Microsurgical instruments

micro surgical instruments in endodontics

1. MICROSURGICAL INSTRUMENTS -POOJA JAYAN

2. CONTENTS INTRODUCTION COMPARISON BETWEEN TRADITIONAL AND MICROSURGICAL APPROACHES PRINCIPLES AND CONCEPTS OF MICROSURGERY RATIONALE AND OBJECTIVE CLASSIFICATION OF MICROSURGICAL CASES INDICATIONS FOR ENDODONTIC MICROSURGERY CONTRA-INDICATIONS FOR ENDODONTIC MICROSURGERY CLASSIFICATION OF ENDODONTIC MICROINSTRUMENTS Examination instruments Incision and elevation instruments Tissue retraction instruments Osteotomy instruments Curettage instruments Inspection instruments Ultrasonic Units and Tips for Root End Preparation Microplugger instruments Suturing instruments Miscellaneous instruments CONCLUSION REFERENCES

3. INTRODUCTION Microsurgery is broadly defined as “surgery performed under magnification provided by the microscope ” 1 . In 1921, Carl Nylen who is considered as the father of microsurgery first used a binocular microscope to correct otosclerotic deafness. Apotheker and Jako first introduced the microscope to dentistry in 1978. It was first introduced in the branch of endodontics in 1986 . 2 Endodontic microsurgery accounts for about 3-10% of typical endodontic practice 3 . Although conventional endodontics is more and more popular, surgical endodontics has remained a difficult area associated with a high rate of failure 4 1. Daniel RK. Microsurgery: Through the looking glass. N Engl J Med 1979; 300: 1251-1257.. 2. Carr GB. Microscopes in endodontics. J Calif Dent Assoc 1992;20:55–61. 3. Abbott PVo Analysis of a referral-based endodontic practice. 2: Treatment provided. J Endod 1994;20:253 4. Kim S, Pecora G. Rubinstein RA. Color Atlas of Microsurgery in Endodontics. Philadelphia: Saunders. 2001 ;5:1-12

4. INTRODUCTION Common failures result from poor visualization that hampers treatment. Now, the microscope provides magnification and coaxial illumination, forcing the industry to develop microinstruments for working in a confined space. These include micromirrors to allow indirect work vision. Microexplorers to check for microfissures and craze lines on the resected root dentin that can spoil the prognosis of well-executed microsurgery Ultrasonic microtips to allow the making of a clean retrocavity parallel to the long axis of the root Microsyringes to dry the retrocavity . Micropluggers to condense the retrofilling material right into the retrocavity .

5. Ananad S, Soujanya E, Raju A, Swathi A. Endodontic microsurgery: An overview. Dentistry and Medical Research. 2015 Jul 1;3(2):31.

6. PRINCIPLES AND CONCEPT OF MICROSURGERY The principles of microsurgery are an amplification of those applicable to any general surgical procedures. Of prime importance are gentle handling of tissues and passive wound closure aiding in primary uneventful healing, making the procedure more acceptable. The concept of microsurgery is based on three important elements which form the microsurgical triad that includes magnification, illumination and instruments.

7. RATIONALE AND OBJECTIVE RATIONALE To remove the causative agent of peri-radicular pathology. To restore the periodontium to a state of biological and functional health. OBJECTIVE To ensure the placement of a proper seal between the periodontium and the root canal foramina.

8. CLASSIFICATION OF MICROSURGICAL CASES Kim and Kratchman   classified periradicular lesions into categories A-F. Lesion Types A, B, and C represent lesions of endodontic origin and are ranked according to increasing size of periradicular radiolucency. Lesion Types D, E, and F represent lesions of combined endodontic-periodontal origin and are ranked according to the magnitude of periradicular breakdown. Class A represents the absence of a periapical lesion, no mobility, and normal pocket depth, but unresolved symptoms after nonsurgical approaches have been exhausted. Clinical symptoms are the only reason for the surgery. Class B represents the presence of a small periapical lesion together with clinical symptoms. The tooth has normal periodontal probing depth and no mobility. The teeth in this class are ideal candidates for microsurgery. Class C teeth have a large periapical lesion progressing coronally, but without periodontal pocket and mobility. Class D are clinically similar to those in Class C, but have deep periodontal pockets. Class E teeth have a deep periapical lesion with an endodontic-periodontal communication to the apex but no obvious fracture. Class F represents a tooth with an apical lesion and complete denudement of the buccal plate but no mobility. Classes A, B, and C present no significant treatment problems, and the conditions do not adversely affect treatment outcomes. Classes D, E, and F present serious difficulties.

