DENTAL CARIES CARACTERISTICS, HANDPIECES, HAND INSTRUMENTS, (USED IN PHANTOM LAB) HYSTOPATHOLOGY. BURS. 3rd year, 1st semester

Transcription

1 DENTAL CARIES CARACTERISTICS, HYSTOPATHOLOGY. HANDPIECES, HAND INSTRUMENTS, BURS. (USED IN PHANTOM LAB) 3rd year, 1st semester

2 DENTAL CARIES

3 CARIES Dental caries is a multifactorial chronic, irreversible (except the first stage), hard tissue destructive disease, starting from the surfaces of teeth, and spreading into the deeper area.

4 CARIES Beginning on the tooth surface, and spread deeper and deeper into the dentin. Untill the organic structure of the enamel hasn t been destroyed the process is reversible. Microorganisms are necessary for developing caries. They fermentate carbohydrates producing organic acids decreasing the ph. Balance of remineralisation and demineralisation is important.

5 DENTAL CARIES IS A MULTIFACTORIAL ORAL DISEASE: Primary modifying factors: tooth microorganisms fermentable carbohydrates time Secondary modifying factors: biological environmental geographical socioeconomic status education

6 PRIMARY MODIFYING FACTORS

7 MICROORGANISMS Streptococcus mutans Lactobacillus acidophilus Lactobacillus casei Actinomyces viscosus

8 PREDILECTION PLACES OF CARIES pits and fissures gingival to the proximal contacts root surfaces gingival third of the facial and lingual surfaces of the clinical crown rough tooth surfaces because of enamel developmental problems insufficient poorly polished plaque retentive margins of restorations

9 CLASSIFICATION OF CARIES Location: Anatomically: - coronal caries: - pit-and-fissure caries - smooth-surface caries - root caries Morphologically: - enamel caries - dentin caries - cement caries

10 TYPES OF CARIES Temporally: - active caries lesion - inactive caries lesion ( arrested caries ) - rampant caries (primary teeth) Is it adjacent to an existing restoration or crown?: - primary caries - secondary caries

11 TYPES OF CARIES ACCORDING TO THE INVASION Caries extension: - incipient caries - superficial caries - medium caries - profunda caries - penetrant caries

12 PITS AND FISSURES CARIES Shape contributes to their high susceptibility to caries -> long narrow orifice Morphologie variation: - end blindly - open near the dentin - penetrate entirely through the enamel Caries expands as it penetrates into the enamel -> entry site much smaller than the actual lesion Caries attack extending inward, paralleling the enamel rods Gross appearance is an inverted V with a narrow entrance and a progressively wider area closer to the dentin enamel junction (DEJ)

13 SMOOTH ENAMEL SURFACES V -shaped in cross section, lesion have a broad area of origin and a conical, or pointed, extension toward the DEJ. (Caries attack extending inward, paralleling the enamel rods.)

14 ROOT SURFACE Surface is rougher than enamel Cementum extremely thin U -shaped in cross section Progress more rapidly In recent years, the prevalence of root caries significantly increased -> because of the increasing number of older persons who retain more teeth

15 The time for progression from incipient caries to clinical caries (cavitation) on smooth surfaces is estimated to be 18 months, + or - 6 months. Occlusal lesions develop in less time than smooth- surface caries. Peak rates for the incidence of new lesions occurs 3 years after eruption of the teeth.

16 CLINICAL CHARACTERISTICS OF ENAMEL CARIES Incipient smooth- surface lesion White spot: earliest evidence of caries It can remineralize -> remineralized lesions clinically intact, but discolored, brown or black spots

17 ZONES OF THE INCIPIENT CARIES (FROM THE PULP TOWARD THE TOOTH SURFACE) 1.) Translucent zone: - structureless appearance - pore volume is 1%, 10 times greater than normal enamel 2.) Dark zone - it doesn t transmit polarized light - pore volume 2-4% - formed by deposition of ions 3.) Body of the lesion - largest portion - pore volume 5-25% - bacteria may be present 4.) Surface zone - relatively unaffected - pore volume less than 5%

18 ZONES OF THE SUPERFICIAL CARIES 1.) Full desintegration of the enamel (cavity) 2.) Desintegrated rods 3.) Attacked interrods

19 CLINICAL CHARACTERISTICS OF DENTINAL CARIES Caries advances more rapidly in dentin than in enamel because dentin provides much less resistance to acid attack. Dentinal tubules provide a freeway for the ingress of acids and egress of mineral. Dentinal caries is V - shaped in cross section with a wide base at the DEJ and the apex directed pulpally. Caries advancement in dentin proceeds through 3 changes: 1. Weak organic acids demineralize dentin 2. The organic materials (collagen) degenerates and dissolves 3. Invasion of bacteria

20 ZONES OF DENTINAL CARIES (FROM THE PULP TOWARD THE DEJ) 1.) Normal dentin 2.) Subtransparent dentin - demineralization of the intertubular dentin - damage to the odontoblastic process 3.) Transparent dentin - softer than normal dentin - farther loss of mineral from the intertubular dentin - collagen cross-linking remains intact 4.) Turbid dentin - zones of bacterial invasion - widening and distortion of the dentinal tubules - collagen denatured 5.) Infected dentin - outermost zone - there is no recognizable structure - great numbers of bacteria

21 DENTAL HANDPIECES

22 HANDPIECES Powered rotary cutting instruments, known as dental hand pieces. Two tehnologies are used today for dental handpieces, and each has unique characteristics and benefits. Air- driven handpiece: turbine Electric motor- driven handpiece: micromotor

23 These systems have both advantages and disadvantages: Air- driven handpieces weight less than electric handpieces. The size of the head of the air- driven handpiece is usually smaller. The electric handpieces are quiter than air- driven handpieces. The electric handpieces offer multiple attachments for the motor that can be used for different cutting applications such as denture adjustments and endodontic instrumentation.

