Topography of the greater palatine artery and the palatal vault for various types of periodontal plastic surgery

Increased safety in periodontal surgery: Doppler ultrasound for detection of relevant palatal blood vessels-A proof-of-concept and cross-sectional study

AIM

To evaluate the suitability of a Doppler ultrasound probe in detecting the greater palatine artery or its greater branches non-invasively.

MATERIALS AND METHODS

The palatal mucosa of 108 participants (median age 34 years, 51 female) was systematically divided into transversal sectors, each aligning with the positions of the upper molars (M), premolars (P) and canine teeth (C), aiming to facilitate precise and consistent localization of the detected palatal blood vessel across different patients. Blood flow of the palatal blood vessels, presumably, was located by scanning the palatal vault bilaterally using an 8-MHz ultrasound probe linked to a transducer. The distance to the corresponding tooth was measured using a millimetre-scale periodontal probe.

RESULTS

Within the regions of M2 to P1, the ultrasound transducer gave a delimitable acoustic pulse signal in 80%-98% of all measurements. The measured median distances between the determined position of the artery and the corresponding teeth ranged from 13 to 15 mm, with smaller distances in the anterior region. In several sectors, the distance was significantly higher for men (C: p = .048; P1: p = .041, M1: p < .01; M2: p = .034).

CONCLUSIONS

Use of the Doppler ultrasound transducer might be a promising approach to non-invasively detect relevant palatine blood vessels preoperatively. It, therefore, might have the potential to reduce the risk of accidental injury during palatal surgery.

Differential molecular profiles and associated functionalities characterize connective tissue grafts obtained at different locations and depths in the human palate

The present study aimed to assess the molecular profiles of subepithelial connective tissue grafts (CTGs) obtained at different locations and depths in the human palate. Sixty-four CTGs belonging to anterior deep (AD), anterior superficial (AS), posterior deep (PD), and posterior superficial (PS) groups were subjected to RNA-Sequencing and their transcriptomes were analyzed computationally. Functional correlations characterizing the CTG groups were validated by cell biological experiments using primary human palatal fibroblasts (HPFs) extracted from the CTGs. A clearly more pronounced location-dependent than depth-dependent difference between the grafts, with a minimal number of genes (4) showing no dependence on the location, was revealed. Epithelial, endothelial, and monocytic cell migration was strongly (P < 0.001) potentiated by AD- and PS-HPFs. Moreover, significantly increased expression of genes encoding C-C and C-X-C motif chemokine ligands as well as significantly (P < 0.01) activated p38 signaling suggested immunomodulatory phenotype for AD- and PS-HPFs. Increased growth factor gene expression and significantly activated (P < 0.001) Erk and Akt signaling in HPFs originating from A-CTGs implied their involvement in cell survival, proliferation, and motility. Prominent collagen-rich expression profile contributing to high mechanical stability, increased osteogenesis-related gene expression, and strongly activated (P < 0.001) Smad1/5/8 signaling characterized HPFs originating from P-CTGs. The present data indicate that in humans, differences between palatal CTGs harvested from different locations and depths appear to be location- rather than depth-dependent. Our findings provide the basis for future personalization of the therapeutic strategy by selecting an optimal graft type depending on the clinical indications.

Three-dimensional mapping of the greater palatine artery location and physiology

OBJECTIVE

To develop a novel technique for localizing and reconstructing the greater palatine artery (GPA) using three-dimensional (3D) technology.

METHODS

A miniaturized intraoral ultrasound transducer was used to imaging landmarks including the GPA, gingival margin (GM), and palatal masticatory mucosa (PMM). A 5-mm-thick solid hydrogel couplant was integrated to replace traditional ultrasound gel and avoid bubbles when moving the transducer.

RESULTS

A panorama image provided the relative localization of landmarks including the GPA, PMM, and hard palate. Short- and long-axis imaging of GPA was performed in five subjects including 3D mapping of GPA branches and surrounding tissues in a volume of 10 mm × 8 mm × 10 mm. Full-mouth Doppler imaging was also demonstrated on both the dorsal and ventral tongue as well as buccal mucosa and sublingual region on two subjects.

