The carbon dioxide laser in soft tissue preprosthetic surgery

The carbon

dioxide

M. A. Pogrel, University

San Francisco,

carbon

bleeding,

pain,

patients

requiring

dioxide

swelling, soft

performed

on an ambulatory and pain,

evaluation.(J

contraction.

as measured for scalpel soft tissue

and sulcus no bleeding

on a linear

no analgesics.

for

with

to vaporize

surgery,

removal,

basis

San Francisco,

The laser

preprosthetic

quoted

advantages

has the ability

hyperplasia

required

is historically have

laser

tissue

reduction,

the patients

School of Dentistry,

or wound

tuberosity minimal

surgery

M.B., Ch.B., B.D.S.*

of California,

The surgical

laser in soft tissue preprosthetic

pain

Wound wounds.

scale,

contraction The carbon

preprosthetic

surgery

soft

was

or infection.

Surgery

was

Swelling

was

moderate.

did occur dioxide

with

little

on 27

frenectomies,

deepening.

that

tissues

evaluated

including

was

Calif.

laser warrant

One third

but was would

of

less than appear

to

further

PROSTHETDENT 1989;61:203-8.)

L

aser is an acronym for light amplification by the stimulated emission of radiation. To produce laser energy, there are a number of substances that can be stimulated to produce energy that is coherent and monochromatic (the same color and wave length) and capable of being collimated (produces parallel beams). Each substance stimulated will produce electromagnetic energy of a different wave length. When carbon dioxide gas is stimulated, it produces energy with a wave length of 10.6 pm, which places it in the infrared portion of the spectum, which is invisible to the human eye. This wave length is, however, well absorbed by water that is vaporized by a carbon dioxide laser beam. Because human soft tissues are largely composed of water, the carbon dioxide laser has proved to be an effective tool for vaporizing them.’ Bone and teeth, however, contain considerably less water and are less effectively vaporized by a carbon dioxide laser, which make it an unsatisfactory means of removing these tissues.2 The depth of a laser incision depends on the length of time the beam is focused on the spot. There is no tactile sensation. Laser surgery has been compared in different studies with scalpel surgery,3 cryosurgery,4 and electrosurgery. In each study, distinct advantages have been claimed for the laser. They are that (1) laser surgery is precise and self-sterilizing because the tissues are vaporized, (2) it is relatively bloodless, because any blood vessel with a diameter less than the width of the laser beam will be vaporized and heat sealed,’ (3) it is relatively pain-free because nerves that are transected are also heat sealed by the laser beam,6 (4) postoperative edema and swelling appear to be minimal presumably because lymphatics are also sealed, and (5) laser wounds contract less than other types of wounds, possibly because

*Assistant gery.

THE

JOURNAL

Professor,

Department

OF PROSTHETIC

of Oral and Maxillofacial

DENTISTRY

Sur-

Fig. 1. Xanar Articulator surgical carbon dioxide laser with handpiece for intraoral use.

fewer myofibroblasts are seen in the wounds and these cells are believed to be the etiologic agents in wound contraction.7 Some clinical disadvantages of the carbon dioxide laser over other treatment modalities are that (1) studies have shown that in the early stages, laser wounds have less tensile strength than scalpel wounds, although after 3 weeks the 203

POGREL

Fig. 2. A, Patient with mandibular labial frenum. B, Mandibular labial frenenctomy performed with laser. Note good sulcusdepth.

strengths are similar,sand (2) although the laserbeamis focused, it can potentially injure tissuesthat might be inadvertantly contacted by the laser beam if the arm is bumped or slips; therefore, a number of safety measuresare mandatory during laser surgery. All personnel in the room must wear eye protection. Any tissuesthat may be contacted by the laserbeamif it slipsshouldbe protected by wet gauzeor towels. If the laserbeamhits a wet towel, it merely vaporizes someof the water. Teeth canbe protected by a dull periosteal elevator or matrix band. Bright metallic objects should not be used becausethey can reflect the laser beam. At this time the least expensive carbon dioxide lasersuitable for oral surgery costs approximately $17,000. The carbon dioxide surgicallaser hasbeen widely usedin different specialties,“12 including some intraoral applications,13-I6 but it does not appear to have been described for soft tissue preprosthetic surgery. Because many of the claimed advantagesof the carbon dioxide sur-

204

gical laser appear to be ideally suited for the problems of preprosthetic surgery, a study wasdone usingthis modality.

