Quantitation of Mandibular Symphysis Bone as Source of Bone Grafting: Description in Class I and Class III Skeletal Conditions

Comparison of rhBMP-2 in Combination with Different Biomaterials for Regeneration in Rat Calvaria Critical-Size Defects

Regeneration of critical bone defects requires the use of biomaterials. The incorporation of osteoinductive agents, such as bone morphogenetic proteins (BMPs), improves bone formation. This study aimed to compare the efficacy of rhBMP-2 in combination with different materials for bone regeneration in critical-sized rat calvarial defects. This was an experimental animal study using 30 rats. In each rat, two 5-mm critical-size defects were made in the calvaria (60 bone defects in total) using a trephine. All rats were randomized to one of the six groups: control (C), autograft + rhBMP-2 (A), absorbable collagen sponge + rhBMP-2 (ACS), β-tricalcium phosphate + rhBMP-2 (B-TCP), bovine xenograft + rhBMP-2 (B), and hydroxyapatite + rhBMP-2 (HA). The outcome was assessed after 4 and 8 weeks using histological description and the histological bone healing scale. Statistical analysis was performed using the Kruskal-Wallis and Mann–Whitney U tests, with a p-value set at 0.05. The average bone healing scores per group were as follows: C group, 12.5; A group, 26.5; ACS group, 18.8; B-TCP group, 26.2; HA group, 20.9; and B group, 20.9. The C group showed a significant difference between weeks 4 and 8 (p = 0.032). Among the 4-week groups, the C group showed a significant difference compared to A (p = 0.001), ACS (p = 0.017), and B-TCP (p = 0.005) groups. The 8-week experimental group did not show any significant differences between the groups. The 5-mm critical size defect in rat calvaria requires the use of bone biomaterials to heal at 4 and 8 weeks. rhBMP-2, as applied in this study, showed no difference in new bone formation when combined with bovine, B-TCP, or HA biomaterials.

Anatomical Variations of the Mandibular Symphysis in a Normal Occlusion Population Using Cone-Beam Computed Tomography

This study aimed to assess the anatomical variations of the mandibular symphysis in a normal occlusion population using cone-beam computed tomography (CBCT). This retrospective cross-sectional study evaluated 200 CBCT scans of patients aged ≥17 with class I occlusion, 1-3 mm overbite and overjet, and <3 mm crowding. The CBCT scans were obtained with NewTom 3G scanner with the exposure settings of 110 kVp, 1.2 mA, 5.4 s time, and six-inch field of view and saved in NNT Viewer. The anterior loop length, labial bone thickness, mandibular bone height at the symphysis, and cortical bone thickness at the right and left canine teeth and central and lateral incisors were measured and compared between males and females and different age groups using one-way ANOVA. The intra- and inter-observer agreements for all landmarks were ICC >0.9 (excellent). The mean length of the anterior loop in females was significantly greater than that in males (P=0.02). Different age groups had significant differences in cortical bone width at the site of the left canine (P=0.03) and vertical bone height at the site of the right central incisor (P=0.05). The majority of parameters related to the mandibular symphysis were greater in normal occlusion males than females. Preoperative CBCT assessment of the mandibular symphysis can greatly help in diagnosis and treatment planning as well as bone harvesting from this area.

Preclinical and Clinical Applications of Biomaterials in the Enhancement of Wound Healing in Oral Surgery: An Overview of the Available Reviews

Oral surgery has undergone dramatic developments in recent years due to the use of biomaterials. The aim of the present review is to provide a general overview of the current biomaterials used in oral surgery and to comprehensively outline their impact on post-operative wound healing. A search in Medline was performed, including hand searching. Combinations of searching terms and several criteria were applied for study identification, selection, and inclusion. The literature was searched for reviews published up to July 2020. Reviews evaluating the clinical and histological effects of biomaterials on post-operative wound healing in oral surgical procedures were included. Review selection was performed by two independent reviewers. Disagreements were resolved by a third reviewer, and 41 reviews were included in the final selection. The selected papers covered a wide range of biomaterials such as stem cells, bone grafts, and growth factors. Bioengineering and biomaterials development represent one of the most promising perspectives for the future of oral surgery. In particular, stem cells and growth factors are polarizing the focus of this ever-evolving field, continuously improving standard surgical techniques, and granting access to new approaches.

Comparison of anterior mandibular alveolar thickness and height in young adults with different sagittal and vertical skeletal relationships: A CBCT Study

OBJECTIVE

Alveolar bone surrounding mandibular incisors dictates the range of buccolingual inclination that can be achieved with treatment. The objective of this study was to evaluate the mandibular anterior alveolar thickness and height in individuals with different sagittal and vertical skeletal relationships.

MATERIALS AND METHODS

Cone beam computed tomography scans of 53 individuals (22 males and 31 females; mean age 21.19±3.7 years) were classified into 3 groups according to the sagittal skeletal relationship (class I, class II, and class III) and the vertical growth pattern (hyperdivergent, normodivergent, and hypodivergent). The alveolar thickness and height of both mandibular central incisors were measured. Group comparisons were performed with analysis of variance and post hoc Scheffé tests. Multiple linear regression was applied to evaluate the influence of all variables on the alveolar conditions.

RESULTS

Alveolar thickness and height showed no significant differences among the class I, II and III groups (6 and 7mm regardless of the sagittal group, P>0.05). The middle and lower alveolar thicknesses were significantly smaller in hyperdivergent (5.76mm and 6.34mm) and normodivergent (6.29mm and 7.40mm) than hypodivergent individuals (6.63mm and 8.27mm respectively). The lingual alveolar height was smaller in hyperdivergent (6.04mm) than hypodivergent individuals (7.93mm) (P=0.029, 95%CI: 0.15-3.63) and the lingual bone height was smaller in hypodivergent (3.24mm) than hyperdivergent individuals (5.06mm) (P=0.029, 95%CI: 0.15-3.48). Multiple linear regression indicated a significant influence of the root length on the alveolar thickness and height.

CONCLUSIONS

The sagittal skeletal relationship showed no influence on the alveolar thickness or height, even if dental compensation was present. Hyperdivergent individuals showed smaller alveolar thicknesses and heights than hypodivergent individuals.

Bone grafting materials in dentoalveolar reconstruction: A comprehensive review

Bone deficits of the jaws are often attributed to accidents, surgical removal of benign lesions or malignant neoplasms, congenital abnormalities, periodontal inflammation, tooth abscess or extraction and finally jaw atrophy due to advanced age or general disease. These bone defects require rehabilitation for a variety of reasons, e.g. maintaining the normal anatomic outline, eliminating empty space, aesthetic restoration and placing dental implants. Today, several techniques have been developed to eliminate these bone deformities including bone grafting, guided bone regeneration, distraction osteogenesis, use of growth factors and stem cells. Bone grafts consist of materials of natural or synthetic origin, implanted into the bone defect site, documented to possess bone healing properties. Currently, a variety of bone restorative materials with different characteristics are available, possesing different properties. Despite years of effort the 'perfect' bone reconstruction material has not yet been developed, a further effort is required to make this objective feasible. The aim of this article is to provide a contemporary and comprehensive overview of the grafting materials that can be applied in dentoalveolar reconstruction, discussing their properties, advantages and disadvantages, enlightening the present and the future perspectives in the field of bone regeneration.