Concepts in Retro Preparation :Concepts in Retro Preparation Saurabh S. Chandra


Contents :Contents Introduction & Definitions Historical background Anatomy of the Apical Root Indications & Rationale Instrumentation & Techniques Root end Cavity Preparation Root end Filling Materials Conclusion References 2 Concepts in Retro-Preparation


Introduction :Introduction Most periradicular lesions originate in the pulp and can be histologically classified granulomas or cysts These develop in response to irritation caused by intra & extra radicular microorganisms associated with the root canal system Lesions may require surgical removal 1 October 2009 3


Slide 4:An important aspect of periradicular surgery is the removal of the diseased tissue associated with the root apex Periradicular surgery comprises of Curretage Root End resection Root end cavity preparation Retrograde filling 1 October 2009 4


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Definitions :Definitions Periradicular is defined as enclosing or surrounding the root portion of the tooth Periapical is defined as area pertaining to the apex of the tooth root Peri radicular Curettage (Apico-curettage) A surgical procedure to remove the diseased tissue from the alveolar bone in the apical or lateral region surrounding a pulpless tooth 1 October 2009 6


Slide 7:Root End Resection (Apicoectomy, Root end amputation, Apico osteotomy) The ablation of the apical portion of the root and attached soft tissue Root End Preparation & Filling (Retrograde fill, Apical root fill, Apical seal, Retrofill) A method of sealing the apical extent of the root canal system through cavity preparation in the resected root end and placement of a restorative filling material 1 October 2009 7


Historical Background :Historical Background Root end resection is identified with pre- Columbian dentistry in Ecuador by Saville Desirabode in 1843 – attributed as “First”; followed by Magitot in 1860 Document suggests Smith in 1871 as being the first to resect a root tip 1 October 2009 8


Slide 9:Pfaff & Berdmore performed root end resections and placed root end fillings of wax, lead or gold in the middle of the 18th century Many other workers reported root end resections and their work has been documented 1 October 2009 9


Slide 10:Brophy – 1880 Claude Martin – 1881 (Father of Root End Resection) Dunn – 1884 Farrar – 1884 G.V Black – 1886 (Long neglected abscesses) Grayston – 1887 (Cocaine anesthesia) Rhein – 1890 Ottolengui – 1892 Carl Partsch – 1895-1900 (Under Chloroform – “Chloroformnakose” & Cocaine “Cocainanasthesia”) Rudolph Weiser - 1900 1 October 2009 10


Anatomy of apical third of root :1 October 2009 11 Anatomy of apical third of root


Slide 12:Apical constriction Cemento dentinal junction Apical foramen 1 October 2009 12


Apical Constriction (MINOR DIAMETER) :Apical Constriction (MINOR DIAMETER) Apical portion of the root canal with the narrowest diameter Reference point for the apical termination of shaping cleaning & obturation 0.5 – 1.5 mm short of the center of apical foramen Location varies with age due to deposition of secondary dentin or cementum 1 October 2009 13


Slide 14:DUMMER’S CLASSIFICATION OF APICAL CONSTRICTION 1 October 2009 14


APICAL FORAMEN :APICAL FORAMEN It is the circumference or rounded edge, like a funnel or crater that differentiates the termination of cemental canal from the exterior surface of the root Diameter varies from 502-681 µm Not always located in the centre of the root apex, it may exist on mesial,distal,labial or lingual surface of the root 1 October 2009 15


Slide 16:From AC the canal widens as it approaches the AF.   It has a conical dentinal portion and inverted cone cemental portion where: AC is located at the narrowest opening of inverted cone AF is located at the base of inverted cone Green-1955 various shapes of apical foramen are: Semi lunar Asymmetric Hourglass Serrated 1 October 2009 16


Apical Delta :Apical Delta There may be two or three apical foramen split by cementum & dentin thus forming apical delta Significance : Cleaning and shaping-difficult Apical stop – difficult Recapitulation-difficult Act as nidus for micro organisms 1 October 2009 17


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CDJ :CDJ The CDJ is the point in the canal where cementum meets dentin It is the point where pulp tissue ends and periodontal tissues begin The location of the CDJ in the root canal varies considerably It generally is not in the same area as the AC, and estimates place it approximately 1 mm from the AF 1 October 2009 19


