Effect of Waterlase laser retrograde root-end cavity preparation
Effect of Waterlase laser retrograde root-end cavity
preparation on the integrity of root apices of extracted teeth as demonstrated
by light microscopy
James A. Wallace, DDS, MDS, MSD, MS
School of Dental Medicine, University of Pittsburgh,
Pittsburgh, Pennsylvania, USA
apical preparations, root-end cracks, root-end
preparatioans, Waterlase laser. Most endodontists use
ultrasonic instruments for retrograde root-end cavity preparations even though
they have been found to produce cracks. In this labo
ratory study, thirty-six randomly chosen roots had root-end
cavity preparations
Dr James A. Wallace, School of Dental Medicine,
made with the Waterlase laser and only one questionable
intra-canal crack was
University of Pittsburgh, 3501 Terrace Street,
found. It was concluded that the Waterlase laser when used
to make endodontic
3064 Salk Annex, Pittsburgh, PA 15261, USA.
root-end cavity preparations produces either no cracks, or
a very low percentage
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(2.8%) of cracks.
doi: 10.1111/j.1747-4477.2006.00006.x
Introduction
Most endodontists consider ultrasonics as the
method of choice for retrograde root-end cavity preparation. Several authors
have found ultrasonic root-end cavity preparation produces cracks and/or
chipping. (Table 1).
The Biolase Waterlase (Biolase ® Technology, Inc. San Clemente,
CA, USA) Er-Cr:YSGG (Erbium, Chromium: Yttrium, Scandium, Gallium and Garnet)
pulsed laser has been found to be useful in endodontic surgery for root-end
resection, root-end cavity preparation, haemostasis, and sterilization of the
root apex and surrounding tissue. For restorative procedures, laser use has
increased patient acceptance related to pain, vibrations, whine of the drill,
micro-fractures and heat production (15). This laser cuts hard tissue with
highly energised water particles and soft tissue directly with laser energy.
(15) Preliminary studies looking at the safety and efficacy of using the
ErCr:YSGG laser found it to be a proficient instrument in cutting bone.
(16) FDA approval for apicoectomy surgery was granted on 12
February 2002 and flap surgery on 3 February 2003. Gouw-Soares (17) demonstrated
the Er:YAG (Erbium:Yttrium-Aluminium Garnet), Ga-Al-As (Gallium Aluminium
Arsenide) and Nd:YAG (Neodymium: Yttrium-Aluminium Garnet) lasers, when used in
combination for performing an apicoectomy,
produced heat which may lead to cracking. Root-end cavity preparation should be
three millimetres in depth and the resection angle should be zero (18,19).
The purpose of this study was to determine if root-end
preparations at a depth of three millimetres in resected roots at a zero angle
performed by the Waterlase laser produce cracks and/or chipping. To the author’s
knowledge there is no published data on the use of the Waterlase laser for this
purpose.
Materials and methods
Seventeen extracted teeth, comprising eight
mandibular molars, five maxillary molars, three bicuspids and one central incisor
were chosen at random for a total of thirty-six root apices.
The teeth were stored in 0.9% sodium chloride and 1% sodium
hypochlorite solution to preserve and inhibit microbial growth. All the teeth
apices were preoperatively evaluated by two independent investigators with a
fibre-optic translucent light source for a time period not exceeding 2 min using
a Fisher stereomicroscope (FSM) at ×40 magnification and a Global Surgical
Microscope (GSM) at ×12 magnification with digital photographs being taken at
this time (20).
Effect of Waterlase Laser J. A. Wallace et
al. Table 1 Ultrasonic and bur root-end preparation in vitro
Paper
Type of instrument
Frequency of cracks
Assessment
Abedi et al. (1)
Fissure bur and ultrasonic
Significantly more cracks with
ultrasonic versus bur
SEM
Layton et al.(2)
Ultrasonic low and high
More than 40% demonstrated
cracks
Dye and microscope
Frank et al. (3)
Bur slow and high speed, sonic
10–50% of teeth
Dye and microscope
ultrasonic medium and high
Lloyd et al. (4)
Sonic and bur
Sonic 10–15%
SEM
Bur 0–5%
Beling et al.(5)
Ultrasonic
5–10%
SEM
Min et al.(6)
Bur, ultrasonic
Bur 10%, ultrasonic 100%
Confocal microscopy
Low and high
Brent et al. (7)
Ultrasonic
20–25%
SEM
Morgan and Marshall (8)
Ultrasonic
5%
SEM
Gray et al. (9)
Bur and ultrasonic
Bur 0%
SEM
Ultrasonic 7%
Rainwater et al. (10)
Bur and ultrasonic
60–80% ultrasonic
Microscope
10% bur
Peters et al. (11)
Ultrasonic
1%
SEM
Gondim et al. (12)
Sonic, ultrasonic
18–80%
SEM
Ishikawa et al. (13)
Ultrasonic
10–20%
SEM
Khabbaz et al. (14)
Bur, sonic, ultrasonic
7–20%
Video microscope
SEM, standard error of the mean.