MATERIAL

AND

METHOD

The Xanar Articulator (Coherent Medical Group, Palo Alto, Calif.) surgical carbon dioxide laser equipped with a handpiecefor intraoral use (Fig. 1) wasevaluated clinically on patients requiring the following procedures. 1. Frenectomies, including maxillary labial frenectomies were performed. 2. Reduction of enlargedsoft tissuemaxillary tuberosities wasperformed. 3. Removal of denture hyperplasia of the maxillae and the mandible was performed. 4. A trial using the laser for vestibuloplasty was carried out in the creation of a supraperiosteallower labial vestibular extension anterior to the mental foramina. No graft was

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CARBON

DIOXIDE

LASER

IN PREPROSTHETIC

SURGERY

Fig. 3. A, Soft tissue maxillary tuberosity. B, Tissue removed, C, Satisfactory epithelialization 3 weeksafter operation.

applied, but the patient’s lower denture wasmodified by the addition of Coe Soft (Coe Laboratories, Inc., Chicago, Ill.) material so that the labial flange extended into the newly created defect to act as a stent. The size of the extension created and the subsequentcontraction wasmeasuredfrom the visible wound edgeto the depth of the sulcuson both the labial and mandibular surfaceswith calipers. The wound edge was tattooed at one point to aid measurement as described by Hillerup.” The energy produced by the laser beam is expressedas power density in watts per squarecentimeter (W/cm’). This is a function of the power setting in watts and the area of the focusedbeam as it contacts the tissues.For the patients in this study, surgery wasperformed with a power of 10 watts and a 1 mm spot-size beam, giving a power density of 1270 W/cm2. All of the wounds were evaluated for bleeding, swelling, speedof healing, contraction, and relapse. Pain was evaluated on a 10 cm visual analoguescalewhere 0 signified no pain and 10 signified the worse pain imaginable. This type of scalehas been evaluated.17All surgerieswere performed asoffice procedureswith the patients under local anesthesia, often supplementedwith intravenous sedation, and all surgerieswere carried out by the sameoperator (MAP). Patients were referred for laser surgery by a number of

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prosthodontists and general dental practitioners. For this reasonit wasnot possibleto formulate an objective evaluation of the final prosthodontic result, but subjective results were obtained.

RESULTS Frenectomies Eight frenectomies were carried out with the patient under local anesthesia;each operation took approximately 20 seconds.No suturing or packing of any kind wasusedafter the procedure. A typical result is shownin Fig. 2. There was no bleedingor discernibleswellingin any patient and all the lesionswere fully reepithelialized within 12 days. On the linear pain scale, the mean value was 2.25 (range 1 to 4), which signifiesmild pain. Of the eight patients, only two took an analgesicof any kind, which was acetaminophen. On final evaluation at 12 weeks after surgery, six of the eight frenectomieswerejudged to have satisfactory results, but for two patients (one lingual frenectomy, one lower labial frenectomy) there wasconsiderablecontraction, and although the final result wassatisfactory, a better result could probably have been obtained with a more conventional frenectomy technique. However, in all eight patients, the referring dentist stated that the result was satisfactory for prosthodontic requirements.

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Fig. 4. A, Severe mandibular hyperplasia. B, Tissue removed. C, Three weeks after operation good epithelialization with lack of scarring is shown.