9. Indications for Endodontic Microsurgery Adequately executed endodontics but failed with a persistent periapical radiolucent lesion Adequately executed endodontics with constant pain with or without swelling Apical transportation, ledges and other iatrogenic problems with persistent pathology and symptoms Tooth with a large post and crown restoration completed, especially maxillary anterior teeth Calcified canals with or without symptoms and PAR (periapical radiolucency) Broken instrument in apical half of the root Failed traditional surgery Overfilled canal with PAR Complex/compound apical curvatures that are inaccessible from an orthograde approach

10. Contra-Indications for Endodontic Microsurgery General Medically compromised patients Emotionally distressed patients Lack of operation skill and experience Local Localized acute inflammation Inaccessible surgical site Teeth with poor prognosis

11. INSTRUMENTS Proper instrumentation is fundamental for microsurgical intervention. As the instruments are primarily manipulated by the thumb, index and middle finger, their handles should be round, yet provide traction so that finely controlled rotating movements can be executed. The rotating movement of the hand from two o’clock to seven o’clock (for right-handed persons) is the most precise movement the human body is able to perform. The instruments should be approximately 18 cm long and lie on the saddle between the operator’s thumb and the index finger. They should be slightly top-heavy to facilitate accurate handling. In order to avoid an unfavorable metallic glare under the light of the microscope, the instruments often have a color coated surface. The weight of each instrument should not exceed 15–20 g (0.15–0.20 N) in order to avoid hand and arm muscle fatigue.

12. KiS set from Obtura /Spartan Jet Microsurgical kit from B&L Biotech Co.

13. CLASSIFICATION (By Kim et al)

14. EXAMINATION INSTRUMENTS The examination instruments include the dental mirror, periodontal probe, endodontic explorer, and microexplorer . Only the microexplorer is specifically designed for microsurgery. It has a 2-mm tip bent at 90 degrees on one end and 130 degrees on the other. The short tip makes it particularly easy to maneuver inside the small boney crypt. This instrument is extremely useful for locating an area of leakage on the resected root surface and for distinguishing a fracture line or canal from an insignificant craze line. A tip of a microexplorer points to the unfilled canal space on a resected root surface.

15. INCISION & ELEVATION INSTRUMENTS Instruments used for incision and elevation include a 15C blade and handle and soft tissue periosteal elevators. The ideal scalpel blade for microsurgery is a 15C blade, which is small enough to manage the interproximal papilla but large enough to make a vertical releasing incision in one stroke. Microblades are useful only when the interproximal spaces are tight. The soft tissue elevators are designed to elevate the gingiva and tissue from the underlying cortical bone with minimal trauma to the tissue. one end of the instrument has a thin, sharp, triangular beak and the other end has a sharp, rounded beak that varies in size. Unlike the periosteal elevators used in periodontics, this new design incorporates thin edges and points that allow the soft tissue to be elevated from the bone cleanly and completely. Periosteals Molt 9, minimolt , Prichard PPR3, PPB user, P145S, P9HM, P4 elevators are also used.

16. TISSUE RETRACTION INSTRUMENTS The new retractors developed for microsurgery eliminate many deficiencies of previous traditional retractors, which are basically unfit to microsurgery. KimTrac retractors have more variable widths than other conventional retractors (from 8 mm to 14 mm compared with conventional 10 mm) KimTrac P1 and P2 retractors have wings to separate the elevated soft tissue from the area of surgery and an additional plastic protector for soft tissue elevation.

17. TISSUE RETRACTION INSTRUMENTS KimTrac can be used with and without a plastic protector. However, the plastic protector is advantageous as it ensures easy flap retraction with highly improved visibility and accessibility to the operating field . Unlike other products with blunt ends, the KimTrac is able to anchor against the cortical boney plate precisely and stably, regardless of whether the shapes are plain or protrusive, due to its serrated end. Comparison of the thickness of blades of retractors shows that the KimTrac retractor is one-third the thickness of other retractors, making them an ideal retractor using the bone grooving technique on mandibular posterior surgery.