Root End Resection :Root End Resection 1 October 2009 20


Indications & Rationale :Indications & Rationale Removal of pathologic processes Resorptive processes Fractured root tips Contaminated root apices with attached pathologic tissue Resorption showing Cementoclastic & Dentinoclastic activity 1 October 2009 21


Slide 22:Removal of Anatomic variations Accessory canals, Apical canal bifurcations, apical deltas, severe curves, apical calcifications Removal of operator errors in during non surgical treatment Ledges, Zips, Blockages, Perforations & Separated Instruments Enhanced removal of soft tissue lesion 1 October 2009 22


Slide 23:Access to Canal system Evaluation of apical seal Creation of an apical seal Reduction of fenestrated root apices Evaluation for aberrant canals and root fractures 1 October 2009 23


Instrumentation & Technique :Instrumentation & Technique Efficient root end resection is performed using high speed handpiece (45° or 90°) angled head Surgeons have recommended various BURS: Cross Cut fissure – CLOG & Grooved surface Round Burs (#6 & #8) – Gouging & No flat root Diamond burs – Forms a fine cut surface 1 October 2009 24


Slide 25:Use of Slow Speed straight handpieces with Cross Cut fissure burs – (Buckley 1914) Nedderman used SCM to evaluate cut root surfaces cut with Fissure burs, Cross Cut fissure burs & Round burs with both slow & high speed handpieces Round burs – resulted in ditching & scooping of root surface Fissure burs – produced the roughest surfaces 1 October 2009 25


Slide 26:High speed fissure burs – produced a smoother root surface coupled with tearing and shredding of the GP Slow Speed Fissure burs – showed the smoothest root surface and least disruption of GP “Clinical parameters favour a smooth, flat surface avoiding any sharp edges or spurs of root structures which may serve as an irritant or stimulate resorptive activity” 1 October 2009 26


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Lasers for Root Resection :Lasers for Root Resection Investigators have studied the application of various lasers for resection of the root Kitumura et al studied the application of Er:YAG Komori et al tested Er:YAG and Ho:YAG lasers Both reported a clean, smooth resected root surface when compared to burs 1 October 2009 29


Slide 30:Ho:YAG laser showed signs of thermal damage and the GP had voids present Moritz et al evaluated CO2 laser and reported that the dentin showed less permeability Maillet et al studied the connective tissue response when root ends were cut by Nd:YAG laser Some authors have advocated the use of lasers for sterilization of the periradicular area 1 October 2009 30


Slide 31:The rationale for use of lasers for peri-radicular surgery are: Improve hemostasis Sterilization of the apex Reduction in dentin permeability Decreased post operative pain Reduced risk of contamination as there is no need of the aerosol containing air turbine 1 October 2009 31


Extent of Root Resection :Extent of Root Resection Been a controversial topic over decades “Focal infection theory” has an impact on the periradicular contamination, necrotic cementum and infection of the root apex “The aim is to save as much of the root as possible, but not at the risk of leaving a septic apex” – Pearson 1 October 2009 32


Slide 33:Two main principles dictate the extent of root end resection: The cause of the disease process must be removed (removal of diseased tissue) Adequate room must be provided for inspection and management of the root end 1 October 2009 33


Slide 34:An apical resection of 3 mm should include most accessory and lateral canals, thus eliminate the residual microorganisms and irritants The amount of root to be resected should be evaluated on a case to case basis Clinician must be able to view resected root end, prepare a root end cavity and place a filling 1 October 2009 34


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Techniques forRoot Resection :Techniques forRoot Resection 1 October 2009 37


Slide 38:Technique of root resection employs a lingual to labial bevel, angled to the coronal aspect of the tooth Primarily designed for surgical access & visibility Historically, suggested angles for root bevels have ranged from 30° to 45° Many worked have suggested that it is wise to be flexible and consider all variables involved in each case 1 October 2009 38


Slide 39:From anterior to posterior, the angle of the bevel will gradually go from a direct coronal-facially placed bevel to one of an accentuated coronal and mesial-buccally placed bevel Additional criteria employed to determine the angle and direction of the bevel include: Root inclination & curvature Number of roots Thickness of bone Position of the root in the bone and the arch 1 October 2009 39