CONCLUSIONS

This study can measure the vertical distance from the GM to the GPA and depth from PMM to GPA and visualize the GPA localization in a 3D manner, which is critical to evaluate the available volume of palatal donor tissues and avoid sectioning of GPA during surgical harvesting of the tissues. Finally, the transducer's small size facilitates full-mouth Doppler imaging with the potential to improve the assessment, diagnosis, and management of oral mucosa.

Determination of Palatal Soft Tissue Thickness and Safe Zone for Palatal Soft Tissue Harvest Using CBCT: A Retrospective Study

Aim

Our decision to conduct this study was motivated by the dearth of knowledge on geographical variations in the thickness of the palatal masticatory mucosa. The aim of the present study is to comprehensively analyze the palatal mucosal thickness and indicate the safety zone for palatal soft tissue harvesting using cone beam computed tomography (CBCT). Material and Methods. As this was a retrospective analysis of cases previously reported to the hospital, written consent was not acquired. The analysis was carried out on 30 CBCT images. Two examiners evaluated the images separately to avoid bias. Measurements were done from the midportion of the cementoenamel junction (CEJ) to the midpalatal suture in a horizontal line. Measurements were recorded from the maxillary canine, first premolar, second premolar, first molar, and second molar and were marked in axial and coronal sections at distances of 3, 6, and 9 mm from the CEJ. The relationship between palate soft tissue thickness in relation to each tooth, palatal vault angle, teeth, and the greater palatine grove was evaluated. Differences in the palatal mucosal thickness according to age, gender, and tooth site were evaluated. Categorical data were presented as frequencies and percentages. Numerical data are presented as mean and standard deviation values. They are explored for normality using Shapiro-Wilk's test. Data are normally distributed and are analyzed using one-way ANOVA followed by Tukey's post hoc test for independent variables and paired t-test for repeated measures. The significance level is set at p ≤ 0.05 for all tests. Statistical analysis is performed with R statistical analysis software version 4.1.3 for Windows.

Results

For sex and nationality, there was no significant association (p > 0.05), while for age, cases 35 years and older had significantly higher mucosal thickness than cases younger than 35 years old (p < 0.001). For all teeth, the association was statistically significant (p < 0.001). For the canine and first premolar, cases with deep angles had significantly higher mean values than those with moderate angles (p < 0.001). For other teeth, cases with deep angles had significantly higher mean values than other angles (p < 0.001).

Conclusion

Palatal mucosal thickness varied significantly from the canine to the second molar; the most appropriate site for graft harvesting is the canine to second premolar area which is 9-12 mm from the midpalatal suture aspect and is considered a safe zone for harvesting palatal graft.

Wound healing dynamics, morbidity, and complications of palatal soft-tissue harvesting

Palatal-tissue harvesting is a routinely performed procedure in periodontal and peri-implant plastic surgery. Over the years, several surgical approaches have been attempted with the aim of obtaining autogenous soft-tissue grafts while minimizing patient morbidity, which is considered the most common drawback of palatal harvesting. At the same time, treatment errors during the procedure may increase not only postoperative discomfort or pain but also the risk of developing other complications, such as injury to the greater palatine artery, prolonged bleeding, wound/flap sloughing, necrosis, infection, and inadequate graft size or quality. This chapter described treatment errors and complications of palatal harvesting techniques, together with approaches for reducing patient morbidity and accelerating donor site wound healing. The role of biologic agents, photobiomodulation therapy, local and systemic factors, and genes implicated in palatal wound healing are also discussed.

Midpalatal suture bone repair after miniscrew-assisted rapid palatal expansion in adults

Background

Midpalatal suture (MPS) repair in growing patients after RPE has been previously reported. However, differences between young and adult patients for timing and pattern of MPS repair after rapid maxillary expansion are expected. The aim of this study was to evaluate the midpalatal suture repair pattern after miniscrew-assisted rapid palatal expansion (MARPE) in adult patients.

