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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 15  |  Issue : 1  |  Page : 39-43

Blood flow oxygen saturation of the dental pulp for prediction of revascularization after maxillary osteotomies


Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta, Egypt

Date of Submission27-Dec-2017
Date of Acceptance10-Feb-2018
Date of Web Publication4-Apr-2018

Correspondence Address:
Mohammad A Elshall
Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University, Tanta
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/tdj.tdj_59_17

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  Abstract 

Introduction
Pulse oximetry is a noninvasive method used in clinical medicine to record blood oxygen saturation levels during the administration of intravenous anesthetic agents, and it has recently been used to assess dental pulp vitality with the same objective.
Objective
Recording the approximate timing of revascularization of maxillary osteotomies and its impact on the healing process through measuring the dental blood flow oxygen saturation level using pulse oximetry.
Patients and methods
This research was carried out on eight patients collected from the outpatient clinic of Oral and Maxillofacial Surgery Department. All patients were complaining of dentofacial deformities; the maxilla was included in their surgical correction either using Le Fort I osteotomy or anterior maxillary osteotomy. In all patients, the pulpal blood flow of maxillary centrals and canines was evaluated using NellcorOximax sensor (pulse oximeter) and were compared with the reading of the index finger. The collected data were recorded and statistically analyzed.
Results
The mean values of the oxygen saturation levels started to be increased gradually from the third week till reaching the normal values at the sixth week without significant differences between dental pulps and the index fingers.
Conclusion
Pulse oximeter is a valuable, simple, noninvasive, and inexpensive tool that could be used clinically to accurately measure the oxygen saturation level of the dental pulp, and thus provides a great help in clinical evaluation of the revascularization process across the osteotomized bony segments. Accordingly, we recommend its routine use in similar situations.

Keywords: blood flow oxygen saturation, maxillary osteotomies, revascularization


How to cite this article:
Elshall MA, Essa EF. Blood flow oxygen saturation of the dental pulp for prediction of revascularization after maxillary osteotomies. Tanta Dent J 2018;15:39-43

How to cite this URL:
Elshall MA, Essa EF. Blood flow oxygen saturation of the dental pulp for prediction of revascularization after maxillary osteotomies. Tanta Dent J [serial online] 2018 [cited 2018 Jun 21];15:39-43. Available from: http://www.tmj.eg.net/text.asp?2018/15/1/39/229250


  Introduction Top


Maxillary osteotomies have been a predictable method for the management of various maxillary deformities for more than 30 years [1]. The correction of upper jaw deformities started with Le Fort I level maxillary osteotomies by Loewe in 1905 [2].

The Le Fort I osteotomy is utilized for the management of many varieties of skeletal malocclusion involving single or double-jaw surgery, whether as a one-piece or multiple-segmented maxilla [3],[4]. Also segmental maxillary osteotomy provides a mean of selective surgical-orthodontic correction of a dentoalveolar malocclusion. Correction is achieved if only that part of the dental arch is actually deformed [5]. Anterior maxillary osteotomy is frequently applied to cases complaining of maxillary excess [6].

Maxillary osteotomies have not been without significant complications for many patients whom undergone these procedures. Many earlier reports in the literature have described these complications, which included loss of teeth, bone segments, and even entire maxillae. Several factors may contribute to the increased risk for avascular necrosis in maxillary osteotomies, including significant repositioning, soft tissue flap design, multiple segments, small segments, hypotension, severance of the palatine blood vessels, and tears and perforations of the mucosal pedicles [7].

You et al. [8] demonstrated that in animal models there was a 50% reduction in the postoperative vascular flow, which returns to normal after 1 week and will increase by 70% above normal after the second week.

Teeth vitality may be an important and sensitive indicator in the diagnosis of aseptic bony necrosis at an early stage. Electrical pulp testing would not be a test for tooth vitality in osteotomy patients because the branches of the trigeminal nerve have been cut. It is of course also a very important aspect of these procedures that root apices not be severed or injured. Perhaps one of the helpful aspects of internal fixation is the requirement for more superior osteotomy cuts to provide adequate bone for fixation, which helps to avoid direct root apex damage. At the same time the placement of screws requires care to avoid this potential complication [9].

