Dental Morphology: Using the Right Instrument for the Job! Presented by: Sara Beres & Janine Sasse-Englert

Transcription

1 Dental Morphology: Using the Right Instrument for the Job! Presented by: Sara Beres & Janine Sasse-Englert

2 Dental Anatomy Review Historically, emphasis in dental hygiene education was placed on the importance of crown anatomy. Since the 1970 s, detailed knowledge of the root anatomy has been emphasized. Today s literature supports the importance of precise root instrumentation. Root Morphology in Periodontal Therapy

3 Today s Course Objectives. Review of Tooth Features Review of Root Concavities Review of Furcation Morphology Instruments to help YOU debride those areas

4 Permanent Anterior Teeth Properties Permanent anterior teeth include the incisors and canines. Figure 16-1 (Courtesy of Margaret J. Fehrenbach, RDH, MS.) Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4 4

5 Succedaneous All permanent anterior teeth are succedaneous teeth. Each one replaces the primary teeth of the same type. Figure 6-22, A (Adapted with permission from Schour I, Massler M: The development of the human dentition, J Am Dent Assoc 28: , 1941.) 5 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5

6 All anterior teeth are thought to be composed of four developmental lobes Lobes 3 labial lobes (mesiolabial, middle labial, and distolabial) 1 lingual lobe Figure 16-2 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 6 6

7 Developmental Depressions Two vertical labial developmental depressions outline the separations among the labial developmental lobes ML and DL developmental depressions. Figure 16-2 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 7 7

8 An anterior tooth has an incisal surface Considred the incisal ridge Its masticatory surface or chewing surface. Incisal Ridge Figure 16-3 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 8 8

9 Crown outline of the anteriors from the proximal of is triangular. Tooth Form Apex at the incisal ridge and the base of the triangle at the cervix. Figure 16-4 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 9 9

10 The incisors function as instruments for biting and cutting food during mastication because of their triangular proximal form. Tooth Form #8 Mesial view Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

11 The canines, because of their tapered shape and their prominent cusp, function to pierce or tear food during mastication. Tooth Form #11 Lingual view Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

12 Anterior Teeth Height of Contourgreatest elevation (greatest pooch ) Height of Contour For both the crown s labial and lingual surfaces is in the cervical third. Figure 16-4 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

13 Contact areas of anteriors are usually centered labiolingually on their proximal surfaces. Contact Areas Have a smaller area than the contacts of posteriors. Figure Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

14 Cementoenamel Junction On each proximal surface, the CEJ curvature of all anteriors is greater than that of the posteriors. Figure 16-4 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

15 Cingulum The lingual surfaces of all anteriors have a cingulum, which is a raised, rounded area on the cervical third of the lingual surface in varying degrees of prominence or development. Figure 16-5 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

16 Ridges may also be present on the lingual surface. Marginal Ridge The lingual surface on anteriors is bordered mesially and distally on each side by a rounded raised border, the marginal ridge. Figure 16-5 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

17 Some anteriors have a more complex lingual surface with a fossa (plural, fossae), which is a shallow, wide depression. Fossa/Fossae Figure 16-6 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

18 Developmental Pits Some may also have developmental pits, which are located in the deepest part of each fossa. Figure 16-6 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

19 Developmental Groove Other anteriors may have on their lingual surface a developmental groove (or primary groove), a sharp, deep, V-shaped linear depression that marks the junction among the developmental lobes. Figure 16-6 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

20 Supplemental Groove In addition, a supplemental groove (or secondary groove) may also be present on the lingual surface of anteriors, which is a shallower, more irregular linear depression than the developmental groove. Figure 16-6 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

21 Root Anteriors usually have one single root. May also have root concavities or depressions as the root is viewed from the proximal. Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

22 Root in Cross Section Three Basic Shapes Triangular: maxillary incisor Ovoid (egg-shaped): canines Elliptic: mandibular incisors (From Darby ML, Walsh M: Dental hygiene: theory and practice, ed 4, St Louis, 2015, Mosby/Elsevier.) Roots that appear triangular or ovoid in cross-section have narrower lingual surfaces Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