Materials and methods

The study included 21 patients (six males, 15 females) successfully treated with MARPE with a mean initial age of 29.1 years of age (SD = 8.0; range = 20.1–45.1). MPS repair was evaluated using maxillary axial and coronal sections derived from CBCT exams taken 16 months after the expansion (SD = 5.9). Objective and subjective assessments of MPS repair were performed. Objective assessments were performed measuring MPS bone density at anterior, median and posterior region of hard palate. Pre-expansion and post-retention bone density changes were evaluated using paired t tests (p < 0.05). Midpalatal suture bone repair was scored 0 to 3 considering, respectively, the complete absence of bone repair in the MPS, the repair of less than 50% of the MPS, the repair of more than 50% of the MPS and the complete repair of the MPS. Intra- and interexaminer reliability evaluation were assessed using Kappa coefficient.

Results

The objective evaluation showed a significant higher bone density at the pre-expansion stage in all palatal regions. The reliability of the subjective method was adequate with intra- and interexaminer agreements varying from 0.807 to 0.904. Scores 1, 2 and 3 were found in 19.05%, 38.09% and 42.86% of the sample, respectively. The most common region demonstrating absence of bone repair was the middle third. The anterior third of the midpalatal suture was repaired in all patients.

Conclusions

A decreased bone density was observed after the retention period when compared to pre-expansion stage. Most adult patients demonstrated incomplete repair of the midpalatal suture 16 months after MARPE. However, adequate bone repair covering more than half of the hard palate extension was observed in 80.95% of the patients.

A 3D Digital Analysis of the Hard Palate Wound Healing after Free Gingival Graft Harvest: A Pilot Study in the Short Term

Purpose: Within this context, this pilot study aimed to evaluate the healing dynamics process of the hard palate after free gingival graft harvesting in the short term (3 months), utilizing digital imaging technology and tridimensional analysis software. Furthermore, assessing the results found to verify the existence of a relationship between gender or age with tissue loss. Materials and Methods: For connective-tissue harvesting, fifteen patients with gingival recessions type (RT) 1 and RT2 were selected. On the surgery day (before the procedure) and after three months, palatal impressions were taken in all patients, and cast models were done for posterior model scanning. The following variables were analyzed: mean thickness alterations (x¯ TA), maximum thickness loss (MTL), mean maximum thickness loss (x¯ MTL), and volume alterations (VA). A descriptive and bivariate analysis of the data was done. The data were submitted for statistical evaluation and were significant if p < 0.05. Results: Fifteen patients were analyzed, 11 females (73.3%) and four males (26.7%). The patients’ average age was 28 ± 8.52 years (ranging between 16 and 48 years old). The palatal wound region’s mean thickness and volume changes were −0.26 mm (±0.31) and 46.99 mm3 (±47.47 mm3) at three months. There was no statistically significant result correlating age/gender with any variable evaluated. Conclusions: Connective tissue graft harvesting promoted changes with a standard volume and thickness loss of palatal soft tissue. A 3D digital evaluation was a non-invasive method with a reproducible technique for measuring thickness or volume after connective tissue is collected. There was no relationship between age/gender and any variables analyzed.

Accuracy evaluation of 3D-printed noninvasive adhesive marker for dynamic navigation implant surgery in a maxillary edentulous model: An in vitro study

Dynamic computer-aided implant surgery (DCAIS) can improve dental implantation accuracy and reduce surgical risks. In the registration procedure of DCAIS, the type and the number of registration markers significantly impact the accuracy of DCAIS. One problem of DCAIS in clinical application is that only invasive screw markers can be used for implantation in edentulous patients. It could cause additional trauma, scar formation and usually increase patient discomfort. In this experiment, a personalized 3D-printed edentulous maxillary model was used for simulating clinical situations, and a 3D-printed noninvasive adhesive marker (3D-PNAM) was designed to figure out the above problem. In this research, six target screws were implanted into the model's maxillary alveolar ridge as targets for accuracy analysis. This study used target registration error (TRE) as an index to evaluate the accuracy of invasive screw makers and noninvasive adhesive markers. Results showed that 3D-PNAMs had the same accuracy as screw markers, and placing at least six registration markers in the maxilla was needed for good registration accuracy. The registration markers should be further improved and designed according to application areas' clinical needs and anatomical characteristics in future clinical studies.

