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Keywords:

  • Er,Cr:YSGG laser;
  • implant;
  • explantation;
  • removal;
  • minimally invasive

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case description and results
  5. Discussion
  6. References

Explantation of failed dental implants has traditionally been performed by mechanical bone removal techniques. The advent of intraoral laser surgery has seen increasing numbers of applications in oral implantology. The technique demonstrates safe and efficient explantation of a failed dental implant using Er,Cr:YSGG laser. Laser assisted explantation of dental implants is a minimally invasive technique providing an alternative to conventional mechanical explantation techniques.


Abbreviation:
BON

bisphosphonate related osteonecrosis

Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case description and results
  5. Discussion
  6. References

Increasing utilization of dental implants for restoration of deficient dental arches has resulted in a corresponding need for intervention for failing implants.1 Failure of dental implants sometimes requires removal of the implant surgically, of which techniques including block resection, buccal bone ostectomy and trephine osteotomy have been described.2,3 This case report demonstrates the use of Erbium,Chromium: Yttrium,Scandium,Gallium,Garnett (Er,Cr:YSGG) laser (Waterlase MD, Biolase Technologies; Irvine, USA) to facilitate minimally invasive explantation of a failing implant. An Er,Cr:YSGG crystal generates photons through a fibre delivery system that terminates in a sapphire crystal optical tip which is immersed in an air-water spray. The laser produces photons with a wavelength of 2.78 μm pulsed with a variable repetition rate and duration. The mechanism of cutting is through the laser energy being absorbed by the air-water spray which produces microexplosions on the target tissue. This is known as the hydrokinetic effect and produces clean cuts without thermal damage. Previously, the safety and efficacy of the Er,Cr:YSGG laser in surgery has been demonstrated in soft and hard tissue and solidified egg albumin, demonstrating a linear relationship between the mass of tissue removed and the increasing energy output of the laser.4,5

Case description and results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case description and results
  5. Discussion
  6. References

A 63-year-old female presented to a private dental practice with a longstanding history of loose implant supported crowns associated with implants placed in the 14 and 16 sites. The patient has a past history of osteopenia, well-controlled type two diabetes mellitus, as demonstrated by serial HBA1c measurement, and trigeminal neuralgia. Her regular medications include metformin and amitriptyline. The two Bränemark Mk III implants (Nobel Biocare; Gothenburg, Sweden) were placed eight years prior to presentation with simultaneous Caldwell-Luc sinus lift, and the postoperative clinical findings and radiography supported adequate osseointergration. The patient reported that the crowns placed had never been functionally stable, despite multiple attempts at tightening the screws and refabrication of the crowns. The radiographic record over this time demonstrates radiolucencies at the implant-abutment interface on both implants, suggesting that the abutments had not been properly seated on the external hex (Fig 1).

image

Figure 1.  Serial orthopantomogram images of the implants in site 14 and 16 taken January 2006 (a) and December 2008 (b) both prior to presentation. Radiolucency at the implant-abutment interface is visible demonstrating the incorrect seating of the abutments and crowns (arrows). Progressive peri-implant bone loss is also visible associated with the posterior aspect implant in the 16 site.

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The crowns were removed to facilitate further clinical assessment. The implant at the 16 site demonstrated macroscopic damage to the implant-abutment interface and peri-implant pocketing 5–8 mm deep on the lateral and posterior surfaces of the implant, the clinical signs of inflammation were consistent with peri-implantitis (Fig 2).6 Due to the poor prognosis, the patient elected to have the implant removed.

image

Figure 2.  (a) Demonstrates deep probing defects on the lateral aspect of the implant in the 16 site. (b) An occlusal view of the implant 16 showing macroscopic damage to the implant hex.

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The procedure was performed under local anaesthesia, utilizing 1.1 ml Lignocaine 2% 1:80 000 adrenalin. A trial reversal of the implant was attempted without success. The implant was determined to have a length of 10 mm based on documentation and radiographic evidence. Tissue incision using the Er,Cr:YSGG, 2.78 μm wavelength laser was carried out utilizing a 14 mm long, 400 μm diameter optical tip (Fig 3). The optical tip is carried in a contra-angle handpiece, with the tip being bathed in an adjustable air-water spray during ablation. Initially, laser settings of 1.25 Watts at a repetition rate of 30 Hz, S mode, water 8% and air 11% were used to incise soft tissue and granulation tissue circumferentially about the implant. This was followed by bony incision carried out with the laser set at 4.0 Watts, repetition rate 20 Hz, H mode, water 20%, air 20%. After achieving the desired working depth of 10 mm, the implant became mobile and was easily delivered using curved artery forceps. The post-ablation surgical site is demonstrated in Fig 4. The patient was given routine postoperative instructions as per a simple tooth extraction and no postoperative antibiotics were prescribed. The duration of the procedure was approximately 10 minutes.

image

Figure 3.  The 14 mm optical laser tip inserted adjacent to the implant.

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image

Figure 4.  (a) The surgical site after irradiation with the Er,Cr:YSGG laser to the correct working length of 10 mm. (b) The postoperative appearance of the surgical site after implant removal.