Slide 40:The root end can be resected and beveled in 2 ways Once the root end has been exposed, the bur is positioned at the desired angle; the root is shaved away, beginning from the root apex, cutting coronally Bur is moved mesial to distal, shaving the root smooth and flat, exposing the entire canal system and root outline 1 October 2009 40


Slide 41:This is a safe procedure: Allows continual observation of root end during cutting Surgeon can determine: An appropriate end point based on root thickness Root outline Exposure of canals Access to the resected root face and visibility 1 October 2009 41


Slide 42:Second technique is to pre-determine the amount of the root to be resected The bur is positioned at the ideal angle and the root is resected by cutting from mesial to distal Usually, additional root structure must be shaved from the root until the desired exposure is achieved This technique provides an apical segment (for biopsy) and is the technique of choice when resection is done to gain access behind the tooth (lingual aspect) 1 October 2009 42


Current Concepts of Root Resection :Current Concepts of Root Resection Historically, resection and beveling was carried out in order to improve access to the root canal Current biological evidence and advances in preparation techniques, such as the use of ultrasonic surgical tips with an operating microscope, have meant that the angle of bevel should be reduced 1 October 2009 43


Slide 44:In root-end resections a bevel perpendicular to the long axis of a root exposes a small number of Microtubules However, a root resection with a 45° bevel exposes a significantly greater number of tubules, increasing the chance of leakage into and out of the root canal To prevent this, root-end cavity preparations should extend coronally to the height of the bevel 1 October 2009 44


Slide 45:Beveling exposes dentinal tubules, which can allow the leakage of bacterial byproducts and irritants from the root canal past the root end filling In older patients, there will have been greater intertubular sclerosis and this reduces the patency of dentin The root is therefore resected perpendicular to the root canal to reduce the number of exposed dentinal tubules al tubules 1 October 2009 45


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Slide 47:From a biologic perspective , the most appropriate angle for resection is Perpendicular to the long axis of the tooth The rationale behind perpendicular root end resection is based on several anatomic parameters Perpendicular resection 3 mm from the apex is likely to include all apical ramifications Angle of resection increases the dentinal tubules that communicate with the periradicular region 1 October 2009 47


Slide 48:Extending the root end cavity preparation beyond the coronal extent of the root is simpler if the root end resection is perpendicular to the long axis Finally, with a perpendicular root end resection, the stress forces exerted in the apical region are more evenly distributed; this may reduce the propagation of apical fractures and provide a better environment for apical healing 1 October 2009 48


Peri Radicular Surgery of Posterior Maxilla :Peri Radicular Surgery of Posterior Maxilla Periapical surgery of the posterior maxillary teeth is not as common as that of the anterior teeth due to: Anatomic Considerations Limited field of operation Limited vision High risk of iatrogenic errors (Perforations >50%) Inexperience of operators 1 October 2009 49


Slide 50:1 October 2009 50 Surgical approach to posterior teeth Buccal or Transantral Approach Easier to perform Provides more field for operation Better reapproximation (on sound bone) Less risk of perforations Palatal Approach Limited visibility Palatal flaps are time consuming and inconvenient Difficult to reapproximate after surgery Limited field of operation Pooling of blood Greater palatine NAV


Slide 51:1 October 2009 51 Surgical approach to posterior teeth(Transantral approach) Premolars: For single rooted PM’s – Buccal approach For multi rooted PM’s – Palatal root poses a challenge Buccal root is superficially placed and easily exposed Inter radicular bone is drilled away The root tip is resected a greater length in order to provide sufficient access to the palatal root The palatal root is then resected obliquely


Slide 52:1 October 2009 52 Alveolar bone is removed from in front of and below the root apex. NEVER FROM ABOVE ! The root tip should be ground down, rather than resected in order to avoid displacement into the sinus Apicectomy technique for Buccal roots in proximity to antrum


Slide 53:1 October 2009 53 Apicectomy technique for 2 rooted premolars


Slide 54:1 October 2009 54 Post Operative of Apicoectomy in Upper Premolars


Slide 55:1 October 2009 55 Molars: Periapical Surgery Treated by Transantral or Buccal Route Buccal & Palatal Approach May involve Sinus Lift procedure Buccal approach for buccal roots & Coventional Tt. Of Palatal Root