A three millimetre root-end resection was
made on each root apex perpendicular to the long axis using a carbide bur in a
high speed hand piece with water using GSM at ×12 magnification (21). The
resected root apex was again examined for cracks and photographed as above.
Following root resection, the teeth were immediately placed in a solution of
0.004% aqueous methylene blue dye in distilled water (2). Forty-eight hours
following immersion, two investigators independently examined the specimens
using the FSM ×40 magnification and photographed them with the GSM at ×12
magnification (2).
The root canals of the teeth used in the study were
uninstrumented and unobturated. The root-end preparations were made using the
Waterlase laser with a 600 µm laser tip and a setting of four watts, 55% water
and 65% air as suggested by the manufacturer. The tip was used 1–2 mm from the
surface using the GSM at ×12 magnification. A Class I root-end preparation was
made in the 36 resected root-ends to a depth of 3 mm and approximately 1 mm in
diameter confirmed with a periodontal probe. The root-end preparation was done by
holding the teeth in the operator’s gloved hand with the tooth surrounded by
saline-soaked gauze. The root was kept moist during preparation as energised
water molecules did the cutting. Following apical preparation the specimens were
examined and photographed with the GSM ×12 magnification (Fig. 1).
The teeth were immediately returned to the storage unit and
immersed in 0.004% methylene blue solution. The total preparation time for each
root was less than 2 min.
The teeth were then re-examined under the FSM at ×40
magnification with transillumination by two independent investigators.
Results
The 36 roots were evaluated before resection
with the GSM ×12 magnification and the FSM at ×40 magnification by two independent
investigators using transillumination for under 2 min and no cracks were
identified. Digital photographs with GSM at ×12 magnification illustrated no
cracks.
The root-ends were evaluated after resection as would be done
in a clinical surgical situation, and no cracks were evident using the GSM at
×12 magnification. Forty-eight hours following immersion in 0.004% methylene blue
dye, two investigators independently examined the resected root ends with the
GSM ×12 magnification and the FSM at ×40 magnifications with transillumination,
and once again no cracks were found.
During the root-end preparation in handling the specimens with
gloved hands no detectable heat was produced in the specimens, thus enhancing
chances for no cracks being produced. Sample specimens before and after root-end
preparation are shown in Figures 1–3.
The teeth were re-examined under the FSM at ×40 magnification
using transillumination by two independent investigators. One questionable
intracanal crack was observed in one root-end preparation (that is, in 2.8% of
specimens).
J. A. Wallace et al. Effect of
Waterlase Laser
Discussion and conclusion
Pulsed ErCr: YSGG laser energy can be used to
prepare root-ends for an apical seal. It is the energised water molecules that
do most of the cutting and thus it was found that the roots remained very cool
to the touch during preparation, as has been noted for osseous tissue (22). No
cracks were noted pre-treatment. The digital photographs with the GSM at ×12
magnification were studied and no cracks were observed. It is important to note
that this is the magnification typically used during clinical surgical
procedures. Scanning electron microscopy examination would have been useful for
closer inspection of the samples. The canals were left un-instrumented as there
was no significant difference in the incidence of root cracks when canals were
obturated or unobturated (6). Three millimetres of the root apices were removed
with a high-speed fissure bur and water under the GSM at ×12 magnification to
simulate clinical conditions and no cracks were observed. The root-end
preparations were prepared to a depth of three millimetres with the Waterlase
laser using laser settings recommended by the manufacturer. There were again no
cracks observed during or immediately after the procedure.
The thickness of remaining dentine is not of such a concern
with the laser preparation, as it would be with ultrasonic or rotary
instruments, because there is no vibration or pressure exerted during root-end
preparation that may produce cracks. Methylene blue plus transillumination with
magnification was used to detect dentinal cracks as
recommended by Wright et al. (23).
After 24 h in the methylene blue dye, the teeth were again evaluated and
photographed with the GSM ×12 magnification. They were again subjected to
transillumination and FSM at ×40 magnification and evaluated for under 2 min.
Only one questionable intracanal crack was found. This may have initially been
present but could not be detected until the root-end preparation was completed.
Connective tissue changes that occurs in response to other laser root surgery
would not occur with the Water-lase as it is the energised water that does the
cutting, not the laser. At present, no apical preparation laser micro-handpiece
is available but such an instrument is under development. Teeth in situ,
regardless of the method of root-end preparation, do not exhibit a lesser
tendency towards cracking than extracted teeth (12).
