Changes in Dental Pulp Blood Flow of Different Maxillary Tooth Types After Le Fort I Osteotomy

Recommendations to minimize tooth root remodeling in patients undergoing maxillary osteotomies

The purpose of this study was to report root remodeling/resorption percentages of maxillary teeth following the different maxillary osteotomies; i.e. one-piece, two-pieces, three-pieces Le Fort I, surgically assisted rapid palatal expansion (SARPE). The possibility of relationships between root remodeling and various patient- and/or treatment-related factors were further investigated. A total of 110 patients (1075 teeth) who underwent combined orthodontic and orthognathic surgery were studied retrospectively. The sample size was divided into: 30 patients in one-piece Le Fort I group, 30 patients in multi-pieces Le Fort I group, 20 patients in SARPE group and 30 patients in orthodontic group. Preoperative and 1 year postoperative cone beam computed tomography (CBCT) scans were obtained. A validated and automated method for evaluating root remodeling and resorption in three dimensions (3D) was applied. SARPE group showed the highest percentage of root remodeling. Spearman correlation coefficient revealed a positive relationship between maxillary advancement and root remodeling, with more advancement contributing to more root remodeling. On the other hand, the orthodontic group showed a negative correlation with age indicating increased root remodeling in younger patients. Based on the reported results of linear, volumetric and morphological changes of the root after 1 year, clinical recommendations were provided in the form of decision tree flowchart and tables. These recommendations can serve as a valuable resource for surgeons in estimating and managing root remodeling and resorption associated with different maxillary surgical techniques.

Effect of Orthognathic Surgery On Pulp Blood Flow and Pulp Sensibility: A Prospective Control Trial

INTRODUCTION

Orthognathic surgery has the potential to compromise the vitality of the teeth. This paper aims to assess changes in pulp blood flow (PBF) and pulp sensibility (PS) of the anterior dentition following orthognathic surgery and to assess the influence of the proximity of the surgical osteotomy on the PBF and/or PS.

METHODS

Twenty-six patients undergoing orthognathic surgery (Le Fort I or bilateral sagittal split osteotomy [BSSO]) were compared to sixteen control patients treated by fixed appliances only using Laser Doppler flowmeter (LDF) and thermal testing (CO2 snow). Surgery patients were tested at T1 (presurgery), T2 (4-5 weeks postsurgery), T3 (3 months postsurgery), and T4 (6 months postsurgery). Control patients were tested at T1 (pretreatment), T2 (6 months posttreatment), T3 (12 months posttreatment), and T4 (18 months posttreatment). Differences between the maxilla and mandible were assessed.

RESULTS

No differences in PBF or PS were recorded in the control group. In the surgery group, both jaws followed the same pattern after surgery, an initial decrease at T2 followed by a gradual recovery to pretreatment PBF levels with no significant difference between T1 versus T4 in both jaws. No difference in PBF was observed between the maxilla and mandible at any testing time interval.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PBF and PS of the anterior dentition was severely affected immediately postsurgery, followed by a gradual increase to full recovery. This pattern of recovery was exhibited in both jaws. A negative sensibility response or discoloration should not be seen as an indication of irreversible ischemic pulp changes. Monitoring for at least 6 months or using LDF as a confirmatory test is required before any irreversible endodontic treatment is to be considered.

Dental discoloration following Le Fort 1 osteotomy, a systematic review

INTRODUCTION

This study was conducted to review current knowledge concerning factor and how to proceed with dental discoloration after Le Fort 1 osteotomy (LF1O).

MATERIAL & METHODS

A systematic search of the literature was performed in PubMed/Medline and Cochrane library until December 1, 2020 using the following key words: "dental discoloration and osteotomy", "dental discoloration and Le Fort", "dental discoloration and orthognathic", "dental discoloration and surgery", "tooth discoloration and osteotomy", "tooth discoloration and Le Fort", "tooth discoloration and orthognathic", "tooth discoloration and surgery".

RESULTS

705 studies were located by initial screening; 232 were duplicate, 468 did not meet the eligibility criteria, leaving 5 studies. The post-operative follow-up period of the included studies ranged from 6 months to 2 years.

CONCLUSION

The present revue found dental discoloration can occur after LF1O in 3.56% of the cases. The follow-up before treatment should be around one years. If the discoloration persisted and pulpal sensibility test is negative, the tooth should be treated. If the pulpal sensibility test is positive, follow-up should be carry on.

Color changes of maxillary and mandibular incisors following surgical orthodontic treatment : A prospective controlled clinical pilot study

OBJECTIVE

To assess possible color changes of natural teeth after surgical orthodontic treatment.

