Facial edema is the most common and distressing postoperative sequelae following surgical removal of the impacted mandibular third molars. Although these signs of inflammation are essentially beneficial and transient, the patients are always unpleasant because of disfigurement and dysfunction 1. It is also uncomfortable, unaesthetic, may compromise the airway, and can impair healing of the wound owing to restricted local circulation, which favors bacterial growth. It also contributes considerably to trismus and pain because of increased tension in the tissues 2–4.
Fleuchaus 5 and Cameron 6 described the course of facial edema, and claimed that the peak of facial swelling seemed to occur at 30 h, and started to subside at 48 h postoperatively. Swelling disappeared in nearly all patients by the seventh postoperative day. On the contrary, Pöllmann 3 followed up the course of postoperative swelling and claimed that the swelling decreased after the second day up to the fifth postoperative day. The swelling peaked around the seventh day, and then it began to decrease again. He also concluded that the swelling did not diminish continuously but decreased in periodic modes.
Allam 7 concluded that the maximum swelling corresponded to a line between the angle of the mandible and the corner of the mouth (A–C), followed by a line between the angle of the mandible and the mentum (A–M), whereas Schneider 8 claimed that the swelling usually occurred over the outer surface of the jaw and is most pronounced at the anterior region of the masseter muscle. Hooley and Francis 9 defined the point of maximum swelling after traumatic mandibular third molar surgery was 50° from an angle formed by a horizontal line drawn through the corners of the mouth and the midline.
Many devices and methods to study facial edema have been advocated by many authors, but most of them lacked sensitivity, simplicity, and reproducibility 10–12. Visual assessment or clinical estimation for evaluation of postoperative swelling as no swelling, just visible swelling, moderate swelling, and severe swelling in relation to the other side of the face as a reference was used by many authors 8,13,14.
Quantitative measurements of facial swelling are often required in research work in oral and maxillofacial surgery to objectively follow development in the swellings, their magnitude, and duration. Such measuring methods would be of value when judging how the various etiological and pathogenic factors influence postoperative edema, infectious swellings, edema resulting in surgery, and so forth, particularly correlation between visual assessment and objective that was not proved 15.
Various objective techniques were used to assess postoperative swelling. Forman 16 developed a radiographic method by painting the skin of the face and upper neck of the patient with barium sulfate suspension, and the swelling area could be measured by comparing both preoperative and postoperative anteroposterior radiographs.
Holland 17 reviewed three methods for measuring postoperative swelling: Face bow method as the one used in prosthodontics. The subject was asked to occlude the teeth in centric relation into the softened impression compound on the bite fork. Each location point was adjusted and the position was recorded on a millimeter scale, allowing relocation in the same position on different occasions. The edema was assessed through counting the mean of special cads displaced laterally because of postoperative swelling. Ultrasound method: Ultrasound with a wave frequency of several million cycles per second was used to estimate the cheek thickness preoperatively and postoperatively; however, the author found that this technique was more variable. Stereophotographic method: Stereophotographs were taken for the cheek using stereophotogrammetry camera, preoperatively and postoperatively at different intervals. The author stated that ‘the face bow device was the most accurate method for measuring the swelling volume on the basis of its good reproducibility, when compared with other two methods’.
A photographic method was advocated by some authors 11,18. They used full face photographs taken at a fixed distance, and preoperative and postoperative pictures were compared. However, Milles et al.12 stated that ‘the problem with all photographic methods are that they provide a two dimensional image of a three dimensional swelling’. He also developed the facial plethysmograph for measuring postoperative edema as a three-dimensional method, and concluded that this method is more accurate than the photographic one.
Linear facial measurements between different facial landmarks using tape were used by many authors 3,7,19 or by using thread or silk suture 12,20, and the edema was evaluated by the changes in these linear measurements preoperatively and postoperatively.
Complicated techniques such as MRI and optical surface laser scanners were used to record and quantify facial soft tissue changes. These techniques are associated with high costs, and the need for complex machinery and the length of time excludes them from being used in routine practice 21,22.
Some investigators 5,8 have attempted to quantify facial swelling using calipers of various types. Fleuchaus 5 quantified postoperative edema by measuring the thickness of the cheek on the side to be operated on; one arm of the caliper was inserted in the lingual embrasure between the lower first and second mandibular molars, whereas the other arm was adjusted to lightly touch the skin of the cheek. Schneider 8 used a caliper to measure the total width of the face at the anterior border of the masseter muscle. The arms in these calipers are fixed using a sit screw, which is usually loosened by time. The caliper should be removed first before taking its reading on a tape, with a possibility of measurement changing during removal. In addition, the readings are in millimeters that is not sensitive enough.
