HISTORY AND RATIONALE OF OPERATIVE DENTISTRY

HISTORY AND RATIONALE OF OPERATIVE DENTISTRY

1. History and rationale of operative dentistry Dr. Ajay babu gutti Pg 1 st yr

2. Operative dentistry is the art and science of diagnosis, treatment, and prognosis of defects of teeth that do not require full coverage restorations for correction. S uch treatment should result in the restoration of proper tooth form, function, and esthetics while maintaining the physiologic integrity of the teeth in harmonious relationship with the adjacent hard and soft tissues all of which should enhance the general health and welfare of the patient. OPERATIVE DENTISTRY - Sturdvent

3. Past is a history- a common saying in English- but the question is “ can we forget the past or rather should we forget the past?” WINSTON CHURCHILL’s phrase is a befitting reply. He said, “The longer you look back, the further you can look forward.” It is a fact that one cannot evaluate the problem of present without knowing the past. Same is true with dentistry and precisely Operative Dentistry . INTRODUCTION

4. The history of operative dentistry dates back to the era when Babylonians, Assyrians, and Egyptians (4500–4000 BC) were familiar with gold, and Etruscans and Phoenicians (2700 BC) were practicing gold crowns

5. Since then, there have been numerous advances, developments, and researches which have proceeded continuously. These inventions have transformed the practice of operative dentistry into one which is more efficient and more comfortable for the patients as well as for the operating team

6. 18 TH CENTURY The field of operative dentistry embraced all of chairside dentistry during the 18 th  century. It was during this period when maximum progress in the field of dentistry was observed

7. 19 TH CENTURY By the beginning of 19 th  century, dentistry was no longer in the hands of barbers/artisans but was practiced by professionally minded dentists or surgeons

8. 20 th  century With the beginning of the 20 th  century, there came many refinements and improvements in quality of various materials and processes used in restorative dentistry. Physical and mechanical tests combined with fundamentals of engineering science were applied to structure designs and restorative materials. Shortcomings of materials were recognized and improved by the advent of newer technology. 

9. Analgesia and anesthesia Etiology, diagnosis and treatment regimes Equipment and devices Direct restorative materials Indirect restorative materials Illumination and magnification A number of significant occurrences in the history of operative dentistry can be studied by grouping them into the categories of

10. Anesthesia and Analgesia The first ever recorded use of any anesthetic agent dates back to 500 AD, when Peruvians used Coca leaves for psychotropic properties

11. In 1842 Dr. Crawford used Ether as anesthetic

12. In 1884, Carl Koller discovered the analgesic properties of cocaine.   Shortly after, in that same year of 1884, William S. Halsted introduced conduction anesthesia by using cocaine to block the inferior alveolar nerve. Although cocaine was effective for achieving profound anesthesia, it proved to be highly addicting.

13. In 1904 procaine was synthesized by Einhorn and Uhfelder in Germany. When mixed with a very small proportion of epinephrine, this agent was found to be highly effective and safe as a local anesthetic agent for most patients. Procaine was widely used by physicians and dentists into the 1950s and Novocaine is still the name that patients commonly associate with local anesthetics.

14. By the 1950s, lidocaine became widely accepted by the dental profession. It was found to have extreme safety, surpassing that of Novocaine , and lidocaine became a widely used anesthetic agent. Although many other local anesthetic agents are currently in use and nitrous oxide is often used for its analgesic effect, lidocaine remains the principal anesthetic in routine use

15. 2.Etiology, Diagnosis, and Treatment Regimes Pierre Fauchard was the first who suggested humoral imbalance as the main cause of tooth decay and described its prevention. Before the middle of 19 th  century, there was no scientific basis for the causation of dental caries and infection control.

