Introduction

Surgical endodontic therapy (apicectomy) is a treatment alternative aimed at removing periapical inflammatory tissue followed by apical resection and retro-filling of the root canal.1 Such procedures are performed through a trans-osseous approach.2 The term 'apicectomy' has been well known for more than 200 years and surgical management is intended to eliminate or block infection originating in the root canal. The root end is customarily sealed to prevent pathogenic products remaining in the root canal from reaching the peri-radicular tissue.3,4

Different cases require different treatment modes. It is important to emphasise that endodontic treatment remains the primarily preferred therapeutic action.

The optimal way to address endodontic failures is to re-treat the root canal system first if clinically possible and only then, if no remission is seen, perform surgery with curettage.5,6,7Advances in instruments (endodontic microsurgery), materials and techniques have made endodontic surgery a more predictable procedure.8,9,10

In a review of randomised controlled trials to establish the relative effectiveness of surgical vs. non-surgical endodontic re-treatment, the Cochrane Database System Review11 concluded that there is no apparent difference between either of the treatments, rather that more significant criteria were risk of complications, operator skill, technical feasibility and the extent of the presenting lesion.

It is important to recall the principles of endodontic surgery that dictate treatment. The prime considerations may be summarised as follows:

  • A thorough appreciation of surgical anatomy is of primary importance in order to effect a well-performed procedure and appropriate radiographic investigation must precede any surgical approach in order to properly assess the lesion and associated anatomical structures12

  • Surgical access – the preferred muco-periosteal access is through a semi-lunar incision, which must always be positioned above the lesion and never through the lesion

  • Operator experience and good surgical technique13

  • Thorough removal of associated granulation tissue or more organised peri-apical pathology

  • Appropriate resection of the root apex, to eradicate the apical tip and any accessory root canals in this region. Wherever possible, the resection level should be coincident with the buccal or labial alveolar bone level

  • Retrograde obturation – it is considered appropriate that a retrograde root canal filling should be performed routinely during apical surgery. The purpose of the retrograde filling is to seal the exposed root canal and prevent leakage of pathogens into the peri-apical area. Isolation of the root area is vital during this procedure and will enhance the successful outcome.14

An array of potential retrograde filling materials have been advocated and such choice has been extensively investigated in vivo and in vitro.15,16

Many studies have been performed to compare the success rates of various root-end filling materials, such as SuperEBA™ (Harry J. Bosworth Company), IRM® (Intermediate Restorative Material, Dentsply International), zinc-free high copper amalgam, gold leaf, gutta-percha, calcium hydroxide and silver.17,18,19,20

Using the Er:YAG laser in apicectomy surgery

The erbium yttrium aluminium garnet (Er:YAG) laser has a wavelength of 2,940 nanometres and emits as a free-running pulsed train of photons in the Mid infra-red portion of the electromagnetic spectrum. Successive laser pulses are 100-200 microseconds in width. The prime chromophore of this laser wavelength is water, which makes it appropriate for ablating both hard and soft oral target tissue. Incident laser energy is absorbed by the chromophore, converted into thermal energy which results in expansive vaporisation. Such action causes a dislocation of the tissue structure and ablation; often this is accompanied by an audible 'popping' sound.

The Er:YAG laser can make an incision for flap lifting, such as a crestal incision, an intrasulcular or vertical release incision or semilunar incision. The laser produces a wet incision (some bleeding) as opposed to a dry incision (no bleeding) produced by current CO2 lasers.21,22,23

Vaporisation of granulation tissue24,25 (if any exists) after raising a flap is efficient with the Er:YAG laser, offering a lower risk of overheating the bone26,30,31 than that posed by the current diode or CO2 lasers.

Detoxification of the infected site by lasing directly on the bone – studies have shown that Er:YAG laser energy effects on bone include bacterial reduction.27,28,32

Ablation of alveolar bone tissue with the Er:YAG laser can be used for remodelling, shaping and ablation of necrotic bone.29,30

Root apex resection using the Er:YAG laser in contact mode and preparation of the apex cavity for retrograde.