Palatal mucosa thickness and palatal neurovascular bundle position evaluation by cone-beam computed tomography-retrospective study on relationships with palatal vault anatomy

Background

Measuring the thickness of the palatal mucosa at the planning of the surgical procedure is an important step in order to obtain the maximum width and thickness of the graft from the appropriate area. The aim of this study is to determine whether there is a relationship between palatal angle (PA) or palatal depth (PD) and palatal mucosa thickness (PMT) or palatal neurovascular bundle distance (PNBD).

Methods

PMT, PNBD, PD and PA were measured on cone-beam computed tomography (CBCT) images of maxillary posterior region of 200 male and 200 female patients. The mean of all parameters according to gender was compared and the significance of the difference detected between groups was evaluated. Potential relationship between PMT or PNBD and PA or PD was also evaluated.

Results

In females, the palatal mucosa was significantly thinner at all tooth regions (p < 0.005), and PNBD was lower only at the level of the second molar (p < 0.001). In addition, it was found that there was a significant inverse correlation between the palatal depth value and the palatal mucosal thickness, and palatal depth was correlated with the palatal neurovascular bundle distance (p ≤ 0.001).

Discussion

Consistent with previous studies, it was observed that the thickest mucosa in the palatal region was located in the region of the premolar teeth, and women had thinner palatal mucosa. In addition, in patients with a deeper palate vault, the palatal mucosa was thinner, but the palatal neurovascular bundle was more distant from the cemento-enamel junction.

Targeted Endodontic Microsurgery: Implications of the Greater Palatine Artery

INTRODUCTION

Targeted Endodontic Microsurgery (TEMS) combines trephine burs and 3D-printed guides to make flapless maxillary palatal root-end surgery possible. This study assessed the location of the greater palatine artery (GPA), the relationship of the GPA to maxillary molar root ends, and the feasibility of flapless palatal-approach TEMS.

METHODS

Three endodontists analyzed 250 cone-beam computed tomographic images of maxillary molars for (1) transition morphology between the hard palate and the alveolar process adjacent to first and second molars as an indication of the most likely location of the GPA, (2) the superior-inferior relationship between the GPA and root ends, and (3) the feasibility of palatal-approach TEMS.

RESULTS

Palatal transition morphology included 20% Spine, 72% Bridge, and 8% Smooth. GPA position as related to palatal root ends was classified as 34% superior, 40% adjacent, and 21% inferior. Five percent of classifications were undefined. TEMS was deemed feasible for 47% of maxillary first molars and 52% of second molars, and was significantly more feasible with GPAs superior to palatal root ends. Reasons for infeasibility included GPA proximity and unfavorable resection angle or level. Maxillary first molar palatal roots were 11.13 ± 2.68 mm from the greater palatine foramen (GPF) and 2.37 ± 1.46 mm from the GPA. Second molar palatal roots were 4.94 ± 2.55 mm from the GPF and 2.53 ± 1.77 mm from the GPA.

CONCLUSIONS

Palatal transition morphology and GPA position adjacent to maxillary molars, as manifested in cone-beam computed tomographic coronal views, suggested maxillary palatal root TEMS could be accomplished with a 2-mm safety margin in 47% of first molars and 52% of second molars. Historical paradigms that do not consider flapless palatal surgical approaches may need to be revised.

Accuracy of cone beam computed tomography in evaluation of palatal mucosa thickness

AIM

The purpose of this study was to investigate the accuracy of the measurement of palatal mucosa thickness using cone beam computed tomography (CBCT) and to create a conversion formula to evaluate palatal mucosa thickness more accurately. We then evaluated the palatal mucosa thickness in a Japanese population using CBCT and the conversion formula.

MATERIALS AND METHODS

We evaluated palatal mucosa thickness in 10 healthy subjects at 15 sites using CBCT, digital impression, and K file. Multiple regression analysis was performed to create a conversion formula to measure thickness accurately. We then obtained CBCT data from 174 patients retrospectively, applied the conversion formula, and evaluated palatal mucosa thickness.

