Effects of polymethyl methacrylate-based bone cement graft for treating excessive gingival display and its dimensional facial changes: 12-Month clinical study

Objective

to present a 12-month follow-up with photographic and tomographic analyses of the effect of polymethyl methacrylate-based bone cement graft (PMMA) in gingival exposure (GE) in patients with excessive gingival display (EGD).

Methods

Twelve patients with EGD were included. The PMMA was surgically placed. A frontal and lateral photograph protocol was performed at baseline (T0), 3 (T3), 6 (T6), and 12 months (T12) post-operatively. Soft tissue cone-beam computed tomography (ST-CBCT) was performed at T0 and T12. Measures included GE, length of the lip vermilion (LLV), lip shape (LS), nose width (NW), filter width (FW), nasolabial angle (NAS) while smiling, and nasolabial angle at rest (NAR). The height, thickness, and volume of the cement graft were also measured in the ST-CBCT. The comparisons were performed by Kruskal-Wallis test at 5 % of significance (p < 0.05).

Results

The height, thickness, and volume of the PMMA were respectively 12.84 ± 1.59 mm, 3.83 ± 0.53, and 1532.02 ± 532.52 mm3. PMMA significantly decreased GE from 8.33 ± 1.25 mm (T0) to 6.60 ± 0.93 mm (T12) (p < 0.01). NAR was 98.34 ± 9.28° at T0 and increased to 105.13 ± 7.33° at T12; however, the angle value was not statistically different (p = 0.08). LLV, LS, NW, FW, and NAS did not exhibit statistical differences between the baseline and follow-up periods.

Conclusions

PMMA significantly decreased GE in a 12-month follow-up without influencing adjacent soft tissue anatomical structures.

Dental and periodontal dimensions stability after esthetic clinical crown lengthening surgery: a 12-month clinical study

OBJECTIVES

To evaluate the stability of periodontal tissues 3 (T3), 6 (T6), and 12 (T12) months after esthetic crown lengthening (ACL) and the possible correlations between changes in those structures.

MATERIALS AND METHODS

Twenty individuals were evaluated through clinical assessment, photography, and tomography. Measurements included gingival margin (GM), clinical crown length (CCL), interdental papilla height (PH) and width (PW), gingival thickness (GT), bone thickness (BT), probing depth (PD), distance between alveolar crest and GM, distance between alveolar crest and cementoenamel junction. Nonparametric and correlation statistics were performed (p < 0.05).

RESULTS

CCL at T0 was 7.42 ± 0.70 mm and increased to 9.48 ± 0.49 mm immediately after ACL, but it decreased to 8.93 ± 0.65 mm at T12. PD decreased 0.60 mm from T0 to T6, and it increased 0.39 mm from T6 to T12. BT decreased 0.20 mm, while GT increased 0.29 mm from T0 to T12. Both PW and PH showed enlargement in T12. A positive moderate correlation was found between CCL/T0 and CCL/T12, GT/T0 and AC-GM/T12, BT/T0 and GT/T12. A few negative moderate correlations were PD/T0 and CCL/T12, PD/T0 and PH/T0, PD/T0 and BT/T12.

CONCLUSIONS

ACL procedure was effective. Although some rebound occurred, that was not clinically important. PD tended to reestablish its original length, partially due to a migration of GM during the healing period. Besides, a thickening of supracrestal soft tissues was observed.

CLINICAL RELEVANCE

The present study centers on the factors influencing the stability of periodontal tissues after esthetic crown lengthening, underscoring the procedure's influence on esthetics and biology and the need for careful treatment planning.

Finite element analysis of a newly designed miniplate for orthodontic anchorage in the maxillary anterior region

INTRODUCTION

Multiple force vector applications may be indicated when an arch segment or en masse intrusion is needed. This finite element method study aimed to evaluate the total deform the stress yielded in the bone and the miniplate when forces with different directions and magnitudes were applied.

METHODS

First, the prototyped skull model was fabricated on the basis of computed tomography (CT) scans. On this model, the miniplate was fixed, and orthodontic appliances were attached. Then, a 3-dimensional finite element model was constructed by reproducing the characteristics of the physical model. Seven situations were investigated, which diverged in the point of force application, the direction and the number of force vectors, and the force magnitudes.

RESULTS

When the force was applied at 1 point, similar behavior could be observed concerning the deformation and the stress in the miniplate, the maxilla, and the screw holes. Most deformation and stress appeared in the transmucosal arm below the step bend and at the force application point. The angled vectors (-45° and 30°) presented smaller values concerning the vertical vectors. Similar or better performances could be observed when the forces were simultaneously applied at the 2 points.

CONCLUSIONS

The newly designed miniplate showed similar or improved performances when multiple vectors were applied at the 2 points simultaneously compared with the force applied at 1 point. This newly designed miniplate may present improved performance in a clinical situation when multiple forces are demanded.