Case report

This case describes the use of an Er:YAG laser for apicectomy treatment and the advantages of this laser wavelength in performing apicectomy versus conventional methods.

A 28-year-old female presented complaining of pain and swelling of the gingival tissue associated with the upper right central incisor tooth (Fig. 1). This condition had been present for some time, with episodes of associated discharge from the area. On examination, the tooth had been restored at some time with full-veneer porcelain fused to metal crown. The general level of oral health was considered good, with evidence of adequate oral hygiene; the periodontal condition was good with no pocketing or bleeding on probing. The patient's general medical history was uneventful and she was taking no medication. The patient – after being referred to our clinic for laser surgery by her permanent dentist – was informed of the treatment possibilities and chose the laser surgery route.

Figure 1
figure 1

At presentation - radiolucency area at the location of apex #8

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Panoramic and periapical film showed a radiolucent area around the apical portion of the tooth and root canal (Fig. 2). A diagnosis of peri-apical granuloma, suggestive of failure of the orthograde root filling was made and treatment indicated surgical curettage of the area and apicectomy procedure.

Figure 2
figure 2

X-ray at presentation

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Treatment would involve the use of an Er:YAG laser to perform:

  • The flap incision30

  • Expansion of the entrance to the defect

  • Ablation of granulation tissue around the apex

  • Remodelling, shaping and ablating of the bone

  • Resection of the apex

  • Preparing the apex cavity for retrograde (root filling)

  • An associated osteogenic (GBR) procedure to prevent soft tissue in-growth and maintain the form of the alveolus.

Treatment alternatives could consist of traditional scalpel, curettes, and rotary instruments.

Treatment

A dual-wave laser system with operating wavelengths of 2,940 nm and 10,600 nm (OpusDuo™ AquaLite™, Lumenis, Ltd. Yokneam, Israel) was employed for this procedure.

The laser operating parameters employed for the various surgical stages were as shown in Table 1.

Table 1 Laser operating parameters for thedifferent surgical stages
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A semilunar incision was made (after anaesthesia).32,33 The incision extended from a point approximate to the distal area of the upper right lateral incisor to the distal of the upper left central incisor (Figs 3, 4) and a buccal flap was lifted (Fig. 5). Care was taken to minimise soft tissue trauma. A small fenestration of the labial bone was discovered and surrounding bone was ablated in order to expand the entrance to the defect (Fig. 6). A large quantity of granulation tissue was removed with a curette (Fig. 7) and the granulation tissue left behind was ablated with the Er:YAG laser (Fig. 8).

Figure 3
figure 3

Semilunar incision with the Er:YAG laser, 200-micron sapphire tip in contact mode

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Figure 4
figure 4

Semilunar incision

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Figure 5
figure 5

Raising the flap

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Figure 6
figure 6

Expanding the entrance to the lesion with the Er:YAG laser, 1,300-micron sapphire tip in non-contact mode (700mJ/12 Hz, 8.4W)

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Figure 7
figure 7

Granulation tissue

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Figure 8
figure 8

Ablating soft tissue with the Er:YAG laser

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Following surgical exposure, the root apex was sectioned (Fig. 9); the Er:YAG laser energy produced a smooth, clean resection without visible signs of thermal damage, which was in accordance with reported findings.34 At the same power setting the cavity of the apex was prepared for retrograde obturation (Fig. 10). Finally the bone defect was shaped and remodelled.