Tuberosity

reductions

Soft tissue tuberosity reduction was done on four patients. The excess tissue was satisfactorily vaporized down to periosteum with the laser. The exposed regions were left to epithelialize secondarily. A typical result is shown in Fig. 3. The average treatment time in these patients was 6 minutes and in no instance was there bleeding, swelling, or recurrence of the excess tissue. Two patients wore upper dentures relined with Coe Soft material immediately after the procedure. On the linear pain scale, a mean value of 5 was recorded (range 3 to 9), which signifies that moderate pain was caused by the procedures. These pain scores are difficult to interpret because the one patient who recorded a score of 9, indicating that it was extremely painful, stated that she had not, however, taken any analgesic whatsoever following the procedure. All of the other patients had taken a moderatestrength analgesic such as acetaminophen with codeine. On one patient a laser tuberosity reduction was carried out on one side and a more conventional scalpel excision reduction was carried out on the other side. The patient stated that the laser side felt more comfortable and did in fact heal first. In addition, the laser reduction was quicker to perform. Since a larger area of epithelium is removed in these procedures, reepithelialization took longer, up to 4 weeks for

206

complete reepithelialization, although patients stated that the area was completely painless after the first 6 days.

Denture

hyperplasia

Laser removal of denture hyperplasia was done in 11 patients; in each patient the hyperplasia was vaporized with the laser and the resulting tissues were left exposed to reepithelialize. No form of grafting or suturing was done and patients were encouraged to wear their dentures again as soon as possible after any required revision of the denture flange and relining with Coe Soft material. A typical patient is shown in Fig. 4. Reepithelialization occurred in all patients within 14 days and in no instance was there bleeding swelling, or mental nerve damage. Pain scores of between 3 and 6 were recorded with a mean value of 3.8, indicating mild-to-moderate pain. Contraction where it could be measured, was approximately 20% after 6 weeks, at which time new denture construction was commenced.

Sulcus

deepening

A buccal vestibular extension for sulcus deepening in the anterior mandible was created in four patients by using the laser. The time required for this procedure was approximately 5 minutes, and after the procedure the patients wore

CARBON

DIOXIDE

LASER

IN PREPROSTHETIC

SURGERY

their old lower dentures with an extension to the anterior labial flange made with Coe Soft material to occupy the newly created extension. In no instance was there bleeding or swelling, and reepithelialization occurred over a 3-week period. A mean pain score of 4 was recorded (range 3 to 5), indicating the procedure to be moderately uncomfortable. In no patient was mental nerve function affected. There was a mean wound contraction of 40% present after 6 weeks (range 30 % to 45 % ) but even so a satisfactory final result was obtained in that, for each patient, a satisfactory new lower denture could be constructed. In each instance, the referring dentist believed the procedure had aided denture construction and the patients considered the fit and function of their new dentures superior to their former dentures. In all of the 27 patients treated, no antibiotics were prescribed and no postoperative infections resulted. Nine of the 27 patients did not take any analgesic and an additional five used nonprescription analgesics only, whereas 13 patients needed a medium-strength prescription analgesic.

DISCUSSION The surgical carbon dioxide laser appears to have a number of potential advantages in soft tissue preprosthetic surgery that merit further exploration. It enables a number of procedures to be performed in the dental office quickly and with low morbidity. For frenectomies, the main advantages appear to be speed and a clean, bloodless field. However, a contraction and recurrence of the frenum occurred in 25% of patients. For palatal hyperplasia and soft tissue tuberosity reduction, the laser appears to be faster and cleaner with less discomfort -than is normally associated with this form of surgery by other techniques, and it may be the treatment of choice for these procedures. Denture hyperplasia removal remains a controversial problem. If the hyperplasia is removed and the edges of the enithelium are reannroximated with sutures, there is often -considerable loss of sulcus depth. Secondary epithelialization techniques are usually uncomfortable and result in considerable wound contraction so that in many patients, skin or mucosal grafting must be used. Although a satisfactory result is obtained, there is a higher morbidity rate. In these circumstances, the properties of the laser for relatively painless surgery and recovery with less wound contraction appear to offer great advantages, as demonstrated clinically in the 11 patients described. Thus, the laser may be the treatment of choice for removal of regions of denture hyper. . plasia. For buccal extension vestibuloplasty, many of the same problems arise as with hyperplasia removal in that discomfort and wound contraction usually necessitate some form of grafting procedure. Nevertheless, it has been shown that with the laser, an extension can be created with only mildto-moderate discomfort, which is controlled with mediumstrength analgesics. However, wound contraction occurs in