Slide 56:1 October 2009 56 Bucco Palatal Cross Section of Upper Molar


Slide 57:The surgical resection of the Palatal root needs proper treatment planning Palatal roots are relatively wide and straight, thus amenable to conventional RCT Palatal roots are closest to the sinus membrane A buccal approach for the palatal root is risky because: Palatal root is placed very deep thus instrumentation is difficult Antrum is likely to be perforated 1 October 2009 57


Slide 58:1 October 2009 58 Transantral approach for Molars: Raise full mucoperiosteal flap & remove Buccal bone Resect both buccal roots & open lateral wall of sinus (antero-lateral wall of Max.) using bone bur Stop as soon as bluish periostium of sinus appears Loosen periostium from base Of sinus and palatal root is exposed Resect at desired level and retro fill


Slide 59:1 October 2009 59 Post op X-Ray of of Upper 6, in which obturation is done for palatal canal and resection of buccal root tips Post Op X-Ray - Resection done in all 3 roots.


Slide 60:1 October 2009 60 Preventing Root Tip Loss Drill a hole at the apex with a No. 2 Round bur. Prep can be done mesially and distally. Pass a 3/8 circle needle with 6-0 black braided silk to secure the tip after resection (Ref: Jerome & Hill - JOE Vol.21, 1995)


Root End Surface Preparation :Root End Surface Preparation The goal is to produce a root end with optimal conditions for growth of cementum and regeneration of PDL Two important aspects of this process are: Surface Topography Chemical treatment 1 October 2009 61


Root End Surface Topography :Root End Surface Topography Resected root end must be flat, smooth and have no sharp edges or spurs These may serve as irritants and delay the healing process Pearson et al demonstrated better & quicker post operative healing when the resected end was smooth 1 October 2009 62


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Slide 64:The human PDL fibroblast attachment was better to smooth end resected roots Burs have an impact on the topography and the advocated burs are: Lindeman Bone Bur Multifluted carbide finishing bur Fine diamond finishing bur Gutta percha smearing has to be avoided 1 October 2009 64


Root End Conditioning :Root End Conditioning This removes the smear layer and provides a surface conducive to mechanical adhesion and cellular mechanisms for growth and attachment It exposes the collagenous matrix of dentin and retains biologically active substances & enhance the fibroblast attachment to the root surface Citric Acid EDTA Tetracycline 1 October 2009 65


Slide 66:Citric Acid: Used extensively in Periodontic surgery 50% Citric acid ; pH 1 Applied for 2-3 mins to etch diseased root surface to facilitate the formation, new attachment and cementogenesis Results in demineralized root surfaces and fastens the healing process (Craig & Harrison) Some authors have questioned the use of agents at such a low pH 1 October 2009 66


Slide 67:EDTA: Neutral pH, Used extensively in Endodontics Exposes collagen fibers on dentin surface Does not harm surrounding tissues 15% -24% is optimal for root bio-modification EDTA selectively removes minerals from dentin exposing the collagen 1 October 2009 67


Slide 68:Tetracycline: pH 1.8 Removes smear layer, leaving clean and open tubules Shown a trend for greater connective tissue attachment Studies have suggested the use of EDTA is most beneficial for root conditioning as it causes least harm to the surrounding tissues and alters the dentin as desired 1 October 2009 68


Slide 69:Torabinejad et al have reported that EDTA is most advocated for root conditioning However they advised against the use of EDTA when MTA was used as root end filling material, because it may interfere with the hard tissue producing effect of MTA 1 October 2009 69


RETRO PREPARATION :RETRO PREPARATION 1 October 2009 70


Indications :Indications To create an apical seal (Prevent microleakage) In cases where the orthograde filling is inadequate or compromised Post and cores Poorly obturated canals Calcified canals 1 October 2009 71


Slide 72:SEM studies have shown that the act of root-end resection disturbs the gutta-percha seal The preparation for, and the placement of, a root-end filling is therefore recommended whenever root-end resection has been performed Root-end preparations should accept filling materials that predictably seal off the root canal system from the periradicular tissues 1 October 2009 72


Slide 73:Carr and Bentkover have defined an ideal root-end preparation as a class I preparation at least 3.0 mm into root dentin with walls parallel to and coincident with the anatomic outline of the pulp space They also identified five requirements that a root-end preparation must fulfill: 1. The apical 3 mm of the root canal must be freshly cleaned and shaped 2. The preparation must be parallel to and coincident with the anatomic outline of the pulp space 3. Adequate retention form must be created 4. All isthmus tissue, when present, must be removed 5. Remaining dentin walls must not be weakened 1 October 2009 73


