Ultrasonics for periodontal therapy: evidence, Eras and formulas for success.
The impact of ultrasonic technology on clinical practice has been profound. Performed well, ultrasonic instrumentation can contribute to therapeutic gains. (1) On the other hand, history has shown that incomplete instrumentation not only jeopardizes success but can lead to complications that hasten destruction. In light of research on the systemic effects of inflammation and periodontal pathogens, clinicians must combine meticulous technique with critical thinking to insure the best clinical outcomes.
The role of the dental hygienist is destined to evolve, given the many health implications of inflammation that periodontal medicine has already established. Ramifications of oral systemic links make it critical that clinicians undertake patient care with skill and also accountability. More importantly, a perceptive, analytical mind must be maintained to assess the effectiveness of treatment rendered.
Eras and Ideology
The first commercial device for calculus removal, launched in 1957, paved the way for ultrasonic technology to impact nonsurgical therapy. (2) Shifts in theory and practice, in step with prevailing clinical judgment, have made substantial contributions--good and bad--to the periodontal status of patients being treated and maintained. An overview of the role each assumption and its equivalent methodology has played in therapy outcomes is central to objectively assess what works, what doesn't and, most importantly, why.
The challenge of nonsurgical therapy was far greater when choices in hand/manual instruments capable of accessing root contours were limited. Gracey curets used during the 1970s enabled greater root planing efficacy in deep pockets and morphologic contours. Technique consisted of heavy force directed laterally with repeated coronal pull strokes to achieve the goal of glass-like root-surface smoothness. (3) With scaling that removed all embedded calculus in the cementum, the "glassy-smooth" era was highly effective at treating infection in overlying soft tissue. (4) However, performed too aggressively or repeated during long-term maintenance, this technique resulted in removal of tooth structure. (5)
This technique unintentionally led to hypersensitive roots from repeated scaling and gradual tooth structure loss, often to the point that teeth took on an hourglass form. (6) Pain and sensitivity following therapy became a Catch-22 with patients' inability to tolerate not only maintenance instrumentation, but at times their own toothbrush, causing more deposit to form, which would make their next maintenance appointment worse. (7) Treating patients who were in chronic discomfort made desensitization therapy integral to continuing care. (8) The lesson from this era would eventually push the theory pendulum far to the opposite extreme, but nonetheless, it was indelible:
Over time, root surface overinstrumentation leads to irreversible loss of tooth structure, accompanying hypersensitivity, and an adverse condition in which patients needlessly suffer.
"Gross Scale/Fine Scale"
Ultrasonic instrumentation in this era was a preliminary measure prior to definitive hand scaling and root planing. Clinicians had previously relied on chisels and hoes to break up heavy ledges of calculus; files and sickles eliminated the bulk of deposit before following with assorted curets and Gracey curets to root plane. The ultrasonic device was a welcome adjunct for speeding the process while alleviating some of the physical demands of practice.
The bulk of original insert tips prevented insertion to the full depth of deeper pockets, leading clinicians to adopt an approach of gross scaling with power, then reappointing the patient for fine scaling using hand instruments. An advantage of this method was reduced hemorrhage and thus improved vision, but problems inherent to the approach emerged with the associated tightening of soft tissue at the gingival margin and cuff. Once superficial calculus had been removed with the ultrasonic, resulting shrinkage of the gingival tissues interfered with insertion of the instrument for subsequent fine scaling. Access to the most critical sites of infection at the base of pockets, where thorough deposit removal is most needed, became more difficult and often impossible.
Consequences of the two-stage approach eventually surfaced as a rise in abscess formation in patients who had received initial debridement with an ultrasonic scaler followed by definitive hand scaling and root planing. Clinicians who were critically evaluating patient outcomes could see the cause and effect relationship of the two procedures, but it was many years before the notion of iatrogenic abscess formation following initial gross scaling made its way to the literature. The era of "initial debridement/gross scaling" thus offered a valuable lesson:
Whether a quadrant, a sextant or one tooth, treat only what can be completed in a given session and scale to completion.