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approximately 40% of treated patients which, although considerable, is less than is normally obtained with mandibular secondary epithelialization techniques.l’ If this wound contraction is taken into account, it probably represents a satisfactory way of achieving a gain in sulcus depth as a lowmorbidity ofice procedure. Skin grafts do not appear to take on lasered epithelium, probably because of the lack of exudate to nourish the graft in the early stages and difficulty in obtaining a new blood supply in the latter stages.7 Pain is difficult to evaluate, but, on the data obtained in this study, it seems likely that discomfort is less after laser surgery than by more conventional techniques and it is definitely less than the discomfort after conventional surgery with a secondary epithelialization technique. Swelling and edema were virtually nonexistent after laser surgery.

SUMMARY The surgical carbon dioxide laser has a number of claimed advantages over other modalities for soft tissue surgery. Many of these advantages appear to be particularly applicable for soft tissue preprosthetic surgery. In this study, the laser appeared particularly suitable for frenectomies, removal of hyperplastic tissue, and some sulcus deepening procedures. REFERENCES 1. Hall RP, Hill DW, Beach WD. Carbon dioxide surgical laser. Ann R Co11 Sure-- Enel 1971:48:181-8. 2. Small IA, Osborn TP, Fuller T, Hussain M, Koberneck S. Observations of carbon dioxide laser and bone osteotomy of the rabbit tibia. J Oral Surg 1979:37:159-66. 3. Fisher SE, Frame JW, Browne RM, Tranter RMD. A comnarative histological study of wound healing following CO, laser and conventional surgical excision of canine buccal mucosa. Arch Oral Biol 1983;28:287-91. 4. Wetchler SJ. Treatment of cervical intraepithelial neoplasia with the CO, laser: laser versus cryotherapy. A review of effectiveness and cost. Obstet Gynecol Surv 1984;39:469-73. 5. Bellina JH, Hemmings R, Voros JI, Ross LF. Carbon dioxide laser and electrosurgical wound study with an animal model: a comparison of tissue damage and healing patterns in peritoneal tissue. Am J Obstet Gvneco1 i984,148:327-34. -6. Tuffen JR, Carruth JAS. The surgical carbon dioxide laser. Br Dent J 1980:149:255-8. 7. Fisher SE, Frame JW. The effects of the carbon dioxide laser on oral tissues. Br J Maxillofac Surg 1984;22:414-25. 8. Buell BR, Schuller DE. Comparison of tensile strength in Co, laser and scalpel skin incisions. Arch Otolaryngol 1983;109:465-7. 9. Healy GB, Strong MS, Shapshay S, Vaughan C, Jako G. Complications of CO, laser surgery of the aerodigestive tract: experience of 4416 cases. Otolaryngol Head Neck Surg 1984;92:13-8. 10. Leuchter RS, Townsend DE, Hacker NF, Preterius RG, Lagasse LD, Wade ME. Treatment of vulvar carcinoma in situ with the CO, laser. Gynecol Oncol 1984;19:314-22. 11. Sacchini V, Love GF, Arioli N. Nava M, Bandierarnonte G. Carbon dioxide laser in scalp surgery. Lasers Surg Med 1984;4:261-9. 12. Apfelberg DB, Maser MR, Lash H. Review of usage of argon and carbon dioxide lasers for pediatric hemangiomas. Ann Plast Surg 1984;12:353-60. 13. Pecaro BC, Garehime WJ. The CO, laser in oral and maxillofacial surgery. J Oral Maxillofac Surg 1983;41:725-8. 14. Apfelberg DB, Maser MR, Lash H, White DN. Benefite of the CO, laser in oral hemangioma excision. Plast Reconstr Surg 1985;75:46-50. 15. Pick RM, Pecaro BC, Silberman CJ. The laser gingivectomy. The use of the CO, laser for the removal of phenytoin hyperplasia. J Periodontol 1985;56:492-6.