Superior osteotomy cuts may also reduce telescoping effects as the result of better bone contact. Fractured bone or locally damaged bone causes disruption of many blood vessels. This disruption results in local hemorrhage, followed by the formation of a blood clot. Osteocytes at both sides of the fracture die due to deprivation of blood perfusion [10]. Necrosis, due to ischemia of the traumatized bone, is a fact beyond the intact circulation and vessels tries to anastomose where possible [11].

The pulse oximeter is a noninvasive oxygen saturation monitoring device broadly used in medical practice for measuring blood oxygen saturation levels during the administration of intravenous anesthesia [12],[13]. It is easy in application and has capability of providing vital information about the patient's status [14],[15]. This technique has been used to detect pulpal vascular integrity in the tooth [12],[13]. Earlier studies by Schnettler and Wallace [12] reported a correlation between pulp and systemic oxygen saturation readings using a modified ear pulse oximeter probe on a tooth, pulp vitality is purely the function of vasculature health, so they recommended its use as a definitive pulp vitality tester.

Therefore, this study was carried out to record the approximate timing of revascularization of maxillary osteotomies and its impact on the healing process through measuring the dental blood flow oxygen saturation level using pulse oximetry.


  Patients and Methods Top


In this prospective clinical study, the research was conducted on eight patients with dentofacial deformities in whom the maxilla was included in their surgical correction. All patients were selected from the outpatient clinic of Oral and Maxillofacial Surgery Department. Ethical approval of the study was obtained from the Research Ethics Committee of Faculty of Dentistry in which the research was conducted.

The treatment plane of the selected cases was a surgical correction of the maxillary deformity using either Le Fort I osteotomy or anterior maxillary osteotomy.

Inclusion criteria

Adult patients over 18 years who have maxillary deformity which could not be corrected orthodontically.

Exclusion criteria

Patients subjected to previous maxillary surgery, or with any relevant systemic diseases that may disturb wound healing (e.g. diabetes, osteoporosis, etc.).

In all patients selected for this study, the pulpal blood flow of patient's index finger or thumb, maxillary centrals and canines was evaluated preoperatively, using the oxygen saturation level which was measured by the following method according to Abdelal [16].

  1. The patients were seated comfortably for 5 min.
  2. Intense light (e.g. operating light) was switched off to avoid signal interferences.
  3. The adult NellcorOximax sensor [Figure 1] was disinfected with ethyl alcohol and covered with transparent plastic film connected to the machine and activated.
  4. Oxygen saturation (SaO2) reading from the patient's index finger or thumb was recorded.
  5. SaO2 reading from teeth was recorded as follows:


    1. Patients were seated with head rest and instructed to be stable.
    2. Teeth were dried with cotton wool.
    3. The sensor was then positioned on the middle of the labial surface of the teeth (the emitting diode), whereas the receiving diode was positioned opposite and parallel to the red spot of the emitting diode on the middle of the palatal surface and stabilized in that position (hand-held technique).
    4. Data were recorded preoperatively and during the postoperative follow-up periods every week until complete revascularization which was obtained by getting the preoperative readings for 2 subsequent weeks.
    5. The collected data was tabulated and statistically analyzed using the statistical package for social science (version 22; SPSS Inc., Chicago, Illinois, USA).
Figure 1: A Nellcor OxiMax adult oxygen sensor used to measure the oxygen saturation level of patient finger and teeth.

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  Results Top


The SaO2 levels of patient's index finger, upper central incisors and upper canines were measured and recorded every week during the postoperative follow-up periods until revascularization occurs.

The mean values of the preoperative oxygen saturation levels [Table 1] were 98.7% for fingers, 94.5% for central incisors, and 96.4% for canines. The mean values of the oxygen saturation levels after 1 week postoperative were 98% for fingers, 0% for central incisors, and 0% for canines. There was a highly significant decrease when compared with the preoperative values; the difference was statistically significant at 5% level (P < 0.001).
Table 1: The preoperative oxygen saturation levels of all patients

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The mean values of the oxygen saturation levels after 2 weeks postoperative were 98% for fingers, 0% for central incisors, and 0% for canines. There was still a highly significant decrease when compared with the preoperative values; the difference was statistically significant at 5% level (P < 0.001).

The mean values of the oxygen saturation levels after 3 weeks postoperative were 99% for fingers, 40% for central incisors, and 55% for canines. There was significant decrease when compared with the preoperative values; the difference was statistically significant at 5% level (P < 0.001).