Most of the above-mentioned methods and techniques either lack accuracy and reproducibility, are complicated and time consuming, or expensive. This study aimed to introduce and evaluate the accuracy of especially designed caliper with dial readings, which measure the cheek thickness in 0.01 mm (10 μm) for the assessment of postoperative edema after surgical removal of the impacted mandibular third molar.
Materials and methods
The present study was conducted on 32 patients presented at the Department of Oral and Maxillofacial Surgery, Faculty of Oral and Dental Medicine, Cairo University, seeking removal of the impacted mandibular third molar.
Cases selected for this study were class I position B (according to Pell and Gregory classification) 23 horizontal impacted mandibular third molar teeth that have arbitrary the same difficulty and operative time.
All patients were informed about the surgery for removal of the impacted tooth and they gave their approval to participate in this study with a written consent. The patients were diagnosed on the basis of clinical (Fig. 1) and radiographic examinations using digital panoramic radiography to assess the position of the impaction, the potential surgical difficulty, and the presence of any pathological lesions (Fig. 2).
The surgical procedures were performed under articaine 4% with felypressin vasoconstrictor (3M Deutschland GmbH, Neuss, Germany) local anesthesia, using mandibular block technique. The surgical flap used in this study was a conventional triangular flap. Bone guttering was performed at the distal and buccal aspects of the impacted tooth, using a low-speed surgical bur on a straight headpiece under copious amount of irrigation (Fig. 3). After tooth delivery, the tooth follicle was removed, sharp bony edges were smoothened out using bone file, wound toilet was carried out, and the flap was repositioned and sutured using 3/0 black silk suture (Assut Medical Sàrl, Pully/Lausanne, Switzerland). All patients were recalled on the second, fifth, and seventh postoperative day for the assessment of edema, and if any patient failed to return on the recall days they were excluded from the study.
Double assessment techniques were performed to evaluate postoperative edema; our caliper and the linear measurements, and then the results of both the techniques were compared and correlated to test the accuracy of our caliper.
(a) The newly designed caliper is modified from the calipers used originally from that used for thickness measurement in manufacture. This modification was carried out to suit its application in the oral cavity to measure the cheek thickness. This caliper has dial indicator graduated in 0.01 mm (10 μm), which is considered very sensitive to minute changes. New removable tips at the caliper ends were added to be easily sterilized and have an interchangeable character to be used in both the right and left sides, and can still directly read the caliper dial (Fig. 4). It has one pointed tip placed in a hole in a lingual acrylic splint opposite to the distal part of the second molar at the level of its cervical line fabricated preoperatively and used in all measurement sessions (Figs 5 and 6). The other rounded tip placed on the outer surface of the cheek at the masseter muscle at the A–C and opposite to the other tip arbitrarily lies at the same level 7,8. The arms of the caliper open and close using a horizontal screw to allow the outer tip of the caliper not to pit on the edematous cheek and allow taking the dial reading when the tip of the caliper just touches the cheek at the predetermined point. Care should be taken to ensure that both tips of the caliper are in a line parallel to a mandibular occlusal plane, and the patient is asked to close his teeth on the caliper arm during the measurement to ensure reproducibility (Fig. 7). The preoperative measurement was considered as baseline value, and the difference between each postoperative measurement and the baseline indicates the swelling for that day.
(b) Linear facial measurement was evaluated by the tape method described by Gabka and Matsumura 24. Three measurements were taken between five reference points: tragus, soft tissue pogonion (T–P), lateral corner of the eye, angle of the mandible (A–L), tragus of the ear, and corner of the mouth (T–C), preoperatively, and on the second, fifth, and seventh postoperative days (Fig. 8). The preoperative sum of the three measurements was considered as the baseline. The difference between each postoperative measurement and the baseline indicated the facial swelling for that day.
The study was approved by ethical Giacometti of Faculty of Oral and Dental Medicine, Cairo university, Egypt.
Data were presented as mean and SD values. Pearson’s correlation coefficient was used to determine significant correlation between cheek thickness and linear measurements. The significance level was set at P-value of 0.05 or less. Statistical analysis was performed with IBM (IBM Corporation, New York, USA) SPSS and Statistics version 20 for Windows (SPSS Inc., an IBM Company, Chicago, Illinois, USA).
