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Intraosseous anesthesia using a computer-controlled system during non-surgical periodontal therapy (root planing): Two case reports

Local anesthesia is administered to control pain, but it may induce fear and anxiety. Root planing is a non-surgical periodontal therapy; however, when it is performed in an extensive manner, some tissue removal is inevitable. Notably, this removal may be so painful that local anesthesia is required to be administered to the area scheduled for the treatment. Although patients tend to accept root planing easily, they frequently express a fear of local anesthesia. Intraosseous anesthesia (IA) is an intraosseous injection technique, whereby local anesthetic is injected into the cancellous bone supporting the teeth. A computer-controlled IA system (CIAS) exhibits multiple benefits, such as less painful anesthesia, reduced soft tissue numbness, and the provision of palatal or lingual, as well as buccal, anesthesia via single needle penetration. In this report, we present two cases of root planing that were performed under local anesthesia, using a CIAS.

Local anesthesia is administered to control pain, but it may induce fear and anxiety [1,2]. Root planing is a procedure by which residual, embedded subgingival calculus and cementum are removed from tooth roots, thereby producing smooth, hard, and clean root surfaces [3]. When extensive root planing is performed, some pain associated with tissue removal is inevitable. To control the pain, presurgical local anesthesia is administered.
Conventional local infiltration anesthesia (CLIA) is typically performed, involving multiple needle penetrations that burden both patients and dentists. Additionally, the duration of anesthesia after treatment is long, which requires patients to endure extended soft tissue numbness.
To reduce the pain associated with local anesthesia, many painless anesthetic devices have been developed that are considered alternatives to conventional anesthesia [4][5][6].
The administration of intraosseous anesthesia (IA) involves intraosseous injection, whereby local anesthetic is injected into the cancellous bone supporting the teeth.
One method for administering intraosseous injections, a computer-controlled IA system (CIAS) (Fig. 1), exhibits some advantages, including less painful anesthesia, reduced soft tissue numbness, and the provision of palatal or lingual, as well as buccal, anesthesia with single needle penetration. However, its disadvantages include additional application time, compared with conventional anesthetic techniques, and shortened duration of the anesthetic effect [7]. Thus, it may be ideal in non-surgical  procedures, rather than in surgical therapies with long operating times. We report two cases of root planing under local anesthesia, using a CIAS, followed by literature review.

Case 1
A 60-year-old female patient with moderate chronic periodontitis presented to our department for periodontal therapy ( Fig. 2A). Root planing under IA was planned to reduce the pain during local anesthesia because she  maxillary canine, the second premolar and first molar, and on the distobuccal part of the second molar, to induce infiltration anesthesia (Fig. 3B). No anesthetic agents were injected into the palatal region. Next, an injection needle was inserted for intraosseous injection (Fig. 3C).
A total of 2.7 ml (1.5 cartridge) lidocaine was used in this procedure. The patient reported pain during infiltration (NRS: 5). After the anesthesia, the probing pocket depth was measured using a periodontal probe, and root planing was performed. The patient did not report significant discomfort during the anesthesia or surgical procedures. After surgery, the patient did not exhibit paralysis at the anesthetized areas and returned home without discomfort. Generally, when CLIA is induced, soft tissues of the lips and cheeks, on which the anesthesia is induced, become paralyzed for an extended period, which persists even after surgery completion [12]. However, the patients in this report did not experience soft tissue paralysis beyond the surgically-necessary paralysis of the teeth and gums. Local anesthesia, designed to reduce pain during a dental procedure, can itself cause stress and complicate dental procedures [8]. Root planing is a non-surgical periodontal treatment that is quickly completed and does not cause significant postoperative pain; therefore, patients do not fear this technique. However, they complain of pain during local anesthesia administered before the treatment, thus causing difficulty for both patients and operators [8]. The CIAS causes less pain than does CLIA during infiltration before intraosseous injections, which is largely because the injection speed is maintained at 1 ml/min by a computer-controlled device.
Malamed reported that because anesthetic agents can be injected at a constant rate by an electronic device, electronic injection causes less pain than does conventional, manual methods of injection [2].
The patients experienced almost no pain during treatment, immediately after the induction of anesthesia.
The first patient reported slight pain during the root planing of the distobuccal area of the second molar in the left mandible. The second patient reported mild pain during the root planing of the interdental region of the central incisor, but did not require additional anesthetic injections. Coggins et al. [11] emphasized the periodontal bone structure in successful intraosseous injections, as insufficient induction of anesthesia, rather than an insufficient dose of anesthetic agents, is related to bone density. Therefore, they recommended CLIA, rather than increased doses of anesthetic agents, when insufficient anesthesia is induced (following an intraosseous injection) because of high bone density. The areas of mild pain during the treatment for both patients showed high bone densities on X-rays, which may have caused insufficient anesthesia.
In the presently reported cases, the strengths of the intraosseous injection were less painful anesthesia, reduced soft tissue numbness, and small numbers of needle penetration. Pain was significantly reduced when anesthesia was induced using the CIAS. Moreover, because no unnecessary paralysis of the soft tissues occurred, the patients recovered rapidly after IA, compared with CLIA.
In this study, induction of local anesthesia using the CIAS during a non-surgical periodontal therapy significantly reduced anxiety and pain. More detailed studies involving larger sample sizes are warranted to establish the use of the CIAS in actual clinical settings for various purposes.