This is revised and updated edition of this book. We have kept the status of the book as per the course prescribed by dental Council of India. We have gone through the books and corrected the grammatical mistakes and tried to illustrate the texts with figures. We are satisfied with the response of the students towards this book. We are also thankful of students and teachers who purpose this book. We are humans, hence apologise for any deficiency or error still persisting in this edition also. Suggestions are most welcome.