16. Louis Pasteur in 1865 concluded that microorganism caused putrefaction and could be transferred from one place to other by means of solids, liquids, or airborne particles. During his work, he found that some microorganisms could be destroyed by heat or other methods and also provided the basis for the “germ theory” of infection.  Robert Koch cultured, separated, and classified the microorganism and hence discovered that bacilli caused cholera and tuberculosis

17. In 1890, Miller introduced the chemicobacterial theory of dental caries.  In late 19 th  century, the concepts of microbiology and infection were established in medical and dental fields. The importance and methods of sterilization of dental instruments were promoted by the American Dental Association and recorded saturated steam under pressure, best method for the sterilization of dental instruments

18. The venerable G.V. Black was almost single-handedly responsible for the development of the scientific cavity preparation, his work being published in 1891 Although preceded in his work on dental nomenclature by others, Black was the major author of the modern system of nomenclature, presented in 1893.   

19. Another significant advancement for operative dentistry was the introduction of dental hygienists. This occurred in 1906 by Dr. Alfred Fones , who established his own school of dental hygiene  With the addition of a dental hygienist, the dentist was free to perform more operative procedures and had a valuable auxiliary to aid in the treatment and education of patients.

20. By 1874, it was recognized that fluorine had a preventive effect on dental caries. This recognition was to have far-reaching effects. During the first three decades of the 1900s, Dr. Frederick McKay of Colorado Springs observed that mottling of enamel was confined to specific geographical locations.

21. McKay and Dr. Dean showed that fluoride that was naturally occurring in water caused the mottling. Later, Dean demonstrated that by adjusting the level of fluoride in community water supplies to one part per million, mottling could be reduced or eliminated and yet the caries rate was much reduced. This classic work led to the widespread fluoridation Of community water supplies throughout the United States.

22. 3.Equipment and Devices Evidence showed that ancient cultures used primitive drills, trephines, files, and other devices to prepare adequate cavities in teeth.

23. In early 17 th  century, hand-rotated instruments which had clockwise rotating drill were used to make round ornamental cavities in decayed teeth.   

24. POWERED CUTTING INSTRUMENTS EARLY DRILLS were powered by hand. They were of 2 types : Straight hand drill for direct access preparation. b) Angle hand drill for indirect access preparation.

25. They were modified to ROTATORY HANDPIECES . 25 Belt-driven straight handpiece Gear-driven angle handpiece Gear-driven angle hand piece for cleaning & polishing procedures

26. In 1874 most significant development was the introduction of ELECTRIC MOTOR with 1000 rpm. In 1914 it was incorporated in dental unit. Initial handpiece equipments operating speed was maximum of 5000rpm. Then in 1946 all the old units were converted to high speed of 10,000rpm. 26 w -Foot control with rheostat x- Belt-driven straight handpiece y- Three-piece adjustable extension arm z -Electric motor

27. By 1950 speed of 60,000rpm and above had been attained by newly designed equipment's employing speed-multiplying internal belt drives. In1955 Page- Chayes handpiece was the first belt-driven angle handpiece to operate successfully at speed over 1,00,000rpm. 27 Page-Chayes handpiece

28. In 1955 another major breakthrough was the introduction of contra angled handpieces with internal turbine drives in contra angle head. They are of 2 types: Water driven ( Turbo-Jet portable unit . A small turbine in the head of angle handpiece is driven by water circulated by a pump housed in the mobile base.) 28

29. b) Air-turbine handpiece Borden Airotor handpiece (First clinically successful air-turbine handpiece.) Air-turbine straight handpiece with attached motor at the end of handpiece.

30. Dr. Sanford C. Barnum blessed the field of operative dentistry with his discovery of rubber dam in 1864. It was undoubtedly one of the best methods for providing isolation from saliva and soft tissues during the placement of restorations

31. The first machine made burs known as Revelation Burs were introduced by S.S. White Company in 1891. These machine-made steel burs were later replaced by carbide burs when Acheson discovered a technique for making an industrial abrasive composed of silicon carbide in 1891.

32. Josiah Flagg in 1790 invented first dental chair with adjustable headrest and extended armrest for holding instruments.

33. Morrison introduced his first dental chair in 1867 with a wide range of adjustments. The first pump type hydraulic dental chair called the Wilkinson chair was introduced in 1877.