23 Root Maxillary anterior teeth roots has great lingual inclination. Mandibular anterior teeth roots varies in angulation from nearly vertical to great lingual inclination Figure 20-9 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

24 Maxillary Central Root Anatomy KEY CONCEPTS TO REMEMBER: - Single Conical shaped, relatively straight root - Cross section: wider at labial and narrower at lingual, creating a rounded triangular shape - Bulbous crowns may create deep mesial and distal concavities at the CEJ

25 Maxillary Lateral Root Anatomy KEY CONCEPTS TO REMEMBER: - Single, narrow root widest labiolingually and narrowest mesiodistally - Cross section: ovoid shape (lingual marginal groove) may be present on crown and root

26 Instrument Suggestions for Maxillary Incisor Challenges Challenge: periodontal pocket associated with lingual groove on maxillary lateral Try: Straight explorer Mini blade curette Micro blade curette

27 Explorers Need something long and straight for deeper, narrow pockets TU 17 #3, #3A Orban 11/12 has too many bends for a narrow pocket

28 TU 17 at left 3A below

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30 Curettes Need something long, straight, small blade, round toe Gracey 1/2 mini blade Area specific 70 degree angle between face of blade and shank Langer 5/6 mini blade Universal 90 angle between face of blade and shank

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34 File Diamondtec M/D 7 Careful adaptation to the groove

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36 Instrument Suggestions for Maxillary Incisor Challenges Challenge: grooves and fossae collect stain Try: O Hehir Excavator Discoid Cleoid Toe of posterior curet

37 - Scoop : Edge of scoop is sharp and can remove stain and calculus -Excavator: Your office may have several; keep one sterile for that special situation -Cleoid end of discoid/cleoid good for the grooves; Discoid end good for the fossae

38 Specialty Instruments Look for double ended, multi-purpose instruments Nebraska 128 paired with a Langer 5 mini Ideal pointed tip for groove and interproximals Ideal rounded toe for fossae, pockets

39 Mandibular Central Root Anatomy KEY CONCEPTS TO REMEMBER: - Simple root, widest labiolingually, then mesiodistally - Cross section: narrow oval - Shallow depression extends longitudinally along midportion of root.

40 Mandibular Lateral Root Anatomy KEY CONCEPTS TO REMEMBER: - Root slightly thicker and wider than central - With more pronounced longitudinal root depressions - Cross section: slight hourglass

41 Instrument Suggestions for Mandibular Incisor Challenges Similar to maxillary These teeth are even more narrow; deep pockets hard to access with anything except a straight probe, straight explorer, mini curette blade Keep the longitudinal grooves in mind Similar fossa without the groove, less pronounced Tendency for heavy supragingival calculus build-up

42 Straight explorer

43 Keep the toe adapted as you walk around the line angle to get into the mesial and distal longitudinal root depressions

44 Regular size blade unlikely to fit mandibular incisors subgingivally

45 Toe is likely off root and in tissue if you try to use a regular blade

46 Curved blade, rounded back; prevent tissue trauma as you walk around the line angle, allow access to root longitudinal grooves

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50 Instrument Suggestions for Mandibular Incisor Challenges Challenge: Large bridge of calculus Can t use ultrasonic Try Chisel = push Hoe = pull

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53 Push from the facial; bridge of calculus comes off on the lingual

54 Get more bang for your buck Use double-ended instruments with different ends Pair a hoe or chisel with a sickle Pair a universal curette with a small sickle Pair two different size sickles, one for heavy, one for fine

55 Maxillary Canine Root Anatomy KEY CONCEPTS TO REMEMBER: - Largest and strongest single roots for either arch - 17 mm LONG! - Cross section: ovoid shape - Possibility of moderate to deep longitudinal grooves

56 Mandibular Canine Root Anatomy KEY CONCEPTS TO REMEMBER: - 15 mm LONG! - Longitudinal root depressions may extend full length of root - Depressions may be EXTREMELY pronounced to the point of creating a facial and lingual component in the apical third