METHODS

This prospective controlled clinical pilot trial included 6 consecutively treated surgical orthodontic patients with class III malocclusion and neutral vertical relation (ST: surgical treatment), 3 of which received double jaw osteotomies (SGI: surgical subgroup I) and 3 received single mandibular sagittal split ramus osteotomies (SGII: surgical subgroup II). Eleven untreated individuals (UC: untreated control) and 9 individuals who received conventional comprehensive orthodontic treatment only (OC: orthodontic control) served as controls. Tooth color measurements were performed using a reflectance spectrophotometer on the upper and lower incisors before the initiation of the surgical orthodontic treatment (T1) and after its completion (T2). Primary endpoint was ∆E* (T1-T2) of summarized CIE-L*a*b* color differences. The null hypothesis of this study was that there is no statistically significant change in total tooth color difference ∆E* CIE-(L*a*b*) in vivo at baseline and following surgical orthodontic treatment.

RESULTS

There was a statistically significant increase in ∆E* (T1-T2) in the ST group compared to the UC and OC groups. Single mandibular surgery had a stronger effect on the lower teeth in comparison to double jaw surgery, while Le Fort I osteotomy, as part SGI, had a stronger effect on the upper teeth. Despite statistical significance, the majority of mean values of these color changes were lower than the threshold value of color alterations considered to be perceivable by the naked eye in a clinical setting (3.7 ∆E units), with the exception of the mandibular incisors in SGII, where this threshold value was slightly exceeded.

CONCLUSIONS

Orthognathic surgery showed a measurable effect on tooth color. However, esthetic disturbance or patient discomfort based on these color and lightness alterations are unlikely, due to their small impact and low perceptibility in a clinical setting.

Tomographic analysis of nasomaxillary and zygomaticomaxillary buttress bone thickness for the fixation of miniplates

The purpose of this study was to evaluate the bone thickness of the nasomaxillary and zygomaticomaxillary buttresses to identify the most favourable region for the installation of miniplates. Bilateral tomographic images of 103 individuals were evaluated, for a total of 206 nasomaxillary and zygomaticomaxillary buttresses. Measurements of bone thickness were performed in the parasagittal reconstructions along three vertical lines on the nasomaxillary buttress (21 measurement points) and four vertical lines on the zygomaticomaxillary buttress (28 measurement points). The vertical line measurements for each buttress were compared using the Kruskal-Wallis test. Spearman's correlation coefficient was used to determine the correlation between the thicknesses obtained and patient sex and side (right/left). The level of significance adopted was 5%. The nasomaxillary and zygomaticomaxillary buttresses presented statistical differences in thickness at their respective points (P=0.001). The analysis of the nasomaxillary buttress showed that the thicker bone for the installation of miniplates follows the long axis of the upper canine at a distance of 3mm from the root apex. For the zygomaticomaxillary buttress, thicker bone to install miniplates was found distal to the distobuccal root of the first molar, at a distance of 3.5mm from the limit of the infraorbital foramen.

Pulpal and Periodontal Tissues Changes Associated with Le Fort I and Sagittal Split Ramus Osteotomies: A review

Introduction:

Le Fort I and sagittal split ramus osteotomies are the most commonly performed orthognathic surgery procedures on the maxilla and mandible, respectively.

Techniques:

Despite progress in the techniques, these procedures may still be associated with morbidity, expressed as inflammation, inadequate bony union, periodontal damages or in extreme cases even total bone loss.

Discussion:

Through a comprehensive review of the literature, the influences of maxillary and mandibular surgery on Pulpal Blood Flow (PBF), pulp sensitivity and pulp vitality are examined. Moreover, adverse effects of maxillary surgery on tooth color and periodontal tissues are also reported. The effects had a variety of expression. Concerning maxillary surgery, some studies showed an initial increase in PBF followed by a decrease to the baseline or even lower levels after 1-3 months. Other studies found an initial decrease in PBF followed by an increase soon after. There were also studies that showed no significant PBF changes, in contrast.

Conclusion:

Concerning mandibular surgery, a recent study showed a decrease in PBF immediately after sagittal split ramus osteotomy. Some authors detected tooth discoloration of maxillary teeth after Le Fort I osteotomy. Root resorption and root injury were also detected, but were of minor significance. Usually, these adverse effects derive from injury of the vessels of the palatal pedicle. This pedicle should be maintained intact for the avoidance of blood flow impairments. In addition, the descending palatine artery should be protected during maxillary surgery procedures in order to maintain the highest possible blood flow on the maxillary teeth.