Techniques for Root End Cavity Preparation :Techniques for Root End Cavity Preparation This is a crucial step in the establishment of an apical seal The goal is to make a cavity in the resected root that is dimensionally stable to receive a root end filling material It should also avoid any unnecessary damage to the root structure 1 October 2009 74


Slide 75:Ideal preparation is a Class I cavity prepared along the long axis of the tooth to a depth of at least 3 mm The surgical procedure is successful if the cleaning & shaping of the remaining canal system has been done is a proper and aseptic manner 1 October 2009 75


Armamentarium :Armamentarium Small Round burs - # 1/2, 1 Inverted Cone burs - # 331/2, 34 Surgical fissure burs - # 556/700/700R High speed hand piece Miniature Handpieces for Root End (Kavo) Hand instruments DG 16 Hoe Chisels 1 October 2009 76


Slide 77:Slow speed handpiece Root end pluggers Dovgan MTA Gun Amalgam Carriers Cautrey Units 1 October 2009 77


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Long Axis Preparation :Long Axis Preparation Requires the use of miniature handpiece specially designed Tangerud in 1939 designed an angled handpiece 2.5 mm high and 4 mm wide to facilitate root end cavity preparation Current handpieces require minimal space but often obstruct the vision of the operator 1 October 2009 79


Slide 80:Positioning of the bur and handpiece along the long axis Cross Sectional View of GP and Amalgam 1 October 2009 80


Slide 81:Start with a #1 Round bur parallel to the long axis cutting directly into the root canal or filling Depth of preparation should be 2 – 3 mm Recent studies suggest that 1 mm of depth is better Surface interface is decreased Filling materials can be better condensed Lesser leakage 1 October 2009 81


Slide 82:The width of the preparation must encompass the visible root canal system including the anastomoses The ultimate shape should be an inverted cone with the smallest diameter at the root surface 1 October 2009 82


Vertical Slot Preparation :Vertical Slot Preparation Attributed to Matsura 1962 A 5-7mm vertical cut is made with a parallel cross cut, fissure bur from the labial or buccal surface A round bur larger than the fissure bur is inserted into the area of the canal and dropped coronally to the base of the cut Then the round bur is pulled out to the labial or buccal creating a retentive channel 1 October 2009 83


Slide 84:There are 5 advantages: Good surgical access is obtained to root placed deep in the bone Distinct areas of cavity retention are created All dentinal tubules which may communicate from the root surface to the canal are sealed Minimal amount of root structure is removed Slot preparation in roots with 2 canals joined by an anastomosis encompasses the entire canal system (Sufficient space for filling) 1 October 2009 84


Slide 85:Modifications: Use a small inverted cone (#34 / 35) to create the lingual retentive undercut , tapered fissure burs to prepare the vertical cut , decreasing the depth of the vertical cut from 5-7 to 3-5 mm, and the elimination of either the labial or lingual undercut 1 October 2009 85


Transverse Slot Preparation :Transverse Slot Preparation Advocated by Schuffer; rarely practiced today A sufficient amount of facial bone is removed to create direct access to the root Preparation is made, prior to the root end resection, from the proximal or directly from the buccal into the root to the depth of the lingual wall of the canal It is similar to the vertical slot preparation but rotated 90° 1 October 2009 86


Reverse Canal Instrumentation :Reverse Canal Instrumentation Is advocated when the canal cleaning and shaping has not occurred through the crown Or the canal is not accessible through the crown and surgery is required Indications: Poorly cleaned, shaped & obturated root canals Post & cores Canal Calcifications Separated Instruments in coronal or middle thirds 1 October 2009 87


Slide 88:Technique is suggested with or without root end resection K files or H files are bent at 90° angle and held in a hemostat Patent portion of the canal is cleaned and shaped for obturation with GP points, injected cement or reverse silver points Technique is not recommended to supplant good non surgical cleaning, shaping and canal obturation 1 October 2009 88


Ultrasonics :Ultrasonics The recent introduction of ultrasonic tips permits root end preparations that mimic the shape of the canal These instruments exhibit a variety of tip designs, are small, and permit greater access in difficult locations Have been developed in an attempt to solve the major inadequacies and shortcomings of the traditional bur-type preparation 1 October 2009 89