57 Instrument Suggestions for Maxillary and Mandibular Canines Need a long enough sickle blade to reach halfway across the interproximal surface, and it needs to be small enough (width) to fit right up under the contact. Need a long toe to curve into that longitudinal groove Need a long shank to reach a deeper pocket

58 Gracey 7/8 has a long blade Some sickles much longer blades than others

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60 Permanent Posterior Teeth Properties The permanent posterior teeth include the premolars and molars. Figure 17-1 (Courtesy of Margaret J. Fehrenbach, RDH, MS.) Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

61 Occlusal Surface The crown of each posterior tooth has an occlusal surface as its masticatory surface Includes: Marginal ridges 2 or more cusps Triangluar ridges Transverse ridges Fossa, Pits and Developmental Grooves Figure 17-2 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

62 Height of Contour- Posteriors Buccal surface is in the cervical third Lingual surface is in the middle third When compared with anteriors, most of the posteriors are wider LL than MD, except for the mandibular molars. Figure 17-6 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

63 Contact Area In another comparison with anteriors, the contact area of each of the posteriors is wider, usually located to the buccal of center, and is nearer the same level on each proximal surface. Figure Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

64 Cementoenamel Junction On each proximal surface is a CEJ curvature that is less pronounced on the posteriors than on the anteriors. The CEJ is often quite straight for posteriors. Figure 17-6 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

65 Roots Can have two roots, which means it is bifurcated (Mand. Molars) Or with three roots, which means it is trifurcated (Max. Molars) Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

66 Premolars and molars originate as a single root on the base of the crown. Roots This part on these posterior teeth is considered the root trunk. Figure 17-7 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

67 An area between two or more of these root branches, before they divide from the root trunk, is a furcation. Furcations Figure 17-7 Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

68 Furcations (All data from Nelson S: Wheeler s dental anatomy, physiology, and occlusion, ed 10, Philadelphia, 2015, Saunders/Elsevier.) Copyright 2016, 2011, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved

69 Maxillary First Premolar Root Anatomy KEY CONCEPTS TO REMEMBER: - Typically bifurcated in apical or middle third, forming facial or lingual root- 61% of the time - SINGLE ROOT - Mesial Surface has distinct longitudinal groove which may be relatively shallow to deep enough to bifurcate the root - Mesial surface groove makes this tooth periodontally fragile! - Cross section: kidney shaped

70 Maxillary First Premolar Root Anatomy KEY CONCEPTS TO REMEMBER: - Typically bifurcated in apical or middle third, forming facial or lingual roots - BIFURCATED ROOT - Mesial surface has distinct longitudinal groove extending from the contact area to the bifurcation - Distal surface has a groove, but reduced in depth, creating a convex or flat surface

71 7 mm Root Trunk!

72 Maxillary Second Premolar Root Anatomy KEY CONCEPTS TO REMEMBER: - Single root (generally) - Cross section: ovoid shape - Mesial groove not as pronounced as first molar

73 Instrument Suggestions for Maxillary Premolar Challenges Challenge Calculus in mesial depression on max 1 st premolar Try Curved explorer like 11/12 Long and curved blades to reach depression

74 Access that Mesial Depression

75 Mandibular First/Second Premolar Root Anatomy KEY CONCEPTS TO REMEMBER: - Single root (generally) - Cross section: ovoid shape - Large crowns and narrow roots with possible root depressions

76 Instrument Suggestions for Mandibular Premolar Challenges Challenge Calculus on distals under a bulbous crown, usually from the lingual Try Posterior sickle with a blade long enough to reach at least halfway across interproximal, thin enough to reach right up under the contact. Exaggerated roll to keep tip on the root

77 Maxillary First Molar Root Anatomy - 3 roots: palatal (lingual), mesiobuccal, distobuccal - Palatal root is the largest and the longest - Mesiobuccal root is the widest

