The "HAT-TRICK" technique: A modification of soft tissue grafting using volume stable collagen matrix and cross-linked hyaluronic acid. Part A: The pontic site.

Vertical soft tissue augmentation between implants can be clinically challenging and burdensome for patients when employing conventional techniques. Recently, with the introduction of xenogenic collagen matrices, the principle of single-site surgery has become more common. However, some issues persist regarding graft stability and tissue integration. In the present technical note, the authors introduce the "HAT-TRICK" technique to address these observed difficulties. As the name suggests, this technique is believed to provide improved stability, volumetric gain, and histological integration of the implanted matrix by shaping it appropriately resembling a hat over the crest with apical bevels, stabilized with fixation pins and infused with cross-linked hyaluronic acid (xHya). A two-month observation of a bi-maxillary case is presented with detailed description of the technique and digitalized comparison methods for an easier explanation of the introduced technique.

Three-dimensional radiographic assessment of immediate implant placement in the posterior mandible: A novel parameter-based classification.

OBJECTIVES: To assess the implant position (IP), the interradicular septum width (ISW) and radiographic bone to implant contact (BIC), when simulating an immediate implant placement in first and second mandibular molars. STUDY DESIGN: 75 patients (150 sites) were studied using cone beam computed tomography scans (CBCT) and computer aided design software. Implants were placed in a prosthetically driven position; subsequently, IP and BIC were digitally calculated. Linear ISW was also analyzed at 2, 4 and 6mm apically to the highest septal bony peak. Multiple linear regressions were performed to assess relationships between BIC and the different predictive variables. Additionally, the receiver operating characteristics (ROC) curve was used to create a model for BIC based on the ISW at 2mm. RESULTS: BIC in implants replacing first molars was the highest at the septal (S) position when compared to those in septal-mesial (S-M) position (p-value 0.001). As for the second molar, the highest percentage of BIC was recorded at the septal (S) position, followed by those in S-M and mesial (M) positions (p<0.001). CONCLUSION: According to the proposed classification, clinician must consider the ISW and IP when placing immediate implant in the first and second mandibular molar sites. When tackling first molars, S position is predominant, while S-M position is the most common in the second molars. ISW at 2mm should be at least respectively 2mm and 2.5mm at the first and second molar sites to achieve 50% of BIC.

Three-dimensional radiographic assessment of the mandibular retromolar donor site in different vertical facial growth types.

PURPOSE: To assess volumetrically, the impact of vertical facial growth types (VGFT) on the retromolar area as a bone donor site MATERIAL AND METHODS: 60 cone beam computed tomography (CBCT) scans of adult individuals were classified in three groups according to their SN-GoGn angle: hypodivergent group (hG) (33.33%), normodivergent group (NG) (30%) and hyperdivergent group (HG) (36.67%). Total harvestable bone volume and surface (TBV and TBS respectively), total cortical and cancellous bone volume (TCBV and TcBV respectively) and the percentage of cortical and cancellous bone volume (CBV and cBV respectively) were evaluated. RESULTS: The whole sample showed a mean TBV of 1220.99±448.81mm³ and a mean TBS of 940.29±259.93mm². Statistically significant differences were found between the different outcome variables and the vertical growth patterns (p<0.001). TBS differs for the different vertical growth patterns with the highest mean of TBS observed in the hG group. TBV also significantly differs between the different vertical growth patterns (p<0.001) with the highest mean observed for the hG individuals. Significant differences in percentages of cBV and CBV were present between the hyper-divergent groups and the other groups (p<0.001) with the hyper-divergent group having the lowest percentage of CBV and the highest percentage of cBV. CONCLUSION: hypodivergent individuals tend to have thicker bone blocks that can be used in onlay technique while thinner bone blocks harvested from hyperdivergent and normodivergent individuals can be used in three-dimensional grafting approach.

Clinical and radiographic assessment of cross-linked hyaluronic acid addition in demineralized bovine bone based alveolar ridge preservation: A human randomized split-mouth pilot study.

PURPOSE: To investigate clinically and radiographically at 4 months post-operatively the outcomes of mixing demineralized bovine bone material (DBBM) with cross-linked hyaluronic acid in alveolar ridge preservation. MATERIAL AND METHODS: Seven patients presenting bilateral hopeless teeth (14 teeth) were enrolled in the study, the test site contained demineralized bovine bone material (DBBM) mixed with cross-linked hyaluronic acid (xHyA) while the control site contained only DBBM. 4 months post-operatively prior to implant placement a Cone beam computed tomography (CBCT) scan was recorded and compared to the initial scan to assess the volumetric and linear bone resorption that occurred in both sites. Clinically, sites that needed further bone grafting at the implant placement stage were recorded. Differences in volumetric and linear bone resorption between both groups were assessed using Wilcoxon signed rank test. McNemar test was also used to evaluate difference in bone grafting need between both groups. RESULTS: All sites healed uneventfully, volumetric and linear resorption differences between the baseline and 4 months post-operatively were obtained for each site. The mean volumetric and linear bone resorption were respectively 36.56 ± 1.69%, 1.42 ± 0.16 mm in the controls sites and 26.96 ± 1.83%; 0.73 ± 0.052 mm in the tests sites. The values were significantly higher among controls sites (P=0.018). No significant differences were observed in the need for bone grafting between both groups. CONCLUSION: Cross-linked hyaluronic acid (xHyA) appears to limit the post-extractional alveolar bone resorption when mixed with DBBM.