RESULTS

Sites of measurement affected measurement error. Measurement using CBCT was 0.34 ± 0.04 mm smaller than actual measurement; therefore, a conversion formula was created. Male, age ≥60 years, and probing pocket depth ≥4 mm had significant and positive associations with palatal mucosa thickness; however, no association was observed between bleeding on probing and palatal mucosa thickness.

CONCLUSION

CBCT is useful for the noninvasive and accurate measurement of palatal mucosa thickness.

What Is the Safety Zone for Palatal Soft Tissue Graft Harvesting Based on the Locations of the Greater Palatine Artery and Foramen? A Systematic Review

PURPOSE

Palatal soft tissue graft harvesting is a common procedure in periodontal and implant dentistry. However, most of the complications after this procedure are associated with the underestimation of anatomic structures, such as the greater palatine artery (GPA). Therefore, the aim of this study was to provide guidelines for a safety zone for palatal harvesting.

MATERIALS AND METHODS

A systematic search was conducted to identify cadaveric and computed tomography (CT) or cone beam CT studies assessing the location of the greater palatine foramen (GPF) and the path of the GPA in relation to the maxillary teeth. The effect of age, gender, and cadaveric and CT or cone beam CT studies on the location of the GPF and on the course of the GPA also was assessed.

RESULTS

This systematic review included 26 studies, investigating 5,768 hemipalates. The most common location of the GPF was in the midpalatal aspect of the third molar (57.08%). As it traverses the palate anteriorly, the distance from the GPA to the maxillary teeth gradually decreases, except in the second premolar region, where it has the tendency to increase (13.8 ± 2.1 mm). The least distance from the GPA to the teeth was found in the canine area (9.9 ± 2.9 mm), whereas the greatest distance was in the second molar region (13.9 ± 1 mm). A safety zone for palatal harvesting was proposed based on the anatomic findings.

CONCLUSIONS

This study provides guidelines for identifying the position of the GPF and defines a safety zone for harvesting a free gingival graft or connective tissue graft, minimizing the risk of GPA injury.

Endoscopic Endonasal Landmarks to the Greater Palatine Canal: A Radiographic Study

Background  The palatine neurovascular bundle is at risk during endoscopic surgery. Injury may result in significant blood loss and anesthesia of the ipsilateral hard palate. Nonetheless, its endoscopic anatomy has not been described previously. This article strives to establish landmarks to identify the greater palatine canal; thus, avoiding injury to its contents. Methodology  This study comprised 50 deidentified computed tomographic angiograms using landmarks that are immediately visible during endoscopic medial maxillectomy to calculate: the angle of the greater palatine canal to the vertical, the distance from the anteroinferior aspect of the greater palatine canal to the orifice of the nasolacrimal duct, the distance from the anteroinferior aspect of the greater palatine canal to the posterolateral free edge of the hard palate, and the distance from the anterior aspect of the greater palatine canal as it enters the hard palate to the posterior wall of the maxillary sinus. Results  The mean angle of the greater palatine canal to the vertical was 23.01 degrees. The mean distance from the anteroinferior aspect of the greater palatine canal to the nasolacrimal duct was 31.52 mm. The mean distance from the anterior aspect of the greater palatine canal to the posterolateral free edge of the hard palate was 7.71 mm and the mean distance from the anterior aspect of the greater palatine canal to the posterior wall of the maxillary sinus was 7.07 mm. Conclusion  Accessible anatomical landmarks help ascertain the location of the greater palatine canal intraoperatively; thus, avoiding injury to its contents.

Randomized controlled clinical study evaluating effectiveness and safety of a volume-stable collagen matrix compared to autogenous connective tissue grafts for soft tissue augmentation at implant sites

AIM

To test whether or not the use of a collagen matrix (VCMX) results in short-term soft tissue volume increase at implant sites non-inferior to an autogenous subepithelial connective tissue graft (SCTG), and to evaluate safety and tissue integration of VCMX and SCTG.