78 Maxillary First Molar Root Anatomy 3 furcation entrances: Mesial, Facial, Distal - Facial Furcation - 4mm from CEJ

79 Maxillary First Molar Root Anatomy 3 furcation entrances: Mesial, Facial, Distal - Mesial Furcation - 3mm from CEJ and not centered - Broad, flat mesiobuccal root - Best approached from the lingual since the palatal root is not as broad as the mesiobuccal root - The inner or distal surface of the MB root usually has a longitudinal cavity. - Minimal loss of periodontal attachment, the furcation is invaded

80 Maxillary First Molar Root Anatomy 3 furcation entrances: Mesial, Facial, Distal - Distal Furcation - 5mm from CEJ - Very common to be periodontally involved.

81 Maxillary Second Molar Root Anatomy Similar to maxillary first, except roots are closer together creating tighter furcation entrances

82 Mandibular First Molar Root Anatomy Two roots: Mesial and Distal Two furcation entrances: developmental depression on facial and lingual root trunk from bifurcation to CEJ.

83 Mandibular First Molar Root Anatomy 2 furcation entrances: Buccal and Lingual - Buccal Furcation - 3mm from CEJ to furcation - Deep depression on mesial root

84 Mandibular First Molar Root Anatomy 2 furcation entrances: Buccal and Lingual - Lingual Furcation - 4mm from CEJ to furcation - Slight depression on distal root - Furcation is generally narrow and difficult to instrument

85 Mandibular Second Molar Root Anatomy Similar to mandibular first, except all depressions are shallower.

86 Instrument Suggestions for Molar Challenges Challenge Access furcations Try Nabors probe Round file O Hehir Mini curette toe Furcations are in the middle of the surface with the exception of the maxillary 1 st molar mesial furcation Access easier from lingual

87 Nabors probe

88 Cleaning furcations file O Hehir

89 Round file in furcation

90 O Hehir scoops in furcation

91 Mini curette once inserted, turn to get rounded toe in furcation

92 Instrument Suggestions for Molar Challenges Challenge Keeping appropriate working angulation on posterior interproximal surfaces Try Posterior sickle Gracey 15/16, 17/18 Langer 17/18 McCalls universal Curvature of the shank key 11/12 15/16 13/14 17/18

93 Don t be afraid to... Let go Dr. Gracey designed his instruments in the 1940s when stand up dentistry was practiced, before ergonomics were ever considered, before cumulative stress disorders were ever heard of. Don t be afraid to try new instruments and let go of the old AS LONG AS neither you nor the patient is harmed in the process.

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97 Blade too open (more than 70 ) with the 11/12, more effective blade angulation with 15/16

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99 Langer Curettes UNIVERSAL Blade : GRACEY Shank

100 With a Langer, you have to tip the terminal shank toward the surface you re scaling. When the terminal shank is parallel, the blade is too open. They are very efficient can go from toward surfaces to away surfaces in anterior, or mesial of one tooth right to distal of the next in posterior, without switching instruments.

101 Same Challenge with sickles Shank design

102 Instrument Suggestions for Molar Challenges Challenge Root planing Try Queen of Hearts

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104 More challenges Probing the distal of molars, especially 3rds, especially maxillary Right angle probe

105 Keeping the tip on the tooth can be nearly impossible on maxillary 3 rd molars patient can t open wide enough for the handle to drop far enough

106 McCalls 17/18 Distal root depression of more posterior molars Posterior line angles Horizontal strokes Very short Very controlled

107 REFERENCES Fehrenbach, Margaret J, Tracy Popowics, and Mary Bath-Balogh. Illustrated Dental Embryology, Histology, And Anatomy. Print. Jarrell, Beverly and James Padgett. "Root Anatomy And Instrumentation". Access (1994): Print. McKechnie, Lucinda. "Root Morphology In Periodontal Therapy". Dental Hygienist News 6.1 n. pag. Print. Sharuga, Constance. "Furcation Anatomy". Dimensions of Dental Hygiene (2010): Print.