18. TISSUE RETRACTION INSTRUMENTS The Kim/Pecora (KP 1, 2, and 3) retractors (Obtura/Spartan) also have wider tips than conventional retractors (15 mm compared with 10 mm) and are 0.5 mm thinner Their serrated ends anchor the retractors securely on to the bone. The KP 4 retractor is a small, all-purpose retractor with the same features as the others but has the standard 10-mm width. The KP retractor tips are modeled to the concavities and convexities of the cortical boney plate. Using an endodontic retractor on a convex or flat bone surface is difficult. The contact with the bone is limited to a very small area; in contrast, the KP 1, KP 2, and KimTrac M5 retractors fit the convex contour of the bone. The full contact of the retractor tip on the bone provides a secure, stable hold, eliminating sudden or creeping slippage that results in traumatized tissue, swelling, and painful healing. It also eliminates interference and interruption during the surgery and assistant fatigue. Many retractors are available on the dental market like Rubinstein retractors, Prichard retractors , Minnessotta retractor, weider retractors, Cat’s Perr retractors.

19. OSTEOTOMY INSTRUMENTS A 45-degree surgical handpiece - The Impact Air 45 handpiece with a Lindemann bur is the instrument of choice for this procedure (Brasseler NSK and Morita) It is designed to direct water on to the cutting surface by channeling it along the surface of the bur while the air is ejected through the back of the handpiece This reduces the chance of emphysema and pyemia and creates less splatter than a conventional handpiece. The handpiece’s 45-degree angled head makes it easier to work in and visualize difficult to reach areas. The H 161 Lindemann bone cutting bur is used for osteotomies and has fewer flutes than conventional burs, resulting in less clogging and frictional heat and more efficient cutting. Other burs are #702 tapered fissure bur, #6 & #8 round bur, multipurpose burs, multifluted carbide finishing burs, surgical length plain fissure bur.

20. CURETTAGE INSTRUMENTS Complete curettage of granulation tissues from an osteotomy site is probably the hardest part of the surgery. Curettage instruments include periodontal curettes, surgical curettes, and miniendodontic , minimolt curettes, Columbia 13-14, minijacquette 34/35 scalers. Curettage generally is not a microsurgical procedure and any periodontal curette can be used for that purpose.

21. INSPECTION INSTRUMENTS Micromirrors are available in many different shapes. An important feature of the mirror neck is flexibility. Without the ability to bend the micromirror neck to accommodate the angle, the resected root surface could not be viewed clearly or completely. It has shown rectangular mirrors with 2 mm, 3 mm, and 4mm widths on a flexible stainless handle are the micromirrors of choice. A round mirror has limited usage on a round resected root surface, e.g., central incisors.

22. Ultrasonic Units and Tips for Root End Preparation One of the most significant advancements in endodontic microsurgery is the piezoelectric ultrasonic instrument for root end preparation. ULTRASONIC UNITS: Ultrasonic units create vibrations in the range of 30 to 40 kHz by exciting quartz or ceramic piezoelectric crystals in the handpiece. The energy created is carried to the ultrasonic tip, producing forward and backward vibrations in a single plane. Continuous irrigation along the cutting tip cools the surface and maximizes debridement and cleaning. The three most widely used ultrasonic units are the EMS, the Spartan (Spartan/Obtura), and the P-5 (Acteon). It is strongly advised to have a unit that has both Piezotome for Groove preparation and ultrasonic root end preparation. Currently, Acteon P-5 has both capabilities.

23. ULTRASONIC TIPS: The first ultrasonic tips for endodontic surgery were stainless steel Carr Tips (CT 1–5) in 1990. Surgical ultrasonic tips, first designed by Dr. Garry Carr are known as Carr tips or CTs. They are 1/4 mm in diameter and about 1/10 the size of a conventional microhead handpiece. The CT 1 and CT 5 have the same design except that the CT 5 tip is more sharply pointed. The hook-shaped tip, known as a back-action or CK tip, is very effective for cleaning the buccal wall of a canal. The CT 1 and CT 5 tips are used mainly for maxillary and mandibular anterior teeth. The CT 2 and CT 3 have a double angle to facilitate work in posterior teeth. In 1999 Spartan/Obtura introduced KiS (Kim Surgical) tips. The KiS ultrasonic tips have a better cutting ability and a more efficient irrigation port. They are coated with zirconium nitride and have an irrigation port near the tip rather than along the shaft.