Assessment of infrazygomatic crest dimensions in different vertical facial growth types for miniscrew insertion: A cone-beam computed tomography study.

INTRODUCTION: This study aimed to assess the depth and height of the infrazygomatic crest (IZC) located in the posterior maxilla at the junction with the zygomatic process in patients with different vertical facial growth types as a potential miniscrew insertion site. METHODS: The sample consisted of cone-beam computed tomography scans of 117 patients (42 males and 75 females), with a mean age of 22.9 ± 2.7. The population was divided into 3 groups according to the measured SN-GoGn angle: Decreased facial proportions (n = 28), average facial proportions (n = 62), and increased facial proportions (n = 27). Bone depth was assessed at 5 levels: apex, 1, 2, 3, and 4 mm vertically from the apex. The measurements were performed on the mesiobuccal and distobuccal roots of the first molar and the mesiobuccal root of the second molar. Repeated-measure analysis of variance followed by univariates analyses and Bonferroni multiple comparisons were performed to compare the mean bone thickness between groups. The IZC height was assessed through a vertical line ranging from the furcation of the maxillary first molar to the sinus floor. Analysis of variance followed by Tukey (honestly significant difference) post-hoc tests was used to compare the mean height between groups. RESULTS: Mean bone depth between the 3 groups were significantly different at the mesiobuccal root region of the first molar at all the measured levels. It was smaller for average, intermediate for decreased, and elevated for increased facial proportions. No statistical difference was shown at the distobuccal root of the first molar except for the apex level and the mesiobuccal root of the second molar except for the apex and 4 mm levels. The mean bone height was significantly different between subjects with increased facial proportions and the 2 other groups. CONCLUSIONS: Subjects with increased facial proportions tend to present a longer and deeper IZC followed by decreased facial proportions, then average facial proportions.

Assessment of lower third molar space: A comparative radiographic study.

OBJECTIVE: The aim of this study was to assess lower third molar space using four different radiographic reconstructed Cone Beam Computed Tomography (CBCT) images: orthopantomogram, lateral cephalogram, multiplanar CBCT and a newly introduced three-dimensional (3D) simulation technique. METHODS: The CBCT scans of 32 individuals (20.97 ± 2.152 years) with a total of 50 lower third molars were collected and analyzed. The ratio between the necessary space and available space for lower third molars was calculated on each radiographic reconstructed image. Repeated-measure analysis of variance followed by multiple comparison tests were used. RESULTS: The mean ratio was significantly smaller with cephalograms (0.611 ± 0.263), followed respectively by orthopantomograms (0.756 ± 0.221), multiplanar CBCT (0.789 ± 0.191) and 3D simulation technique (0.807 ± 0.193) (p < 0.001). The lowest mean difference was recorded between multiplanar CBCT and 3D simulation technique (0.017). Intraclass correlation coefficient was strong (>0.90) for all techniques except cephalograms. CONCLUSIONS: The assessment of the lower third molar space differs according to the adopted imaging technique. Three-dimensional simulation technique is a useful novel technology that allows an exploration of the crown in many different dimensions and orientations, giving more predictable results than the conventional methods.

Oral manifestations associated with inherited hyperhomocysteinemia: A first case description.

Hyperhomocysteinemia is a rare disease caused by nutritional deficiencies or genetic impairment of cysteine metabolism. To date, no oral manifestations of hyperhomocysteinemia have been described in humans. Therefore, to our knowledge, the present case report is the first description of a hyperhomocysteinemic patient showing oral tissue alterations leading to both early tooth loss and failed implant osseointegration. The patient presented with a methylenetetrahydrofolate reductase gene mutation (677T polymorphism) leading to mild hyperhomocysteinemia. The radiologic analysis showed hyperdense lesions scattered in the maxillae. The histologic observations indicated alterations in both collagen and elastic networks in the gingiva and dermis. Interestingly, the presence of ectopic mineralized inclusions was noted in both periodontal ligament and gingiva. Strong osteoclastic activity was associated with abnormal calcification of trabecular spaces. Uneven oral tissue remodeling due to high tissue levels of homocysteine could explain the pathologic manifestations observed in this case.