Tham khảo tài liệu 'volume 18 - friction, lubrication, and wear technology part 18', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Unusual habits 2-body Saliva Tooth restoration Foreign body . . . Prophylactic causes of wear Toothbrush and dentifrice 3-body Water Tooth restoration Toothbrush Dentifrice Prophylactic pastes 3-body Water Tooth restoration Polishing cup Pumice Scaling and cleaning instruments 2-body Saliva Tooth restoration Instruments . Cutting finishing polishing Cutting burs diamonds 2-body Water Tooth restoration Bur . Finishing burs 2-body Water Tooth restoration Bur . Polishing pastes 3-body Water Tooth restoration Polishing cup Abrasive slurry Physiologic Wear Physiologic wear or attrition Ref 5 is caused by processes involving sliding contact wear contact wear impact without sliding and noncontact wear from food abrasion alone. Sliding contact wear produces the most prominent effects during masticatory function. An example of severe attrition is shown in Fig. 1. Attrition occurs because of function Ref 6 and occurs only where the opposing teeth come into contact Ref 7 so it can be distinguished from erosion see the discussion of Pathologic Wear given below . Fig. 1 Severe occlusal wear resulting from dental attrition. Source Ref 4 Attrition in primitive man was often severe with pupal exposure owing to the nature of the aboriginal diet of tough meat and sandy fibrous plants as studies on both skeletal and living representatives of aboriginal populations have attested Ref 8 9 10 . Fundamental research on the degree and types of attrition found in the teeth of ancient primitive and modern populations has dealt mainly with the wear planes produced on molars surfaces Ref 11 12 13 and with the effects of attrition on facial height Ref 14 15 16 17 and on the position of the temporomandibular joint Ref 16 18 . It is apparent that not all people wear on their teeth the same way. The patterns produced are frequently characteristic of ethnic variations. Improved tooth care and dietary habits have lessened considerably the occurrence of attrition in modern populations. For additional