Slide 90:The use of ultrasonic instrumentation during periradicular surgery was first reported by Richman in 1957 when he used an ultrasonic chisel to remove bone and root apices The concept was further developed by Bertrand and colleagues in 1957 when they reported on the use of modified ultrasonic periodontal scaling tips for root-end preparations in periradicular surgery Recently, specially designed ultrasonic root-end preparation instruments have been developed 1 October 2009 90


Slide 91:Ultrasonic preparations are parallel, can be extended to the recommended 3-mm depth, can include anatomic variations such as the isthmus between two canals in a single root, and are generally cleaner because of the irrigation used with the system Root end preparation using ultrasonic instrumentation has been shown to produce preparations that are cleaner, smaller, deeper, and more parallel; they also accurately follow the root canal space An additional advantage to the use of ultrasonics is the decreased bevel required to perform the preparation 1 October 2009 91


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Slide 93:Ultrasonic root end preparation have several advantages over the handpiece Less osseous tissue must be removed More conservative preparations that follow the long axis of the tooth and remain centered Reduced risk of root end perforations Less smear layer is generated Risk of fractures due to ultrasonic vibrations 1 October 2009 93


Ultrasonic Tip Design :Ultrasonic Tip Design Tips with various designs are used for root end preparation Made of stainless steel Tips are left uncoated or coated with diamond or Zirconium nitride Coating increases the cutting efficiency 1 October 2009 94


Slide 95:1 October 2009 95 Diamond Coated Ultrasonic Tips Ultrasonic KiS tips The KiS microsurgical ultrasonic instruments by Spartan are designed for use in endodontic microsurgery. These Diamond Microsurgical Instruments have increased cutting efficiency due to their diamond coating. The dentine surface is left smooth, yet microsurgically rough which results in better application of filling materials


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Slide 99:1 October 2009 99 A, Eight-power dental operating microscope view of root-end preparation using Carr ultrasonic tips. Preparation is 0.5 mm in diameter B, Higher magnification shows smoothness of walls


Microsurgery :Microsurgery 1 October 2009 100


Slide 101:Has been used in the medical field for over 50 years First introduced to Otolaryngology around 1950, then to Neurosurgery in the 1960s, and to Endodontics in the early 1990s It has become an integral part in surgical endodontics since it allows the operator to view the minute structures and work in a precise manner 1 October 2009 101


Slide 102:Pioneers in the use of the operating microscope in surgical endodontics have been Buchanan, Carr, Rubinstein, Pecora and Adreana Surgical telescopes usually magnify in the range of ×2.5 to ×6.0, whereas the surgical operating microscope has a range of magnification of up to ×40 The most significant of these advantages is the enhanced ability to visualize the surgical field and to evaluate the surgical technique 1 October 2009 102


Slide 103:Incomplete root-end resection and failure to identify and properly include an interconnecting isthmus between multiple canals in a single root during root end preparation have been stated as among the major causes of failure in endodontic surgery The use of good illumination and magnification will aid the surgeon in reducing these factors and should result in an increased success rate for endodontic surgery 1 October 2009 103


Slide 104:Rubinstein has identified several advantages of the surgical operating microscope. They include: 1. Visualizing the surgical field. 2. Evaluating the surgical technique. 3. Reducing the number of radiographs needed. 4. Expanding patient education through video use 5. Providing reports to referring dentists and insurance companies 6. Creating documentation for legal purposes 1 October 2009 104


Slide 105:Factors to be considered: Operator experience Indirect view and patient head position Mouth mirror placement Key instruments Cost versus patient benefit 1 October 2009 105


Patient Position :Patient Position To maximize the access and quality of the view by this indirect means, the position of the patient (especially the head position) is important The optimum angle between the microscope and the mirror is 45°, and the clinician should be able to obtain this angle without requiring the patient to assume an uncomfortable position 1 October 2009 106


Slide 107:The maxillary arch is rather easy for indirect viewing The patient’s head is adjusted to create a 90° angle between the maxillary arch and the binocular . In this position, the mirror placement will be close to 45° for best viewing 1 October 2009 107


Key Instruments :Key Instruments Micro mirrors of various angulations Micro scalpels Micro Scissors Set of various elevators Needle holders Curretes Impact Air handpiece 1 October 2009 108