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16. Hillerup S. Tattoo marking for registration of relapse after oral vestibuloplasty. Int J Oral Surg 1975;4:65-8. 17. Ohnhaus EE, Adler R. Methodological problems in the measurement of pain: a comparison between the verbal rating scale and the visual analogue scale. Pain 1975;1:379-84. 18. Hillerup S. Healing reactions of relapse in secondary epithelialization vestibuloplasty on dog mandibles. Int J Oral Surg 1980;9:116-27.

Cross-sectional partial denture Bo Bergman, University

of Umei,

requests

of Odontology,

and Gunnel Umel,

Ericson,

to:

DR. M. A. POCREL UNIVEKSITY OF CALIFORNIA, SCHOOL OF DENTISTRY SAN FRANCISCO, CA 94143

study of the periodontal patients

D.D.S., Odont.Dr.,* Faculty

Reprint

SAN FRANCISCO

status

of removable

D.D.S.**

Sweden

Thirty-four patients, 18 men and 16 women with a mean age of 62 years, provided with removable partial dentures were reexamined after 3 years. Approximately 92% of the dentures were bilateral distal-extension prostheses. The periodontal parameters registered were (1) oral hygiene, (2) gingival inflammation, (3) pocket depth, and (4) tooth mobility. Fourteen of the patients had followed the recommendation to visit a dentist for regular checkups at least once a year. For all periodontal parameters, the results were somewhat better for those patients who had regular checkups than for those who had not. The results for the regularly checked patients were similar to those of the patients in an earlier longitudinal study from the same clinic after a corresponding period of time. Thus the good results obtained in the longitudinal study were duplicated 10 years later in this cross-sectional study. (J PROSTHET DENT 1989;61:208-11.)

S

Forty-three patients were treated with removable partial dentures by students in the Prosthetic Department of the University of Ume&during the spring term of 1979.The pa-

tients were recalled 3 years later in 1982. Thirty-four patients responded(79.1%). Of those who did not, four had died, four had moved from the Umea district, and one had been ill for a long time and was unable to attend. The removable partial dentures were constructed according to conventional principles described by Zarb et al.‘j Careful pretreatment had preceded the prosthetic treatment, including instruction in and control of oral hygieneprocedures. Of an initial total of 208 teeth, five with doubtful periodontal prognosisfrom the beginning had been extracted during the 3-year period. Some comparative data on patients and prosthesesin this study (1979)and the 1969study are shown in Table I. Periodontal parameters that were recorded by using the samecriteria asin the 1969study’ were (1) oral hygiene* according to the plaque index (PlI) system,7 (2) gingival inflammation according to the gingival index (GI) system,’ (3) pocket depth measuredto the nearest,millimeter with a graduated probe at six locations around each tooth (mesialbuccal, buccal, distal-buccal, distal-lingual, lingual, and mesial-lingual), and (4) tooth mobility recorded according to the scaleof:

This study was supported by grants from the Swedish Patent Revenue Research Fund and the University of Umei. *Professor and Chairman, Department of Prosthetic Dentistry. **Assistant Professor, Department of Prosthetic Dentistry.

*In a previous publication based on the same patient material,5 the degrees 1,2, and 3 were pooled together to enable the level of oral hygiene in that study to be classified as plaque present or not present.

everal clinical studieshave recorded reactionsin the periodontal tissues of patients with removable partial dentures.’ One of the authors made a longitudinal study of removable partial denture patients starting at the end of 1968and beginning of 1969and covering 10 years.‘-* In contrast to the results of other studies,no significant deterioration of the periodontal tissueswasobservedin this study (to be referred to asthe 1969study). Aware that thesefavorable results may be the result of a high degree of motivation amongthe patients, it was thought to be valuable to collect data for the sameperiodontal parametersin a cross-sectional study. The aim of this study wasto examine a patient population previously treated with removable partial dentures with special reference to their periodontal status and compare the results with those of the 1969study. Data concerning the cariessituation in the present cross-sectionalpatient study have been published.5

MATERIAL

208

AND

METHODS

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