The mean values of the oxygen saturation levels after 4 weeks postoperative were 98% for fingers, 75% for central incisors, and 85% for canines. There was significant decrease when compared with the preoperative values; the difference was statistically significant at 5% level (P < 0.001).

The mean values of the oxygen saturation levels after 5 weeks postoperative were 98.5% for fingers, 85% for central incisors, and 94% for canines. There was insignificant decrease when compared with the preoperative values, the difference was statistically not significant (P = 0.173 and 0.097).

The mean values of the oxygen saturation levels after 6 weeks postoperative were 99% for fingers, 88% for central incisors, and 96.5% for canines. There was insignificant decrease when compared with the preoperative values, the difference was statistically not significant (P = 0.312 and 0.221) as shown in [Table 2].
Table 2: Comparison between preoperative and postoperative oxygen saturation levels in all patients

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  Discussion Top


Assessment of the maxillary blood flow postbony osteotomies is the critical factor determining the healing potential of the involved hard and soft tissues and thus the success or failure of the operation. Accordingly, the estimation of the vascularity of the cut bone is of crucial importance to minimize the postoperative complications that result from diminished blood circulation of the osteotomized bone.

These complications may appear as diminished dental sensitivity or devitalization, delayed soft tissue and bone healing, infection and wound dehiscence, or even bone necrosis and sequestration.

The hypothesis of this research is that by measuring the blood flow oxygen concentration reaching the dental pulps through the previously osteotomized bone segments, we can clinically predict the extent and the proper timing of revascularization, and thus the healing potential of the hard and soft tissues.

In case of delayed revascularization across the separated bony segments as measured indirectly with this technique, we have to immediately interfere to modify and improve the local and/or systemic conditions enhancing the blood supply, the local circulation and tissue perfusion, aiming to preclude or reduce the occurrence of irreversible complications, and failure of operation.

A previous study carried out by Teemul et al. [17] advocated the use of a hyperbaric oxygen treatment course at 14 and 18 days postoperatively to manage a case of wound infection and avascularity of the maxilla developed 1 week after. Therapeutic doses of pentoxifylline and vitamin E were also started to improve capillary blood flow. Pentoxifylline and its metabolites improve the flow properties of blood by decreasing its viscosity. In patients with chronic peripheral arterial disease, this increases blood flow to the affected microcirculation and enhances tissue oxygenation.

Our results showed that there was complete absence of revascularization across the osteotomized bone segments until the second postoperative week as denoted by absence of blood supply to the related teeth (centrals and canines). The readings of oxygen saturation levels were 0% in that time period.

The blood supply to the related teeth pulps started to gradually improve from the third postoperative week until the sixth week when it reached the maximum oxygen saturation values that are statistically nonsignificant when compared with the preoperative values.

During this time frame of 6 weeks of postoperative follow-up, there was a straight forward uneventful clinical healing conditions of all operated cases. No cases of bony sequestration, infection, or delayed healing were recorded in this study. Accordingly, we can find out that the clinical healing course is accurately matching the obtained values of pulpal oxygen saturation measured by the pulse oximeter during the follow-up periods.

Therefore, this study is in accordance with the research results of Meyer and Cavanaugh [9], who stated that teeth vitality may be an important and sensitive indicator in the diagnosis of aseptic bony necrosis at an early stage. Also it comes to an agreement with that of Epker [18],[19], who revealed that the exact condition of the dental pulp of the teeth involved in Le Fort I and anterior maxillary osteotomy is of great importance in deciding the sequelae of such teeth, this is possibly related to the degree of vascular impairment of the dental pulp and surrounding tissues.

Many authors studied the innervations of the teeth after maxillary orthognathic surgery by conventional pulp testers using cold, hot, or electrical current to indicate the vitality of the pulp sensory supply, rather than the vascular supply which determines the vitality of any tissue. They found that the nervous tissue which is highly resistant to inflammation may remain reactive, while other tissue degenerates. Sensory pulp testing may give false positive or false negative results. In addition, those types of testing may be painful to the patients. They also concluded that electrical pulp testing would not be a test for tooth vitality in osteotomy patients because the branches of the trigeminal nerve have been cut [9],[20],[21].

Recently, several methods to estimate microcirculation of the tooth pulp were introduced as pulse oximetry, spectrophotometer, or laser Doppler flowmetry. They are based on blood oxygen saturation levels of the pulpal blood flow [22],[23].