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Postoperatively, the patient was reviewed at 2 days, 1 week and 6 weeks. The patient reported no pain and required no analgesia after the procedure. Clinical follow-up demonstrated excellent soft tissue healing in the area. The implant in the 14 site was found to be undamaged with healthy periodontal tissues, and subsequently received a new crown.

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case description and results
  5. Discussion
  6. References

The use of surgical lasers in dentistry has been a rapidly expanding field with well established applications in both soft and hard tissue surgery.7 Explantation is a procedure to remove failing dental implants, often this occurs as the end-point of unsuccessful long-term treatment. With respect to this, it is important to carry out the procedure in an efficient manner with minimal trauma to the patient and minimal risk of postoperative complication, including excessive removal of bone and soft tissue, so as not to exclude future implant therapy.

The Er,Cr:YSGG laser has been demonstrated to effectively cut bone without burning, melting or altering the calcium:phosphorus ratio of the irradiated bone.8 Histological studies indicate that the surrounding area of thermal injury to the adjacent tissues is in the order of 30 μm for soft tissue and 80 μm for bone, utilizing a 2.78 μm wavelength laser, set at 2.0 Watts and a repetition rate of 20 Hz, air 50% and water 50%, delivered via a 400 μm optical tip.9 Comparatively, bone trephines have a larger cutting surface with the difference between the internal and external diameter of the trephines being between 750 to 800 μm (Easyretrieve, Ace Surgical Supply, Brockton, USA). Comparative histological studies have demonstrated a reduced zone of tissue disruption for the Er,Cr:YSGG laser when compared with Nd:YAG, Er:YAG and CO2 lasers, with these lasers producing structural changes in the surrounding tissue to a distance of 800 to 1200 μm.10 Utilizing the Er,Cr:YSGG laser for this minimally invasive technique is advantageous as it preserves tissue in cases where future implant treatment may be desired. However, whether the tissue preserved is of any benefit to the patient in terms of reduced morbidity and reduced need for future osseous augmentation is not clear. In this clinical case the surgical site underwent rapid healing in the two weeks following explantation. Healing of irradiated tissue has previously been described, with more rapid healing of soft tissue, followed by slower healing of bone due to the bone being more susceptible to thermal damage.9,11

Microbial decontamination of peri-implant tissue has been demonstrated using laser techniques.10,12 Decontamination occurs mainly due to the laser wavelength having a high affinity to water, causing a hydrokinetic effect. In this process, the water molecules become energized and propelled by laser energy. As microbes predominantly have water as their intracellular component, energizing the intracellular component causes disruption of the cell membrane, leading to cell death.12 The effect that the laser has on Lipopolysaccharide and other proinflammatory mediators is less clear. It is likely that the decontamination effect also occurs in the surrounding tissues during explantation and may promote uncomplicated tissue healing. As with the reduced removal of tissue, the benefit of microbial decontamination in the peri-implant tissues during explantation has yet to be quantified and requires further research.

Haemostatic control throughout the procedure was excellent, facilitating good visualization and expediting the procedure. The method described was technically easy to perform. However, the operator should avoid excessive hand pressure on the optical tip as it may be prone to fracture. The optical tip provided good access to the site via a contra-angle handpiece and it was easy to determine the working length accurately.

This report describes the authors first attempt at laser explantation. However, a similar technique had been used to extract teeth. During tooth extraction, one incidence of optical tip fracture occurred which did not result in any adverse outcome for the patient. Minimal set up and preparation for the procedure was required with the only special precaution for the laser being appropriate eye protection.

No absolute contraindications to the use of Er,Cr:YSGG laser has been described in the literature. In case selection for laser assisted explantation, relative contraindications to surgical tooth extraction should be applied, especially patients that have a propensity for poor wound healing, are immunocompromised or those that have had previous jaw radiotherapy. As with conventional explantation techniques, the operator needs to take into account adjacent surgical anatomy, including the maxillary sinus and the inferior alveolar nerve. In this case report, we ensured that there was adequate bone superior to the implant to avoid creation of an oroantral communication during the procedure. The use of laser surgery in patients at risk of bisphosphonate related osteonecrosis (BON) of the jaws is not currently recommended. However, there is some emerging evidence for the use of Er, YAG pulsed laser in the treatment of established BON lesions.13

Although no specific complications occurred in this case, the patient should be warned of the expected sequelae to oral surgery, including pain, swelling, and the risk of postoperative bleeding and infection. One report describes a case of subcutaneous emphysema as a complication of oral surgery performed with a CO2 laser. However, this was an extremely rare occurrence.14

The technique describes an effective application of the Er,Cr:YSGG laser in oral implantology. Although other techniques are available, this one delivered the implant quickly, with minimal trauma to the patient and a high level of patient satisfaction. With increasing numbers of implants in use, invariably dentists will encounter situations where implant removal is indicated. This procedure provides an effective option to conventional removal techniques.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Case description and results
  5. Discussion
  6. References