The Anesthesia Obstacle
Access to infection/calculus/biofilm was also a predicament for dental hygienists practicing in states with no provision for administration of local anesthesia. With a large retirement population ready candidates for nonsurgical periodontal therapy, Florida became the birthplace of an innovative approach using ultrasonics. The standard bulky tips available at that time were modified by grinding them down with sharpening stones to half their width or less by creative, resourceful clinicians motivated to solve the deep pocket access dilemma. (9) Once modified, power had to be set to low in order to prevent tip fracture. Thin tips used at low power simultaneously addressed both problems: access to the depths of diseased pockets and the obstacle of discomfort felt by patients. (10)
This approach attracted an enthusiastic following and was coincidentally in sync with a new theory of practice in which the goal of producing glassy-smooth root surfaces was abandoned. (11) A term introduced in textbooks and journals--"debridement"--began to substitute for "scaling and root planing." Once research had established that endotoxin did not permeate into the cementum, (12), (13) the long-standing goal of removing "altered" cementum was discarded. (14) In light of concern over root structure damage from overinstrumentation, the new goal of preserving cementum made thin-tipped ultrasonics seem preferable to bladed hand instruments. (15) The "paradigm shift" over to thin-tipped/low-powered debridement ("TTLPD") with limited, if any, hand instrumentation became a therapeutic Renaissance, and the authors, educators and practitioners promoting it considered themselves to be enlightened. (16)
TTLPD served another purpose in eliminating obstacles for clinicians in states with no local anesthesia provision. With calculus believed to be only secondary to disease and therefore inconsequential, therapy now centered on the benefits and value of the acoustic turbulence and microstreaming, cavitation and lavage that ultrasonic therapy provided. (17) Patients could better tolerate treatment at low power settings without anesthesia, and longstanding concern over removing every speck of calculus could be dismissed.
Dental hygienists trained in local anesthesia working in states that permitted administration had a different perspective. After years of experience performing definitive periodontal therapy with block anesthesia they were convinced of the relationship of calculus to disease and bone loss. They continued to maintain that roots must be free of all calculus and eventually became regarded as out of touch with contemporary theory and practice. Controversy over cementum removal by hand instruments and overinstrumentation in general was a point of contention between "old-school" traditionalists able to anesthetize patients and "progressive" practitioners embracing the new paradigm of TTLPD.
The mid-1980s paradigm shift asserted biofilm and free-flowing planktonic bacteria as the source of infection in the periodontium and believed it could be treated effectively with low-powered ultrasonics. Cavitation, acoustic turbulence and microstreaming were believed to destroy free-flowing gram-negative pathogens--not only where they made contact with the tip, but 3 mm beyond its terminal end. This hypothesis translated into the widely held belief that direct physical contact with microorganisms was not necessary for the activated tip to destroy cells.
TTLPD protocols were specific: power set to low, frequency adjusted on manually tuned units, water spray set to fine mist, insertion in the subgingival space, and rapidly moving activation strokes in random scribble patterns with the lightest contact possible. This approach effectively preserved cementum and protected roots from the destructive overinstrumentation that had been a hallmark of the glassy-smooth era. It was believed that cavitation, acoustic turbulence, lavage and microstreaming during ultrasonic instrumentation produced the desired treatment result.
Therapeutic benefits of the ultrasonic now superseded conventional mechanical therapy goals that had focused on total calculus removal. (18) Traditional goals to prepare a surface free of contaminants using bladed hand instruments and ultrasonics had relied on subjective tactile assessment with smoothness as a gauge. Advocates of TTLPD who embraced the paradigm shift rejected the idea of root smoothness as a measure of completion since they did not interpret calculus as significant to clinical end goals. (19) They instead focused on the tissue response following therapy as a measure of success: (20) Bleeding that temporarily or partially subsided along with partial improvement in tissue form and tone was thought to be indicative of success. (21)
Final Verdict on Calculus
Nearly a generation of practitioners has been influenced by and/or applied the principles of TTLPD as an approach to treatment before the development of the endoscope in 1999 could verify the negative influence of partially scaled, residual and burnished calculus to the disease state. (22), (23), (24) Biofilm research, along with published findings of clinicians performing periodontal endoscopy, has made a profound contribution to our knowledge of what instrumentation must accomplish for infection to resolve. (25) The endoscope eliminates all past and current speculation on how thorough calculus removal must be, and the evidence clearly indicates "calculus matters," whether a mere fraction of a millimeter or a ledge. (26) Burnished calculus in particular becomes evenly smooth, leading the clinician assessing by tactile means to assume it is no longer present.