24 ROTARY SPEED RANGES The rotational speed of an instrument is measured in revolutions per minute (rpm). Three speed ranges are generally recognized: - low or slow speeds ( < rpm ) - medium or intermediate speeds ( rpm ) - high or ultrahigh speeds ( > rpm )

25 TURBINE Handpiece only contra-angeled Compressed air driving Wheels are in the head of the contaangeled handpiece Speed: - free running speed: rpm - speed for load: half of the free runing speed Directon of the running can t be changed Speed for load is change Water- air spray is necessary

26 MICROMOTOR (ELECTRIC MICROMOTOR) Handpiece can be contra-angeled and straight Electric driving Speed: rpm Direct of the running can be changed Speed for load is constant Water air spray can be switched on or off (depends on the speed) Revolution can be change with akcelerator or reductor handpieces

27 MICROMOTOR Blue ring 1: rpm Red ring 1: rpm Green ring 5: rpm

28 HANDPIECES The handpiece holds the rotating instrument, and transports the power for rotating instrument. It can be: - straight handpiece - conta-angeled handpiece: friction grip (FG) type burs latch- type burs

29 BURS

30 PARTS OF BURS Shank: fits into the handpiece. Length, crossection and the end-shape can be different. Shank designe: - long shank used for straight handpiece (low speed) - latch-type shank used for contra-angle (low speed) - friction grip shank used for high speed handpiece Neck: transmit the rotational and translational forces to head. It has taper form, and the taper can influence the visibility, the acces and the strength. Head: makes the preparation. The shape and the material of the head depends on the work (enamel, dentin or carious dentin).

31 HEAD OF THE BURS The material of the head can be: - diamond burs - metall burs: -steel -carbide We can identify each type of bur with ISO number, which showes the size, the shape, the roughness and the material of the burs. Diamond: is an abrasive instrument. These are made from diamond chips bonded to blanks/head. Diamonds used for grinding enamel and dentin surfaces.

32 Diamond instruments consists of three parts: - the metal blank - the powdered diamond abrasive - a metallic bonding material that holds the diamond powder onto the blank Diamond particle size and color coding: - super coarse: um Black ring - coarse: / / um Green ring - medium/standard: / um Blue ring or no ring - fine: 60-74/53-63 um Red ring - extra fine: 38-44/20-30 um Yellow ring - ultra fine: - 15um White ring

33 DIAMOND BURS

34 Metal: has bladed cutting edges. - Steel: cut the dentin at low speed well, but not good for enamel preparation. - Tungsten carbide: perform better at all speeds. It is possibility to use both into the enamel and dentin. Carbide burs can also be used to cut through metal. - The more are the number of the blades, the smoother is the prepared surface. - The direction of blades can be straight (or axial) and spiral. Both can be manufactured with or without crosscuts.

35 TUNGSTEN CARBIDE AND STEEL BURS

36 SHAPE OF THE BURS Round Straight fissure Tapered fissure Pear-shaped Inverted cone Flame

37 HAND INSTRUMENTS (USED IN PHANTOM LAB)

38 PROBE OR EXPLORER Probes are possible to detect: detecting caries lesions surface smoothness margins of restorations calculus dentis / tartar orifices of rootcanal

39 DENTAL MIRROR Function of dental mirror: inspection of upper teeth directly not visible areas light reflection distal surfaces retraction of soft tissues

40 TWEEZERS OR FORCEPS Hand instruments with two narrow and pointed, straight or curved beaks to grasp small objects. To hold cotton roll To hold different material To transfer any material in and out of oral cavity

41 RESTORING INSTRUMENTS

42 SPATULA Doubles ended instrument Used for manual mixing of cements supplied as powder and liquid A variety of materials in operative dentistry require mixing, some on a glass slab, others on a paper pad. Several spatulas are available, and they vary in size and thickness.

43 CONDENSING INSTRUMENT To pack material into prepared cavity. Are double-ended instruments with the condensing tips coming in different size and shapes.

44 BURNISHING INSTRUMENT Hand instrument with rounded edges used to polish or burnish the surface of metallic restorations by rubbing. Burnishing is the process of rubbing usually performed to make a surface shiny or lustrous. Double-ended.

45 CARVING INSTRUMENT Hand instrument with a blade or nib used to contour the surface of filling material in their plastic state. Used to remove the excessive material To produce the normal tooth anatomy

46 HEIDEMANN SPATULA To carry and shape tooth colored restorative material: composite resin and glass ionomer.

47 EXCAVATOR Used to cut hard or soft tissues of the tooth, and remove.

48 AMALGAM GUN Insertation of amalgam filling material in to the prepared cavity.

49 THANK YOU FOR YOUR ATTENTION!