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Slide 110:Developed by Gary Carr Curettes are used to make a sharp dissection of the periosteal tissue, thus preventing tissue damage.They allow for undermining elevation of the flap, which along with the micro-surgical incision 1 October 2009 110


Slide 111:The Impact Air handpiece is an essential tool in endodontic surgery Its head is designed for microsurgery surgery and does not exhaust air, reducing the risk of an air embolism Is ideal for bony access & Root resectioning Its 45° angled head allows maximum visibility and is ideal for accessing tight spaces during endodontic surgery 1 October 2009 111


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Isolation & Hemorrhage Control :Isolation & Hemorrhage Control Localized hemostasis during periradicular surgery is essential to successful management of the resected root end Minimizes surgical time Decreases post operative hemorrhage & swelling Improve s visibility 1 October 2009 113


Local Hemostatic Agents :Local Hemostatic Agents Epinephrine Collagen based materials Surgicel Gelofoam Avitene Bone Wax Ferric Sulfate Calcium Sulfate Cautery/Electrosurgery 1 October 2009 114


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Slide 116:Epinephrine: Sympathommimetic amine Vasoconstrictor 1:1000 to 1:10,000 Cummings et al – 2:100, 2% Racemic Epinephrine Barnes et al – 1:80,000 in a wide ribbon gauze Racemic Epinephrine Pellets – (0.55 mg) Binds to the alpha adrenergic receptors to produce a vasoconstrictive effect 1 October 2009 116


Collagen Products :Collagen Products Consist of collagen of differentiating microstructures and densities They have 4 principal mechanism of action: Stimulate Platelet adhesion, aggregation & release Activation of factor VIII (Hageman Factor) Mechanical action Release of Serotonin 1 October 2009 117


Slide 118:Avitene (Microfibrillar collagen hemostat) is an absorbable topical hemostatic agent prepared from bovine collagen It is flaky to granular in nature and is packed into the osseous cavity It acts like natural collagen by attracting platelets which adhere to the fibrils and forms a physiologic platelet plug 1 October 2009 118


GelFoam :GelFoam Gelatin based sponge, water insoluble & resorbable Made of purified animal skin and becomes soft on contact with blood When the come in contact with blood, they swell up and form a gelatinous mass Action is intrinsic, promoting disintegration of platelets, causing a subsequent release of thromboplastin This stimulates the formation of Thrombin 1 October 2009 119


Surgicel :Surgicel Chemically stabilized substance resembling surgical gauze Prepared by oxidation of regenerated cellulose (α-Cellulose/Oxycellulose) Action is physical and has no effect on the clotting cascade There is a formation of a gel with blood that results in a swollen, sticky mass acting as a mechanical block or artificial coagulum or plug 1 October 2009 120


Slide 121:Surgicel Avitene 1 October 2009 121


Slide 122:Gelfoam 1 October 2009 122


Slide 123:Bone Wax: Introduced by Horsley 1892 Formulation was Beeswax, Almond Oil & Salicylic acid Presently- Beeswax and Isopropyl Palmitate (Ethicon) Hemostatic action is physical by forming a plug and is used to control bleeding from cancellous bone 1 October 2009 123


Cautery / Electrocautery :Cautery / Electrocautery 1 October 2009 124 Stops blood flow through coagulation of blood and tissue protein The effect of the cautery on the bony crypt and periradicular tissues has not been studied to date However, evidence suggests that its use delays the healing process


Ferric Sulfate :Ferric Sulfate Necrotizing agent with a low pH Results in hemostatic control for approx 5 mins and near normal healing with only a mild foreign body reaction Studies have shown failure to remove it from the surgical wound site that resulted in impaired healing Monsel’s Solution (Ferric Subsulfate) is used in dermatological procedures 1 October 2009 125


Calcium Sulfate :Calcium Sulfate Used as a substitute bone graft material since 1800’s Its presence does not inhibit bone formation Its use during surgery does not affect healing and deposition of cementum and osseous healing is as normal It acts a physical barrier and prevents bleeding Can be left in the bony crypt in situ 1 October 2009 126