Based on this laboratory study, the Waterlase laser does not produce a
clinically relevant rate of cracking when used to make endodontic root-end
preparations. The next step is to use this laser in root-end preparations under
clinical conditions with the GSM and to record the results with digital
photographs.
Acknowledgement
The author is grateful to John R. Skoner, DMD, MDS for his
help in evaluating the samples.
Abedi HR, Van Mierlo B, Wilder-Smith P, Torabinjad M.
Effects of ultrasonic root cavity preparation on the root apex. Oral Surg Oral
Med Oral Pathol 1995; 80: 207–213.
Layton CA, Marshall JG, Morgan LA, Baumgartner JC. Evaluation
of cracks associated with ultrasonic root end preparation. J Endod 1996; 22:
157–60.
Frank RJ, Antrim DD, Bakland LK. Effect of retrograde cavity preparation on
root apices. Endod Dent Traumatol 1996;
12: 100–3.
Lloyd A, Gutmann J, Dummer P, Newcrombe R. Microleakage of Diaket and
amalgam in root-end cavities prepared using Micromega sonic retro-prep tips. Int
Endod J 1997; 30: 196–204.
Beling K, Marshall J, Morgan L, Baumgartner T. Evaluation for cracks
associated with ultrasonic root-end preparation of gutta-percha filled canals. J
Endod 1997; 23: 723–6.
Min MM, Brown CE, Legan JJ, Kofrawy AA. In vitro evaluation of effects of
ultrasonic root-end preparation on resected root surfaces. J Endod 1997; 23:
624–8.
Brent PD, Morgan LA, Marshall JG, Baumgartner JC. Evaluation of
diamond-coated ultrasonic instrumentation for root-end preparation. J Endod
1999; 25: 672–5.
Morgan LA, Marshall JG. A scanning election microscopic study of in vivo
ultrasonic root-end preparations. J Endod 1999; 21: 567–70.
Gray GS, Hatton S, Haltzman DJ, Jenkins DB, Nielsen CJ. Quality of root-end
preparation using ultrasonic and rotary instrumentation in cadavers. J Endod
2000; 26: 281–83.
Rainwater A, Jeansonne BG, Sarkaro N. Effects of ultrasonic root-end
preparation on micro-crack formation and leakage. J Endod 2000; 26: 72–5.
Peters CI, Peters OA, Barbakow F. An in vitro study comparing root-end
cavities prepared by diamond-coated and stainless steel ultrasonic retrotips.
Int Endod J 2001; 34: 142–48.
Gondim E Jr, Fiquesredo A, Ferraz CC, Teixeira FB, de Souza-Filho FJ. Effect
of sonic and ultrasonic retrograde cavity preparation on the integrity of root
apices of freshly
Ishikawa H, Sawada N, Kaybayashi C, Suda H. Evaluation of root-end cavity
preparation using ultrasonic retrotips. Int Endod J 2003; 36: 586–91.
Khabbaz MG, Kerezaudia NP, Aroni E, Tsatsas V. Evaluation of different
methods for the root-end cavity preparation. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod 2004; 98: 273–82.
Van As G. Erbium lasers in Dentistry. Dent Clin North Am 2004; 48: 1017–59.
Eversole LR, Rizoiu IM, Kimmel A. Osseous repair subsequent to surgery with
an erbium hydrokinetic laser system. Presented at the International Laser
Congress. International Proceedings Division; 25–28 September 1996. Athens,
Greece.
Gouw-Soares S, Tangi E, Haypel P, Cardoso W, Edwardo CP. The use of Er: YAG,
Nd: YAG, and Ga-Al-As lasers in periapical surgery: a three-year clinical study.
J Clin Laser Med Surg 2001; 19: 193–8.
Effect of Waterlase Laser
18. Mattison GD, von Fraunshafer JA, Delavanis PD, Anderson AN.
Microleakage of retrograde amalgams. J Endod 1985;
11: 340–5.
Gagliani M, Taschieri S, Molinari R. Ultrasonic root-end ultrasonic root-end
preparation: influence of cutting angle on the apical seal. J Endod 1998; 24:
726–80.
Carr GB. Advanced technique and visual enhancement for endodontic surgery.
Endod Rep 1992; 7: 6–9.
Nedderman TA, Hartwell GR, Partell FR. A comparison of root surfaces
following apical root resection with various burs, scanning electron microscopy
evaluation. Endod J 1998; 14: 423–7.
Glockner K, Rumpler J, Ebeleseder K, Stodler P. Intrapulpal temperature
during preparations with the ER:YAG laser compared to the conventional bur: an
in vitro study. J Clin Med Surg 1998; 16: 153–7.
Wright HM, Loushine RJ, Weller RN, Kimbrough WF, Waller J, Pashley DH.
Identification of resected root-end dental cracks. A comparative study of
transillumination and dyes. J Endod 2004; 30: 712–15.