The current study was conducted to compare between the facial linear measurements and a specially designed caliper measuring the cheek thickness for evaluation of the facial edema following odontectomy of the mandibular third molar and correlate the two measurements. All cases showed uneventful healing without wound dehiscence; however, two cases showed alveolar osteitis that were treated by saline irrigation and alveogel loose pack every other day till the signs and symptoms disappeared. The results showed that the peak of maximum edema in all patients measured using both linear and caliper measurements was on the second postoperative day, and started to decrease gradually, and by the end of the seventh postoperative day there was still a very little amount of edema present measured by both techniques.
The mean and SD values of linear measurements were 12.86±0.80, 13.18±0.76, 13.02±0.83, and 12.90±0.85 cm preoperatively after 2, 5, and 7 days, respectively (Tables 1).
Cheek thickness caliper measurements
The mean and SD values of cheek thickness measurements were 3.20±0.38, 3.74±0.31, 3.42±0.36, and 3.31±0.37 cm preoperatively after 2, 5, and 7 days, respectively (Table 2).
Correlations between linear and cheek thickness measurements
There was a nonstatistically significant positive (direct) correlation between cheek thickness measurements and linear measurements preoperatively after 2, 5, and 7 days postoperatively (P=0.084, 0.075, 0.058, and 0.110, respectively) (Table 3).
In oral and maxillofacial surgery, particularly in research work, being able to measure quantitatively the facial swelling is very helpful, especially when the effects of various surgical approaches or drug regimens on facial swellings are to be assessed 4. Holland 17 set the criteria for an ideal objective method for measuring facial swellings. He believes that the method should be accurate, its measurements should be in units, practical, and imposes no logistic problems in clinical trials, simple, and finally, it should be ethical. Although numerous methods have been devised to provide objective measurement of facial swelling, many are imprecise, and others more complex, expensive, and difficult to standardize 10,12,15,25.
The present study used the method of repeatable and reproducible facial linear measurement already tested and the most commonly used in facial swelling assessment and precisely quantifies the changes in facial volume 24. This method provided a series of data points utilizing defined fixed landmarks on the face and proved to be an accurate method, and therefore I used it in this study and correlated its measurement with our caliper readings.
Our caliper is a method that measures the thickness of the edematous cheek at the point or the small area of expected maximum swelling at the masseter muscle near its anterior border lateral to the third molar 15. This small area is predetermined preoperatively using indelible marker, and maintained at all follow-up periods to be used in all postoperative intervals, and therefore the measurement can be reproducible. Our caliper has a dial graduated in 0.010 mm (10 μm) and its reading can be taken directly during its application. This caliper differs from the other similar calipers as these calipers need to be removed first, with the possibility to disturb the measurement, and also their measurements are taken in millimeters that are less sensitive than the others 5,8.
However, our method, like all other methods of facial swelling measuring, lacks the ability to trace intraoral swellings; it also suffers the same shortcoming of inability to trace swellings at every site in the face 26. It measures the cheek thickness at the point or area of expected maximum edema determined by many authors preoperatively 7–9, and therefore it gives a real indication about changes in facial swelling.
This caliper is noninvasive, and its use does not impose any logistic problems in clinical trials, as it requires no complicated procedures or projection equipment. In addition, the mathematics involved in making objective assessments of changes in swelling size is simple. The removable tips allow us to sterilize the working tips without harming the caliper dial. The interchangeable tips also allow us to use the caliper on both sides of the jaw and still read the caliper dial directly and easily.
However, some of the other methods neglected studying the possible effect of changes in tissue tension and mandible position that can occur in measuring sessions 26, our caliper measurement was taken while the patient is relaxed and closes his mouth on the caliper arms, and the outer arm just touches the skin surface, and therefore the tissue tension and effect of changes in mandibular position was minimum.
On comparing the peak of maximum postoperative swelling measured by linear measurements and our caliper, we found that in both methods the peak of maximum swelling was on the second postoperative day. These results agree with most of the other authors who studied the postoperative edema following surgical removal of the impacted mandibular third molar with different methods of assessment and concluded that the peak of maximum edema was at the second postoperative day 3,5,6. In addition, on comparing the readings of both methods at all postoperative follow-up periods, we found that both techniques showed almost the same percentage of facial measurement changes at all follow-up intervals.
From the results of both linear and our caliper measurements, there was a positive correlation between readings of both methods, and this positive correlation means that our caliper is an accurate tool for assessment of facial swelling in comparison with the linear method.
Disposable sterilized plastic tips, similar and standardized to the stainless steel one, is now under manufacture to be more convenient in use.
The author acknowledges the Arab British Dynamic Research and design Sector of Arab Organization Industry (ABD) for their cooperation and great help to accomplish this caliper.
Conflicts of interest
There are no conflicts of interest.
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