HIGH-SPEED OR CONVENTIONAL DENTAL ENGINES FOR THE REMOVAL OF BONE IN ORAL SURGERY. I. A STUDY OF THE REACTIONS FOLLOWING REMOVAL OF BILATERAL IMPACTED LOWER THIRD MOLARS

A reliable and reproducible method for repositioning 3D images to calculate changes in facial volume after orthognathic surgery

PURPOSE

An accurate, reproducible method to calculate post-operative facial swelling in patients who have undergone orthognathic surgery is important to evaluate the effects of different therapies and surgical techniques on edema. The purpose of this study was to describe such a method and assess its reliability.

MATERIALS AND METHODS

A prospective study of patients undergoing orthognathic surgery was conducted. 3D facial photographs were taken on these patients immediately postoperatively, and again at least 21 days later using the 3DMD face system (3DMD LLC., Atlanta, GA, USA). These were cropped using specific anatomic points and the difference in facial volume between the photographs was calculated. Intra-rater reliability and inter-rater reliability were assessed using the Intraclass Correlation Coefficient (ICC).

RESULTS

30 patients were included in the study for analysis. When the difference in facial swelling was calculated twice by the same rater, the mean difference between the two measurements was 4.0 ± 4.2 mL. When calculated by two separate raters, the mean difference was found to be 5.0 ± 3.8 mL. The ICCs for intra-rater and inter-rater reliability were excellent at 0.979 and 0.981 respectively.

CONCLUSION

This method allows for reproducible calculation of post-operative facial swelling and could be useful to evaluate the effects of different therapies used to limit swelling and to track the resolution of swelling. It can also potentially be used as a visual aid for patient counseling during the pre-surgical visits.

A gnathodynanometer as an objective means of pain assessment following wisdom tooth removal

There appears to be no information concerning changes in bite strength following wisdom tooth removal. A gnathodynanometer was constructed, calibrated and then tested on 20 normal subjects. Sixty five patients scheduled for third molar surgery were assessed by this device immediately before operation and on the seventh post-operative day. Post-operatively, they were asked to complete a McGill pain questionnaire (MPQ) and indicate their present pain on a numerical rating scale (NRS). Bite strength was reduced in all cases. The side which was most painful tended to have the larger reduction. The reduction in bite strength was found to have a highly significant correlation with the numerical rating scale and a significant correlation with the sensory descriptors of the McGill pain questionnaire. It would appear, therefore, that the gnathodynanometer holds promise as a research tool in oral surgery.

Volumetric determination of extraoral swelling from stereophotographs. A method study in the buccal area

A stereophotographic method for volumetric determination of the extraoral swelling after mandibular third molar removal is developed. The method error was 1.0 cm3. Compared to the size of the maximal swelling after removal of impacted wisdom teeth, this error is considerable. The technique can, however, be improved and furthermore applied to measurements of volume changes in other cranio-facial areas, as well as in other parts of the body.

Quantitation of experimental postsurgical edema

Many oral surgical procedures are followed by varying degrees of edema. Although numerous methods of minimizing swelling have been advocated, no technique has gained complete acceptance. A major problem has been the inability to document the efficacy of suggested treatments convincingly. The present study quantitates edema by measuring differences in percentage of water content between operated and unoperated tissues over a period of one week. Percentage difference in water content peaked by 48 to 72 hours and was followed by gradual resolution. By use of this model system, a steroid-induced, dose-dependent suppression of postsurgical swelling was confirmed.

The development of a method of assessing swelling following third molar surgery

A method of measuring post-operative facial swelling following third molar surgery should satisfy the following criteria. Firstly, the accuracy should be assessed, secondly the measurement should be in volume units, and thirdly the method should be both practical and ethical in the clinical situation and not limited by static apparatus. No published method satisfies all of these criteria. In an attempt to develop a satisfactory method, direct physical measurements using a face bow, ultrasound and portable stereophotogrammetry were investigated. None of these three methods was limited by static apparatus. Portable stereophotogrammetry could not be used because of variations in posing for which a correction could not be applied. Repeated measurements on non-operated subjects showed that the face bow was more accurate than the ultrasound method at a single measurement site. Therefore, the face bow method was developed to give volume measurements in cubic centrimetres by using nine measurement sites at the intersections of a square grid located over the swelling. The mean difference between two readings taken on separate occasions on non-operated subjects was -0.94 cc (s.d. +/- 1.90). The mean swelling measured at twenty third molar operation sites was 23.19 cc. It is concluded that this face bow method satisfies the criteria laid down.

The interrelation of postoperative complaints after removal of the mandibular third molar

Quantitative data on pain, trismus, and swelling after removal of a mandibular third molar are presented. The population of 932 patients included both extractions and surgical removals. Frequency distributions of trismus and pain are given. For all complaints the behavior of the average value as a function of time is presented and these functions are compared with each other. For all values measured on the 3rd and 4th posttreatment days, correlation and regression coefficients for the effects were calculated. It is concluded that there exists a rather strong, but time-dependent, interrelationship between the complaints.

A photographic method of assessing swelling following third molar removal

No objective method for measuring postoperative swelling both simply and reliably is known from the literature. The method described in this article measures the degree of swelling indirectly by comparing tracings of pre- and postoperative photographs printed full-size. The photographs taken are standardized and full-face. The head is reproducibly fixed by means of a bite impression and two rings. One ring is mounted on a table on which the camera also is fixed. At the other, mobile, ring the bit impression is fixed. Three-point contact in the correct position between the two rings is signalled electrically, so that the head is in the correct position and the photograph can be taken. The advantage of this method over a rigis connection between bite fork and fixation stand on the table is that distortion or even bending of the fork and connecting bar is not possible. Experience with this method shows that in 95% of the patients photographed the picture was exactly reproducible. Measuring non-operated test persons revealed the reproducibility of the cheek contour to be better than 0.2 mm. The error made when tracing the photographs is of about the same magnitude.

Bilateral surgical removal of impacted lower third molar teeth as a model for drug evaluation: a test with ibuprofen

It was considered that double-blind crossover studies of therapeutic efficacy after acute injury could well be done in patients who required surgical removal of impacted wisdom teeth from both sides of the lower jaw. In the present trial 24 healthy patients received either placebo or ibuprofen (Brufen: 400 mg three times daily), a non-steroidal anti-inflammatory agent, for 5 days commencing the day before surgery. Treatments were given on the two occasions when impacted wisdom teeth were to be removed from one side or other of the lower jaw. A number of objective and subjective parameters were recorded for paired comparison of the post-operative courses, including swelling, trismus and pain. A mechanical device which allows simple and accurate measurement of cheek swelling is described. On the 1st, 3rd and 5th post-operative days in the ibuprofen group the measured swelling averaged 93, 89 and 82%, respectively, of that in the placebo group; the corresponding alpha-values were 0.35, 0.06 and 0.07. Patients with less swelling after ibuprofen were not always those with a high serum concentration of the drug. Ibuprofen significantly reduced pain on the day of the operation. This may at least partly account for less trismus and the preference of the patients for their post-operative courses with ibuprofen. Examination of various haematological parameters did not reveal any significant difference between the two operations. Subjective scores indicated that neither wound-healing nor bleeding was affected by ibuprofen, nor were any side effects detected.