Root End Filling Materials :Root End Filling Materials 1 October 2009 127


Slide 128:The purpose of a root-end filling is to establish a seal between the root canal space and the periapical tissues According to Gartner and Dorn, a suitable root-end filling material should be: (1) Able to prevent leakage of bacteria and their by-products into the periradicular tissues (2) Nontoxic (3) Noncarcinogenic (4) Biocompatible with the host tissues (5) Insoluble in tissue fluids (6) Dimensionally stable (7) Unaffected by moisture during setting (8) Easy to use (9) Radiopaque and not stain tissue (tattoo) 1 October 2009 128


Root Canal Filling Materials :Root Canal Filling Materials Amalgam Gutta Percha & Silver Cones Zinc Oxide Eugenol Cements IRM Super EBA Glass Ionomer Cements Polyvinyl Resins (Diaket) MTA Composite Resins and Resin Ionomer Hybrids Retroplast Resin Ionomer Suspension (Geristore) and Compomer (Dyract) 1 October 2009 129


Amalgam :Amalgam Farrar was the first to use Amalgam It is well documented that amalgam is no longer considered an appropriate material for use as a root end filling It can be difficult to handle and it is not uncommon to see particles of amalgam alloy in the tissues surrounding the root end Amalgam is prone to corrosion Disintegration and release of metal particles into the surrounding tissue 1 October 2009 130


IRM :IRM 75% ZOE, 25% Polymethacrylte 99% Eugenol, 1% Acetic acid Seals better than amalgam Not affected by liquid powder ratio or root conditioning Well tolerated by periradicular tissues Does not form any hard tissue barrier 1 October 2009 131


Super EBA :Super EBA 60% ZnO, 34% Al.Oxide & 6% Resins 37.5% Eugenol & 62.5% O-ethoxybenzoic acid Two forms – Regular & Fast set Radiopaque material, seals similar to IRM, better than amalgam Well tolerated but has shown to disintegrate in acidic pH No hard tissue formation is seen 1 October 2009 132


GIC :GIC Consists of polymeric aqueous compounds Seal and marginal sealing of light cure GIC is better than of conventional GIC GIC is susceptible to moisture attack and this has a bearing on the material Tissue response is favaourable Cytotoxicity of light cure GIC does not differ from IRM or Super EBA 1 October 2009 133


Diaket :Diaket Polyvinyl Resin Root canal sealer 98% ZnO & 2% Bismuth phosphate Liquid – Dihydroxy dichlorodiphenyl methane Superior sealing ability Toxicity has been an issue Generated long term cytotoxic tissue response and evoked an inflammatory reaction 1 October 2009 134


MTA :MTA Mineral trioxide aggregate was developed by Torabinejad and associates at Loma Linda University Main molecules present in MTA are calcium and phosphorous ions, derived from tricalcium silicate, tricalcium aluminate, tricalcium oxide, and silicate oxide Its pH, when set, is 12.5 and its setting time is 2 hours and 45 minutes Compressive strength of MTA is 40 MPa immediately after setting and increases to 70 MPa after 21 days. The result of solubility testing of MTA (ADA specification #30) indicated an insignificant weight loss following testing 1 October 2009 135


Slide 136:Mineral trioxide aggregate has been extensively evaluated for microleakage (dye penetration, fluid filtration, bacterial leakage), marginal adaptation (SEM), and biocompatibility (cytotoxicity, tissue implantation, and in vivo animal histology) The sealing ability of MTA has been shown to be superior to that of Super-EBA , IRM, GIC and was not adversely affected by blood contamination Its marginal adaptation was shown to be better than amalgam, IRM, or Super-EBA 1 October 2009 136


Slide 137:MTA has also been shown to be less cytotoxic than amalgam, IRM, or Super-EBA Animal usage tests in which MTA and other commonly used root-end filling material were compared have resulted in less observed inflammation and better healing with MTA In addition, with MTA, new cementum was observed being deposited on the surface of the material 1 October 2009 137


Conclusion :Conclusion 1 October 2009 138


References :References Pathways of Pulp (9th Ed.) – Stephen Cohen Surgical Endodontics – J.L. Gutmann Endodontics 6 – John Ingle Endodontic Therapy (5th Ed.) - F.S. Weine Advanced Endodontics – John S Rhodes Atlas of Endodontics – William T Johnson Dental Clinics of North America – 2002 Journal of Endodontics – 1995, 2002, 2003,2005, 2007 1 October 2009 139


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