Burnishing is most prevalent with low-powered ultrasonic instrumentation, which leaves the outer layers of deposit polished until it is a thin, compacted and densely smooth veneer. Dull bladed instruments and/or inadequate lateral pressure on the stroke also contribute to calculus being burnished. Both methods can result in burnishing--however, just as high-powered ultrasonic scaling is faster at heavy calculus removal than hand instruments, low-powered ultrasonic scaling is faster at burnishing calculus. Most critical to know and apply is that any calculus, burnished or not, serves as a mineralized reservoir and scaffold for the biofilm permeating its layers. Therapeutic measures using locally applied antimicrobials or ultrasonics will permit an initial healing response that will appear to indicate success. However, if any calculus is left behind, a lesion in the soft tissue overlying the deposit will remain, thus sustaining infection. The endoscope has shown consistent recolonization of biofilm on the surface of burnished calculus within days following instrumentation, with the lesion in the overlying soft tissue corresponding exactly to the shape of the deposit in every case. The lessons here are unequivocal:
For the infection in a periodontal lesion to resolve, root surfaces must be free of contaminants--meaning all calculus must be removed by means of physical contact/disruption, covering every square millimeter to include attached biofilm. Definitive instrumentation performed without anesthesia can severely compromise the expected results of initial root preparation.
The success of initial therapy depends upon access for instrumentation to achieve the standard of comprehensive coverage. (27) It is the professional and ethical obligation of the hygienist to provide treatment that is thorough and comfortable, but the patient's inflammatory state hinders this goal. Since soft tissue anesthesia alone is usually inadequate for thorough removal of embedded calculus, optimum access and comfort must be insured by the use of local anesthesia.
The hygienist should not compromise treatment quality because of a reluctance to give anesthesia. Planning a future second appointment to remove residual calculus after bleeding and inflammation have subsided follows the gross scale/fine scale model, shown to be flawed and long discarded. This two-stage approach makes the access needed for complete deposit removal even less likely to be achieved. If unable by law to administer local anesthesia, the hygienist must request that the dentist anesthetize the patient. When injections are not possible due to medical conditions, subgingival local anesthetic gel (Oraqix[R]--available from Dentsply) or subgingival topical anesthetics can be used as a substitute.
(1.) Loos B, Kiger R, Egelberg J. An evaluation of basic periodontal therapy using sonic and ultrasonic scalers. J Clin Periodontol. 1987; 14:29-33.
(2.) Johnson WN, Wilson JR. The application of the ultrasonic dental unit to scaling procedures. J Periodontol. 1957; 28: 264-71.
(3.) Lie T, Meyer K. Calculus removal and loss of tooth substance in response to different periodontal instruments: a scanning electron microscope study. J Clin Periodontol. 1977; 4(4): 250-62.
(4.) Jones WA, O'Leary TJ. The effectiveness of root planing in removing bacterial endotoxin from the roots of periodontally involved teeth. J Periodontol. 1978; 49: 337-42.
(5.) Ritz L, Hefti AF, Rateitschak KH. An in vitro investigation on the loss of root substance in scaling with various instruments. J Clin Periodontol. 1991; 18(9): 643-7.
(6.) Rateitschak-Pluss EM, Schwarz JP, Guggenheim R, et al. Non-surgical periodontal treatment: where are the limits? an SEM study. J Clin Periodontol. 1992; 19(4): 240-4.
(7.) Fukazawa E, Nishimura K: Superficial cemental curettage: its efficacy in promoting improved cellular attachment on human root surfaces previously damaged by periodontitis. J Periodontol. 1994; 65(2): 168-76.
(8.) Lawson K, Gross KB, Overman PR, Anderson D. Effectiveness of chlorhexidine and sodium fluoride in reducing dentin hypersensitivity. J Dent Hyg, 1991; 65(7): 340-4.