24. ULTRASONIC TIPS: These advanced tips cut faster and smoother and cause fewer microfractures because of the improved positioning of the irrigation port. The KiS 1 tip, which has an 80 degree angle and is 0.24 mm in diameter, is designed for the mandibular anterior teeth and premolars. The KiS 2 tip has a wider diameter tip and is designed for wider teeth (e.g., maxillary anteriors ). The KiS 3 tip is designed for posterior teeth. It has a double bend and a 75 degree angled tip for use in the maxillary left side or the mandibular right side. The KiS 4 tip is similar to the KiS 3 except that the tip angle is 110 degrees, to reach the lingual apex of molar roots. The KiS 5 tip is the counterpart of the KiS 3 for the maxillary right side and the mandibular left side. The KiS 6 tip is the counterpart of the KiS 4 tip

25. JETips Recently Jet Tips were introduced. A special feature of this tip is microprojection of the cutting surface, allowing quick and complete removal of gutta percha from the canal. They have bendable ultrasonic tips (B&L Biotech) which the operator can bend in any direction for better access. JETips are available with 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm tips that allow for bending with a tip bending jig that will provide a customized tip angle to meet all microsurgical needs.

26. STROPKO IRRIGATOR/DRIER This simple but useful device fits on a standard air/water syringe and uses blunt 0.5-mm diameter microtips. It is easy to use and highly effective for irrigating and drying retropreparations and resected root surfaces. It supplants the use of paper points to dry the preparation, which provides no certainty that the preparation is completely dry.

27. MICROPLUGGER INSTRUMENTS After placement of MTA or Bioceramic putty into the root end preparation using the Lee carver, the filling materials need to be gently condensed to fill the whole root end preparation length of 3mm or a longer length. This procedure is done using micropluggers , one a thin 2-mm diameter and another a thick 4-mm diameter depending on the size of root end preparation.

28. SUTURING INSTRUMENTS The Laschal microscissors , or any small-beaked scissors, and the Castroviejo needle holder are used to manage 5-0 or 6-0 synthetic sutures . These two instruments are recommended because standard large-beaked scissors do not cut well enough and are too large in a microsurgical environment. Other needle holders are also too large for microsurgery. The smaller, more delicate Castroviejo needle holder may require some adjustment at first but will reward the surgeon with greater ease in delicate and difficult suturing. Before the advent of microsurgery, 4-0 silk sutures were the standard for endodontic surgery, but they are no longer recommended. Because silk sutures are braided and thick, plaque, food debris, and bacteria readily accumulate on them, resulting in secondary inflammation at the suture site. To prevent this inflammation and associated delayed healing, 5-0 and 6-0 monofilament sutures of nylon or polypropylene are now used. Suture needles with a triangular cross-section for easy penetration of the tissue and 1/2 and 3/8 curvatures are recommended

29. MISCELLANEOUS INSTRUMENTS A number of miscellaneous instruments are used in endodontic microsurgery. A large ball burnisher and a bone file are used to smooth the bone and root surface and to mold bone augmenting material to the boney contours. A small rongeur is used to remove granulation tissue. The beaks of these rongeurs are miniaturized to fit into the hard to reach areas deep inside the boney crypt. Dental cart - The cart is a compact, all in one unit with the essentials built in. It has a tank for sterilized water high and low-speed handpiece ports, an ultrasonic unit, and a Stropko irrigator/drier. This cart is an important piece of equipment for a modern microsurgery practice.

30. Conclusion Microsurgery has made a great difference in all surgical fields due to its desirable qualities of obtaining cleaner incisions, reduced hemorrhage, reduced trauma at the surgical site and closer wound apposition. Since the surgical procedure is less traumatic and less invasive, healing occurs by primary intention which is rapid with minimal granulation tissue or scar tissue. Within 48 hours vascular anastomosis has been observed in the healing tissues with reduced pain and inflammation. Therefore the end-point appearance of the tissues is superior, hence, making microsurgery a preferable option.

31. REFERENCES Daniel RK. Microsurgery: Through the looking glass. N Engl J Med 1979; 300: 1251-1257. Carr GB. Microscopes in endodontics. J Calif Dent Assoc 1992;20:55–61. Abbott PVo Analysis of a referral-based endodontic practice. 2: Treatment provided. J Endod 1994;20:253 Kim S, Pecora G. Rubinstein RA. Color Atlas of Microsurgery in Endodontics. Philadelphia: Saunders. 2001 ;5:1-12 Ananad S, Soujanya E, Raju A, Swathi A. Endodontic microsurgery: An overview. Dentistry and Medical Research. 2015 Jul 1;3(2):31. Baek S, Kim S. Microsurgical Instruments. Microsurgery in Endodontics. 2017 Sep 15:9-23. Akbari G, Prabhuji ML, Lavanya R. MICROSURGERY: A CLINICAL PHILOSOPHY FOR SURGICAL CRAFTSMANSHIP. E-Journal of Dentistry. 2012 Jul 1;2(3). Merino EM. Endodontic microsurgery. London: Quintessence; 2009 Mar.