Figure 9
figure 9

Using the Er:YAG laser to cut the apex and to prepare the apex cavity for retrograde filling (800-micron tip in contact mode)

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Figure 10
figure 10

The apex cavity is prepared for retrograde filling

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The retrograde cavity was sealed with IRM® (Fig. 11). IRM has been recommended for root-end filling during endodontic therapy and presents advantages such as ease of placement, decreased setting time, toxicity, and solubility.34 Due to the fact that biocompatibility is in today's forefront, time-tested materials such as silver and amalgam are clearly being used less.28 The success rate of IRM stands at 91%.29

Figure 11
figure 11

The retrograde filling with IRM®

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The defect was filled with BioOss® (Geistlich Pharma AG, Wolhusen, Switzerland, Fig. 12). The purpose of GBR is to provide a matrix for new bone formation and prevent soft tissue migration into the surgical defect. The flap was sutured with 3-0 silk with careful attention being paid to good primary closure (Fig. 13). After suturing, the CO2 laser was used at a power setting of 4W in continuous wave mode and a focused beam to ablate excess soft tissue (Figs 14, 15, 16).

Figure 12
figure 12

The bone defect is filled with BioOss® for GBR procedure

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Figure 13
figure 13

Primary closure

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Figure 14
figure 14

Ablating soft tissue with the CO2 laser

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Figure 15
figure 15

Final result - immediately post-op

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Figure 16
figure 16

X-ray immediately post-op

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The patient was prescribed antibiotics to avoid infection. She was also given Motrin (800 mg x 15 tablets) for pain. She was instructed to rinse with chlorhexidine 0.2% the next day and for two more weeks, three times a day and was advised to maintain good oral hygiene.

At ten days post-op the patient returned for inspection and sutures removal (Fig. 17). The swelling had resolved, there were no signs of fistula and healing was progressing well. The patient came in for a scheduled three-week follow-up; the healing progression was satisfactory with fistula or scar tissue (Figs 18-19). After six weeks the soft tissue was completely healed without complications. The soft tissue was healing over the bone and there were no bony projections observed under the soft tissue (Figs 20, 21). The prognosis was considered excellent.

Figure 17
figure 17

Ten days post-op

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Figure 18
figure 18

Three weeks post-op

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Figure 20
figure 19

X-Ray; six weeks post-op: no radiolucency area

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Figure 21
figure 20

Six weeks post-op: no scar tissue

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Discussion

The rate of success with the apicectomy procedure is over 91%.36 Apicectomy failure is generally related to inappropriate marginal sealing of the retro-cavity, which allows percolation of micro-organisms and their products from the root canal system into the peri-apical tissue.37

The majority of periapical lesions harbour a variety of flora which cannot be eradicated despite a thorough apicectomy procedure.38 Surgical re-treatment of teeth previously treated with surgery is a valid alternative to extraction.39

Apicectomy and retro-seal procedures should continue to be a mainstay of dental treatment because not all root canal therapy is successful.40 As practitioners have increased their knowledge and skills in the art of saving teeth, peri-radicular surgery has increased in importance.41 With bright illumination and magnification under the operating microscope and the added benefit of many micro instruments, endodontic surgery has evolved into microsurgery.8,9

The use of the erbium YAG 2,940 nm laser has been demonstrated to be effective in the surgical ablation of tooth tissue and bone. Advantages of this modality over conventional rotary instrumentation may include precision, bacterial decontamination, less collateral damage and tactile stimulation. In addition, although studies have been equivocal, the use of this laser in surgical procedures may result in less operator fatigue and greater patient acceptance. What has been demonstrated is the enhanced early healing response in bone tissue and a lesser level of post-operative complications. Although studies into the use of the Er:YAG laser in clinical bone surgery procedures have reported inconclusive subjective advantages in terms of time required, post-operative pain levels or ease of access, histological investigations have demonstrated better levels of early healing of the bone when the laser is compared to the surgical bur, piezo-saw or carbon dioxide lasers.42,43

Conclusion

The outcome of this clinical case indicates that the use of the Er:YAG laser should be considered an alternative, suitable and useful method for performing apicectomy and has been shown to be effective and safe.44,45,46

A case of surgical resection of a root apex associated with peri-apical pathology, using the Er:YAG laser has been demonstrated, with evidence of good post-operative healing.47,48

Figure 19
figure 21

X-ray three weeks post-op

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