(9.) Holbrook T, Low S. Power-driven scaling and polishing instruments. In: Harden JF, ed. Clark's clinical dentistry. St. Louis, Mo.: Mosby Yearbook; 1991:1-24.
(10.) Dragoo MR. A clinical evaluation of hand and ultrasonic instruments on subgingival debridement: part I. with unmodified and modified ultrasonic inserts. Int J Periodont Rest Dent 1992; 12(4): 311-23.
(11.) O'Leary TJ. The impact of research on scaling and root planing. J Periodontol. 1986; 57:69-75.
(12.) Hughes FJ, Smales FC. Immunohistochemical investigation of the presence and distribution of cementum-associated lipopolysaccharides in periodontal disease. J Periodont Res. 1986; 21(6): 660-7.
(13.) Moore J, Wilson M, Kieser JB. The distribution of bacterial lipopolysaccharide (endotoxin) in relation to periodontally involved root surfaces. J Clin Periodontol. 1986; 13(8): 748-51.
(14.) Nakib NM, Bissada NE, Simmelink JW, et al. Endotoxin penetration into root cementum of periodontally health and diseased human teeth. J Periodontol. 1982; 53: 368.
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(16.) Drisko CL. Periodontal debridement: hand versus power-driven scalers. Dental Hygiene News. 1995; Spring: 78-83.
(17.) Khambay BS, Walmsley AD. Acoustic microstreaming: detection and measurement around ultrasonic scalers. J Periodontol. 1999; 70(6): 626-31.
(18.) Kepic TJ, O'Leary TJ, Kafrawy AH. Total calculus removal: an attainable objective? J Periodontol. 1990; 61: 16-20.
(19.) Hawkins P. Micro ultrasonics: contemporary periodontal instrumentation. Access. Jul 1996; 25-8.
(20.) Joss A, Adler R, Lang NP. Bleeding on probing. a parameter for monitoring periodontal conditions in clinical practice. J Clin Periodontol. 1994; 21(6): 402-8.
(21.) Lang NP, Adler R, Joss A, Nyman S. Absence of bleeding on probing, an indicator of periodontal stability. J Clin Periodontol. 1990;17(10): 714-21.
(22.) Fujikawa K, O'Leary TJ, Kafrawy AH. The effect of retained subgingival calculus on healing after flap surgery. J Periodontol. 1988; 59: 170-5.
(23.) Wilson TG, Harrel SK, Nunn ME, et al. The relationship between the presence of tooth-borne subgingival deposits and inflammation found with a dental endoscope. J Periodontol. 2008; 79(11): 2029-35.
(24.) Checchi L, Montevecchi M, Checchi V, Zappulla F. The relationship between bleeding on probing and subgingival deposits: an endoscopic evaluation. Open Dent J. 2009; 28: 154-60.
(25.) Stambaugh RV. A clinician's three year experience with perioscopy. Compend Contin Educ Dent. 2002; 23: 1061-70.
(26.) Pattison A, Pattison G. Periodontal instrumentation transformed. Dimensions of Dental Hygiene. 2003; 1(2): 18-20, 22.
(27.) Brayer WK, Mellonig JT, Dunlap RM, et al. Scaling and root planing effectiveness: the effect of root surface access and operator experience. J Periodontol. 1989; 60: 67-72.
Stacy A. Matsuda, RDH, BSDH, is a clinical instructor at Oregon Health and Science University School of Dentistry and has been in periodontal practice over 30 years. She is co-author with Anna M. Pattison, RDH, MS, of the upcoming third edition of Periodontal Instrumentation and contributed four chapters to the 10th edition of Clinical Practice of the Dental Hygienist by Esther M. Wilkins, RDH, DMD. A frequent presenter, she also directs Pacific NW Institute, working with faculty and clinicians to advance the standard of care in nonsurgical therapy through tailored hands-on courses and faculty development programs. Ms. Matsuda has published numerous peer-reviewed articles on periodontal instrumentation and serves as an editorial advisory board member for Dimensions of Dental Hygiene. She can be reached at stacymatsuda-RDH@comcast.net.
This column was made possible by an educational grant sponsored by Hu-Friedy Mfg. Co., Inc.
By Stacy Matsuda, RDH, BSDH
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|Date:||Sep 1, 2010|
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