Aesthetic perception of smile in long face pattern patients who underwent maxillary impaction with miniplates or orthognathic surgery

INTRODUCTION

The gummy smile is perceived in 10% of the population aged 20 to 30 years old, and it causes an aesthetic imbalance in the smile. This study investigated the existence of differences in the aesthetic perception of the smile after correcting the gummy smile using two different techniques: orthognathic surgery for maxillary impaction and miniplate-aided orthodontic impaction.

METHODS

Photographs of 16 Long Face Pattern female patients were evaluated by 56 oral and maxillofacial surgeons, 56 orthodontists, and 56 laypeople before and after the treatment with one of the two techniques. These photographs were standardized using the Photoshop program, randomly organized, and then presented to the evaluators via the Google Meeting® application in the PowerPoint® program. To evaluate the attractiveness of the smile, the Visual Analogue Scale (VAS) was used. To analyze the intra and inter-examiner concordances, Spearman's correlation and Kendall's concordance tests were used, respectively. For intergroup comparison, the Friedman test was used, with a 5% significance level.

RESULTS

For all three groups of evaluators, the post-treatment evaluation results were superior to the results before the treatment: surgeons and orthodontists assigned higher scores for surgical cases and laypeople for orthodontic cases.

CONCLUSION

From a clinical point of view, there was no difference between the results of both techniques with regard to the aesthetic perception of smiles. A gingival exposure ranging from zero to two millimeters was considered the most aesthetic for all evaluators.

Effect of orthodontic maxillary posterior en masse intrusion anchored with miniplates on maxillary sinuses volume. Retrospective CBCT study

OBJECTIVE

To evaluate, by means of cone beam computed tomography (CBCT), the volume change of maxillary sinuses in patients that underwent orthodontic maxillary posterior en masse intrusion anchored with miniplates.

MATERIALS AND METHODS

The sample consisted of pretreatment (T1) and posttreatment (T2) CBCT scans obtained from 14 patients (4 male and 10 female), with a mean age of 32.4 years, that underwent orthodontic maxillary posterior en masse intrusion anchored with miniplates in the zygomatic crest. The mean treatment duration was 20 months and the mean intrusion movement was 2.4 mm. Maxillary sinus volume was measured by means of the software ITK SNAP (version 3.8.0) in T1 and T2 CBCT scans. The changes in sinuses volume were calculated by T1-T2 values. Data were analyzed statistically with Wilcoxon test at 5% of level of significance and the method error was analyzed with Wilcoxon test, intraclass correlation and Dahlberg's formula.

RESULTS

The mean difference (T1-T2) was -242.85 mm³ (p = 0.396) for the right sinus and -32.5 mm³ (p = 0.875) for the left sinus. A slight increase in the volume of the sinuses was shown although these results were not statistically significant.

CONCLUSION

The orthodontic maxillary posterior en masse intrusion anchored with miniplates did not influence significantly the maxillary sinus volume.

New perspective on Herbst therapy for skeletal Class II malocclusions: a proposal for maxillary protrusion management

Angle Class II malocclusions may present morphologic deviations originated from the maxilla, mandible, or both. Since its reintroduction by Pancherz, the Herbst appliance has demonstrated effectiveness in the management of patients with mandibular deficiency. Because of the intermaxillary anchorage, the action of mandibular advancement provokes simultaneous reaction of maxillary restriction, similar to high-pull headgear. This aimed of this report is to compare two cases treated in two phases. In the first interceptive phase, the transverse problem was corrected by rapid maxillary expansion, which was followed by a Herbst appliance for mandibular advancement; in the second corrective phase, the cases were finished with fixed appliances. Although Herbst appliances were used in both patients, one patient with maxillary protrusion and another with mandibular deficiency, their use targeted different types of skeletal discrepancies. This difference allowed for the comparison of treatment effects, and although both patients had their malocclusion corrected, it seems reasonable to conclude that the final outcome was more favorable for the patient with maxillary protrusion.

Fatal dissecting aneurysm of the internal carotid artery with delayed symptoms following facial impact

A fatal dissecting aneurysm of the internal carotid artery occurred in a 16-year-old male following facial impact in an automobile accident. The patient showed no neurologic deficit until two days after the automobile accident, when he suddenly started having seizures and developed right-sided hemiparesis. There was no evidence of direct trauma to the neck externally or internally. The only injuries observed in the head and face were two skin lacerations in the chin area. His condition rapidly deteriorated, and he expired on the fourth hospital day. The gross and microscopic findings for the internal carotid artery are presented. The possible mechanisms for the vascular lesion and a review of the literature are discussed.

Fatal thrombosis of internal carotid artery following minor blunt trauma to the neck

Fatal traumatic thrombosis of the left internal carotid artery occurred in a 38-year-old man following minor blunt cervical trauma during an altercation. There was no external injury observed on the head, face, or neck. Neurologic deficit developed soon after the injury, which progressed to right hemiplegia. His condition deteriorated and he expired on the sixth hospital day. The gross and microscopic findings of the internal carotid artery are presented and the significance of minor cervical blunt trauma and the possible mechanism for the vascular lesion are discussed.