%) while 23 were females (35.38%) which are lower than Burzin et al. (2006) from Ahmedabad reported 77.51% males and 22.49% females found seropositive for HIV. Hence, our study support the males are affected than the opposite sex. Among 65 HIV patients, herpes Progenitalis is the commonest STD with 28 cases (43.07%), followed by Syphilis (18.45%), Mixed VDs (12.3%), Molluscum contagiosum (7.69%), Gonorrhoea (6.15%), Chancroid (4.61%), Condyloma acuminate (3.07%), Granuloma Inguinale (1.53%), Lymphogranuloma venereum (1.53%) and Nongonococcal urethritis (1.53%) indicating that HIV is co-supplemented with STDs and such STD patients are high risk of HIV Seropositivity.