34. In 1954, Dr. Sanford S. Golden  et al . were geared toward sit down dentistry and developed a reclining chair which would allow dentist to sit while performing various restorative procedures.  Since then, there is continuous improvement in the design of dental chair to provide better comforts to the patients and doctor.

35. Modern diamond bur was purposed by Drendrel in 1932, whereas tungsten carbide dental bur was marketed in 1947. Electric high-speed handpieces have now been developed which have surpassed the merits of air-driven high-speed handpieces. Further advances in the dental equipment such as fiber-optic handpiece, smart prep burs, chemical vapor deposition burs, fissurotomy burs, ultrasonic devices, laser systems, and ozone unit have been added to the literature, and research is still going on.

36. 4.Direct Restorative Materials Direct restorative materials are those that can be placed directly in the prepared tooth cavity during a single appointment. During ancient time, the restorative materials were obtained from bone and ivory and later these included waxes, gums, alum, honey, ground mastic, powdered pearl, lead, tin, gold, amalgam, gutta-percha, silicate cement, resins, glass ionomer cement (GIC), etc

37. August Taveau of Paris combined silver and mercury to form silver paste in 1826 and resulted in beginning of dental amalgam, an outstanding development in the field of operative dentistry The amalgam was later introduced commercially into the United States in 1833 by Crawcour brothers by cutting silver from coins and adding excess mercury Dental profession remained hesitant about the use of Amalgam until Black suggested a balanced amalgam formula (silver 72.5% and tin 27.5%) in 1895. To overcome the drawbacks of low copper amalgam alloy, Dr. William developed high copper amalgam in 1963 which enhanced the long-term marginal integrity

38. Gold foil was first introduced in America by Robert in 1795 and was one of the earliest materials available for restoration of teeth. Arthur discovered cohesive gold foil in 1855.This was the major advance of dentistry. Gutta-percha was discovered in India in 1842. In 1848, Hill advocated the use of gutta-percha along with zinc oxide eugenol as temporary filling material.

39. Zinc oxychloride cement was purposed in 1860 and was used as temporary filling material in spite of its low quality. To overcome this, zinc phosphate was introduced in dentistry in 1879, which exhibited improved properties to be used as a filling material and as cement.  Silicate cement was introduced in the United States in the late 19 th  century and early 20 th  century. Silicate was the first tooth-colored material used in esthetic dentistry. Along with advantage of high fluoride release, the silicate cement had disadvantages of its solubility, pulp irritation potential, and desiccation.

40. To overcome the problems of silicates, direct-filling methyl methacrylate resins were invented in 1947. Although they provided esthetic restorations but did not last long because of their inherent higher coefficient of thermal expansion and polymerization shrinkage which eventually led to marginal leakage, postoperative sensitivity, secondary caries, and interfacial staining. To improve these drawbacks, filler particles were added, but fillers could not bind with the matrix and remained separated.

41. A great discovery by Dr. Michael Buonocore of phosphoric acid to increase mechanical bonding of resin to enamel in 1955 opened new gates in the world of bonding resins and cosmetic dentistry.  The efforts and experiments by R. L. Bowen led to the invention of composites in 1962, which nearly obsolete the use of silicate and acrylic resin from esthetic dentistry. With the introduction of ultraviolet light-curing system, the cosmetic dentistry became more convenient and efficient.

42. Another significant advancement in the development of dentin bonding agent aided retention and stabilization of a tooth-colored restoration without excessive removal of sound tooth structure.  Bonding resin is an unfilled or semi filled resin which matches to the resin in the composite but has a lower viscosity to permit easy flow and penetration. Bonding agents are categorized into “generations” according to their evolution. First and second generations bonding agents were developed as a single-step application, whereas the third generation came with three steps included conditioning, priming, and application of bonding agent. Fourth generation came with concept of “hybridization” proposed by Nakabayashi  et al ., in which diffusion and impregnation of resin into partially decalcified dentin followed by polymerization created a resin-reinforced layer or the “hybrid layer.