METHODS

In 20 patients with a volume deficiency at single-tooth implant sites, soft tissue volume augmentation was performed randomly allocating VCMX or SCTG. Soft tissue thickness, patient-reported outcome measures (PROMs), and safety were assessed up to 90 days (FU-90). At FU-90 (abutment connection), tissue samples were obtained for histological analysis. Descriptive analysis was computed for both groups. Non-parametric tests were applied to test non-inferiority for the gain in soft tissue thickness at the occlusal site.

RESULTS

Median soft tissue thickness increased between BL and FU-90 by 1.8 mm (Q1:0.5; Q3:2.0) (VCMX) (p = 0.018) and 0.5 mm (-1.0; 2.0) (SCTG) (p = 0.395) (occlusal) and by 1.0 mm (0.5; 2.0) (VCMX) (p = 0.074) and 1.5 mm (-2.0; 2.0) (SCTG) (p = 0.563) (buccal). Non-inferiority with a non-inferiority margin of 1 mm could be demonstrated (p = 0.020); the difference between the two group medians (1.3 mm) for occlusal sites indicated no relevant, but not significant superiority of VCMX versus SCTG (primary endpoint). Pain medication consumption and pain perceived were non-significantly higher in group SCTG up to day 3. Median physical pain (OHIP-14) at day 7 was 100% higher for SCTG than for VCMX. The histological analysis revealed well-integrated grafts.

CONCLUSIONS

Soft tissue augmentation at implant sites resulted in a similar or higher soft tissue volume increase after 90 days for VCMX versus SCTG. PROMs did not reveal relevant differences between the two groups.

Evaluation of the neurovascular bundle position at the palate with cone beam computed tomography: an observational study

BACKGROUND

The aim of this study was to investigate the neurovascular bundle (NVB) position with cone-beam computerized tomography (CBCT).

METHODS

CBCT images of 345 patients were evaluated. The distance from the neurovascular bundle to the cemento-enamel junction (CEJ) was measured (DNB). The distance from mid-palatal suture to the alveolar crest was used to determine the palatal depth. Palatal junction angle (PA) was measured using the junction angle between the hard palate and alveolar crest. The relationships between the DNB and the palatal depth and between these two parameters and the PA were evaluated. Student's t-test was used to analyze the differences in DNB related to gender, and the correlation between the DNB while Pearson correlation analysis was used to determine the correlation between the DNB and age (p = 0.05). The relationship between the DNB and the palatal depth, and the relationship between these two parameters and the PA were also evaluated using Pearson correlation analysis.

RESULTS

Except at the canine and first premolar areas the DNB was positively correlated with the palatal depth. No significant relationship between the PA and DNB or with PVD was observed. The highest DNB was 14 mm at the first molar, and the lowest was 10.8 mm at the canine.

CONCLUSIONS

Care is needed while rotating flap and harvesting the subepithelial connective tissue graft at the canine area because the neurovascular bundle passes approximately 11 mm apically to CEJ at the canine region.

Anatomical preconditions for the palatal sinus floor augmentation—A three-dimensional feasibility study

OBJECTIVE

The aim of this study was to evaluate the anatomical feasibility of palatal sinus floor augmentation.

MATERIAL AND METHODS

In 100 men and 100 women, both sinuses were analyzed using computed tomography. The patients were divided into four anatomical groups according to the remaining alveolar bone height: group 1 (0 ≤ × < 4), group 2 (4 ≤ × < 8), group 3 (8 ≤ × < 12), and group 4 (≥12).

RESULTS

The 400 maxillary sinuses consisted of 23.5% (n = 94) group 1, 42.75% (n = 171) group 2, 23.5% (n = 98) group 3, and 9.25% (n = 37) group 4 sinuses. Optimal anatomical preconditions for palatal sinus floor augmentations (i.e., ≥5 mm height and <5 mm thickness of the window lid) were found in 93.6% of group 1 sinuses, 73.7% of group 2 sinuses, 23.5% of group 3 sinuses, and 5.4% of group 4 sinuses.

CONCLUSION

The palatal approach is feasible in 93.6% of patients with remnant alveolar height of up to 4 mm. Limitations are alveolar heights of ≤5 mm as well as great palatal thickness and thus limited dimensions for a possible palatal window.