The pulse oximetry used in this study matches that used in the studies of Schnettler and Wallace [12], Severinghans and Kelleher [24], and Cobikrishna et al. [25], who considered it as a noninvasive safe and accurate oxygen saturation monitoring device that is widely used in medical practice for recording blood oxygen saturation level during the administration of intravenous anesthesia.

Schnettler and Wallace [12] studied the dental pulp of 49 adult patients with thermal, electrical, and oximetric techniques, and he found that the pulse oximeter indicated a pulse rate and oxygen saturation of vital teeth only and teeth with endodontic filling gave no response.

They further evaluated the sensitivity, specificity, positive predictive value, and negative predictive value of this device in comparison with thermal and electric pulp-testingmethods and concluded that pulse oximeter is an objective and accurate method of assessing pulp vitality [25],[26].


  Conclusion Top


Pulse oximeter is a valuable, simple, noninvasive, and inexpensive tool that could be used clinically to accurately measure the oxygen saturation level of the dental pulp and thus provides a great help in clinical evaluation of the revascularization process across the osteotomized bony segments. Accordingly, we recommend its routine use in similar situations.

In case of delayed revascularization, early prophylactic measures are recommended to enhance the soft tissue healing with local care aiming to preclude or reduce the occurrence of irreversible complications and failure of operation. Therapeutic doses of pentoxifylline and vitamin E could be used to improve capillary blood flow.

Urgent management of the operated site should be started to improve the local and systemic circulation if the 0% reading of oxygen saturation extended to the third postoperative week, or the value does not increase to more than 60% during the fourth week.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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2.
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3.
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4.
Greenberg A, Prein J. Considerations for bone healing in the craniomaxillofacial trauma patient. In: Greenberg AM, editor. Craniomaxillofacial fractures: principles of internal fixation using the AO/ASIF technique. New York, NY: Springer-Verlag; 1993.  Back to cited text no. 4
    
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Zhou Y, Hägg U, Rabie A. Concerns and motivations of skeletal class III patients receiving orthodontic-surgical correction. Int J Adult Orthod Orthognath Surg 2001; 16:7–17.  Back to cited text no. 5
    
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Turvey T, White R. Maxillary surgery. In: White RP Jr, Proffit WP, editors. Surgical-orthodontic treatment. St Louis, MO: Mosby; 1992. pp. 248–263.  Back to cited text no. 6
    
7.
Lanigan D, Hey J, West R. Aseptic necrosis following maxillary osteotomies: report of 36 cases. J Oral Maxillofac Surg 1990; 48:142–156.  Back to cited text no. 7
    
8.
You Z, Zhang Z, Zhang X. A study of maxillary and mandibular vasculature in relation to orthognathic surgery. Chin J Stomatol 1991; 5:263–266.  Back to cited text no. 8
    
9.
Meyer M, Cavanaugh G. Blood flow changes after orthognathic surgery: maxillary and mandibular subapical osteotomy. J Oral Surg 1976; 35:495–501.  Back to cited text no. 9
    
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Cohen S, Hargreaves KM. Pathways of the pulp. 9th ed. St Louis, MO: Mosby; 2006.  Back to cited text no. 14
    
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  [Full text]  
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Abdelal S. Evaluation of blood flow in the anterior maxilla after orthognathic surgery. Tanta Dent J 2008; 51:64–68.  Back to cited text no. 16
    
17.
Teemul T, Perfettini J, Morris D, Russell J. Post-operative avascular necrosis of the maxilla: a rare complication following orthognathic surgery. J Surg Case Rep 2017; 2017:rjw240.  Back to cited text no. 17
    
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Evans D, Reid J, Strang R. A comparison of laser Doppler flow-metric with other methods of assessing the vitality of traumatized teeth. Endod Dent Traumatol 1999; 15:284–290.  Back to cited text no. 22
    
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Jakubowska M, Matthews-Brzozowska A, Grotthus B, Szeląg A. Measurement of pulpal blood flow using laser Doppler flowmetry. Dent Med Probl 2006; 43:239–244.  Back to cited text no. 23
    
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Cobikrishna V, Tinagupta K, Kandaswany D. Evaluation of efficacy of a new custom made pulse oximeter dental probe in comparison with the electrical and thermal tests for assessing pulp vitality. J Endod 2007; 33:411–414.  Back to cited text no. 25
    
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