43.  Fifth generation dentin bonding agents were based on hybridization and wet bonding technique and advantage of having high bond strength. To improve the bond strength and to make the manipulation easy; sixth and seventh-generation adhesive agents have been tried and still are popular in adhesive restorative dentistry. Composite materials were further improved by modifying the resin matrix and filler, which resulted in the introduction of microfilled , hybrid, microhybrid , flowable , packable, and modified hybrid composites.

44. GIC was developed in 1968 and first described and named by Wilson and Kent in 1971. The GIC has been evolved from silicate and polycarboxylate cement and thus acts as a potential replacement for the silicate cement. Due to its adhesion to enamel and dentin and fluoride release for anticariogenic effect, it gained popularity widely in dental profession.  To improve the abrasive resistance, GIC was modified by addition of silver to develop miracle mix or silver cermet by Simmons in 1983.

45. After that, McLean and Gasser introduced Glass Cermet by sintered glass and metal powders to improve wear resistance and flexural strength in 1985.  Resin-modified glass ionomer cement was developed by addition of a hydroxyethyl methacrylate monomer in the polyacrylic acid and their polymerization is initiated along the methacrylate group after exposure of light. More advancements and modifications in the composite and glass ionomer restorative materials aided more benefits in the field of esthetic dentistry.

46. 5. Indirect restorative materials Indirect materials are those that can be used to fabricate restorations in the dental laboratory and then are placed in or on the teeth Placement of indirect materials generally requires two or more visits to complete the restoration.

47. John greenwood was the first who used plaster of paris as impression material. Inflexibility caused fracture upon removal. Developed by Charles stent in 1857 Improves the drawbacks of gutta percha , pop and provided with stability , plasticity, strengthen and red colouration .

48. Alphons poller introduced reversible hydrocolloid in dentistry in 1925 Sears promoted agar hyrocolloid for taking impressions in fixed partial denture In 1953, polysulfide impression materials were came to the operative and prosthodontic dentistry. Then, the discoveries of polyethers , condensation silicone, and addition silicone offered more stable and less messy materials to dentistry

49. Then, art of casting was introduced in Egypt (2500 BC) where lost wax molding process was first developed for gold casting . Nowadays, CAD/CAM system is being used for making inlays and onlays of high strength and with more accuracy. First, chairside ceramic inlay was made in 1985 using CAD/CAM device which was two-dimensional, but in 2000, Cerec 3 was introduced with three-dimensional graphics .

50.   Illumination and Magnification In ancient days of dentistry, only natural light was the source of illumination. After that, artificial lights used were from candles and kerosene lamps.  First, patient lights were purposed in the early 20 th  century after the invention of electricity. Intraoral illumination was enhanced in surgeries with the help of miner-type headlamps and later by small headlamps. For retraction and visualization, mouth mirrors were introduced in the 1800s, which was further improved to front surface mirrors.

51. Dutch businessmen, Hans and Zacharias invented first microscope (simple and compound) and after that Robert Hook and Leeuwenhoek used microscope for their work.  In the middle of 19 th  century, Carl Zeiss, Ernst Abbe, and Otto Schott developed the surgical operating microscope in practice of medicine.  In earlier days of dentistry, magnifying lenses were tried to examine teeth intraorally for gold margins, fissures, and cracks.

52. The magnification provided was not sufficient, and then plastic loupes were assembled with eyeglass frames. These loupes became heavier as the magnification increased and to prevent occupational stresses Dr. Harvey Apotheker and Dr. Jako brought the concept of extreme magnification in the form of a dental operating microscope in dentistry in 1978. 

53.  In 1999, Dr. Gary Carr purposed the first ergonomically configured operating microscope with Galilean optics for routine dental clinical procedures.  Various addition in microscopic accessories have been occurred from 2000 onward such as beam splitter, camera, liquid crystal display screens, video camera, and high definition cameras. Some practitioners use loupes, loupes in conjunction with headlamps, and endoscopes as an alternative to operating microscope according to their ease of handling and visibility of operating field.

54. RATIONALE OF OPERATIVE DENTISTRY

55. GOALS OF OPERATIVE DENTISTRY There are 4 goals or aims PREVENTION : The most significant result of preventive dentistry has been the communal fluoridation. Research and experience have shown that trace amount of systemic fluoride, tested mostly as an additive to water supply, significantly reduced the incidence of dental caries (40-60%). Other forms can be : General health. : Immunization. : Antimicrobial agents. : Diet control. 55

56. : maintaining oral hygiene : Restoring tooth. : Pits & fissure sealants. : Atraumatic restorative technique. The taxonomy of preventive dentistry is: PRIMARY PREVENTION ( prepathosis ) - Fluoride therapy - Diet control - Plaque control - Sealants - Pulp protection etc.

57. SECONDARY PREVENTION (intervention) It involves services of : - Restorative dentistry - Periodontics - Orthodontics - Other fields - TERTIARY PREVENTION (Replacement) It involves services of : - Fixed prosthodontics - Removable prosthodontics - Maxillofacial prosthetics.

58. 2. INTERCEPTION : It can be achieved by: a) Change in patient home care habits. b) Removal of carious tooth tissue. c) Altering tooth form through restoration or selective recontouring d) Enhancing occlusal stability. A positive contribution to the patients oral health is made through such interceptive treatment.

59. 3. CONSERVATION: Now a days it is an important concept in restorative procedure. It can be achieved by: a) Instrumentation approach for removal of carious tissue. b) Design of cavity preparation to retain as much sound tooth tissue as possible. c) Maintain vitality of pulp and health of supporting tissue. d) Preservation of oral tissues , their function and health prevades the principles of operative dentistry.

60. Although tooth preparation for operative procedures originally adhere to the concept of “extension for prevention”, increase knowledge of prevention methods , advanced clinical techniques & improved restoration material have now provided a more conservative approach. More conservative approaches are available for : a) Many typical restorative procedures. b) Diastema closure. c) Esthetic or functional correction of malformed, discolored & fractured teeth. d) Actual replacement of teeth.

61. When compared to past treatment modalities these newer approaches result in significantly less removal of tooth structure. The primary result of conservative treatment is retention of more intact tooth structure and less trauma to pulp tissue and contiguous soft tissue. Stronger tooth structure Restoration easily retained

62. Offer greater esthetic potential Causing less alteration in intra or inter arch relationship. RESTORATION: Reestablishment and maintenance of health, form, function & esthetics are goals of restorative treatment. These goals pertain to – Teeth. - Surrounding tissues. - Entire masticatory system.

63. Other needs for restoration are: - Carious lesion. - Replacement or repair of restoration. - Fractured teeth. -As a part of fulfilling other restorative need. -Tooth may be restored in the preventive sense.

64. Function and Purpose An understanding and appreciation for infection control. Examination not only the affected tooth but also the oral and systemic health of the patient. Diagnosis of the dental problem and must be correlated with other bodily tissues. A treatment plan that has a potential to return the affected area to a state of health and function.

65. An understanding of material to be used to restore the affected area with a realization of both the material limitations and demands. An understanding of the oral environment into which the restoration will be placed. To understand the biological basis and function of the various tooth components and supporting tissues although the knowledge of correct dental anatomy.

66. CONCLUSION During the beginning of dental science, dentistry was merely an art practiced by barber-surgeons or artisans. With the advent in science and technology, dentistry came into hands of professionally minded dentists/surgeons. Slowly and gradually operative dentistry came out as one of the major branches of dentistry and dentists started oriented toward restoring and preserving of teeth. With the innovations and discoveries of new equipment, techniques, materials, and methods, operative dentistry continues to enriched, refined, and grow toward bright future

67. REFERENCES Sturdavent et al : art & science of operative dentistry : New York , 2002. Marzouk (M.A) : operative dentistry, Modern Theory & Practice : Washington University, 1997. Gilmore : Operative Dentistry, Texas , 4th edition. Vimal K Sikri : Text book of Operative Dentistry : Amritsar, 1st edition. Peter Soben : Essentials of Preventive & Community Dentistry : Mangalore, 2000. 67

68. Thank you…..