Assessment of jaw bone mineral density, resorption rates, and oral health in patients with severe hemophilia: a case-control study.

OBJECTIVE: Knowledge about oral hygiene, gingival bleeding, mineral density, and resorption of jaw bones in patients with hemophilia is limited. We evaluated the periodontal and bone status in such patients.  Material and methods: Forty-eight patients with severe type A/B hemophilia and 49 age- and sex-matched controls were included. Assessments included simplified oral hygiene index (OHI-S), calculus index, debris index, gingival index (GI), gingival bleeding time index (GBTI), and decayed, missing, and filled teeth index (DMFTI). Bone resorption was evaluated using panoramic mandibular index (PMI), mental index (MI), and alveolar crest ratio (ACR). Mineral density in the condyle, angulus, and premolar areas was assessed using fractal analysis, with fractal dimensions denoted as condyle fractal dimension (CFD) for the condyle, angulus fractal dimension (AFD) for angulus, and premolar fractal dimension (PFD) for premolar region. RESULTS: The mean scores were DMFTI = 11.77, OHI-S = 2.44, PMI = 0.268, MI = 5.822, GI = 3.02, GBTI = 2.64, ACR = 2.06, CFD = 1.31, AFD = 1.31, and PFD = 1.17 in the hemophilia group and DMFTI = 11.449, PMI = 0.494, MI = 7.43, GI = 0.67, GBTI = 0.98, OHI-S = 1.45, ACR = 2.87, CFD = 1.35, AFD = 1.35, and PDF = 1.23 in the control group. Differences were significant for all parameters (p < 0.005) except for the DMFTI index.  Conclusions: Because of poor oral hygiene, high bone resorption, and low bone mineral density in these patients, clinicians should consider potential bone changes when planning to treat these patients.

Comparison of implant placement at crestal and subcrestal levels in aesthetic zone: A finite element analysis.

PURPOSE: The success rate of the implant treatment, including aesthetics and long-term survival, relies heavily on preserving crestal peri-implant bone, as it determines the stability and long-term outcomes. This study aimed to demonstrate the stress differences in the crestal bone resulting from dental implant placement at various depths relative to the crestal bone level using finite element analysis. MATERIALS AND METHODS: Three study models were prepared for implant placement at the crestal bone level (CL), 1 mm depth (SL-1), and 2 mm depth (SL-2). Implants were placed in the maxillary central incisor region of each model, and 100 N vertical and oblique forces were applied. The von Mises, maximum principal (tensile), and minimum principal (compressive) stresses were evaluated. RESULTS: The CL model exhibited the highest stresses on the implant, abutment, and abutment screws under vertical and oblique forces. For maximum principal stress in the crestal bone under vertical force, the SL-2, SL-1, and CL models recorded values of 6.56, 6.26, and 5.77 MPa, respectively. Under oblique forces, stress values for SL-1, SL-2, and CL were 25.3, 24.91, and 23.76 MPa, respectively. The CL model consistently exhibited the lowest crestal bone stress at all loads and the highest stress values on the implant and its components. Moreover, considering the yield strengths of the materials, no mechanical or physiological complications were noted. CONCLUSIONS: Placing the implant at the crestal level or subcrestally beyond the cortical layer could potentially reduce stress and minimize crestal bone loss. However, further studies are warranted for confirmation.

Assessment of different treatment alternatives for patients with total maxillectomy.

PURPOSE: To assess the biomechanical advantages of combining zygoma and partial subperiosteal implants for maxillary reconstruction in severely atrophic maxillae, offering potential solutions to the challenges posed by traditional reconstruction methods. MATERIAL AND METHODS: A finite element analysis used a craniofacial model simulating a totally resected maxilla. Four treatment scenarios (SCs) were evaluated: SC-1, the quad zygoma approach; SC-2, two zygoma implants (ZIs) and a one-piece subperiosteal implant (SI); SC-3, two ZI and a two-piece SI; and SC-4, four ZI and a one-piece SI. Stress distributions on bone, implants, abutments, and metal frameworks were compared under occlusal forces. RESULTS: For the simulated bone regions under vertical and oblique forces, SC-4 values were higher than SC-1, while SC-2 and SC-3 values were comparable for pmax and pmin. In addition, SC-2 and SC-3 values were lower than those of SC-1 and SC-4. The most balanced von Mises stress values on the ZIsand were observed in SC-3 under vertical and oblique forces. Furthermore, lower von Mises stress values on the abutments were seen in SC-3 under oblique and vertical forces. Although the lower von Mises stress values on the metal frameworks at the lateral incisor and first premolar side were seen in SC-3, lower von Mises values were observed in SC-4 in the first molar region. CONCLUSIONS: Overall, this study suggests that combining zygoma and partial subperiosteal implants may be a promising approach for reconstructing severely atrophic maxillae. These implants may offer improved biomechanical properties compared to ZIs alone.

Impact of bone levels on stress distribution around all-on-four concept: A 3-D finite element analysis.

This study aimed to investigate the impact of implant placement levels within the bone on stress distribution in the context of the All-on-Four concept. In this Finite Element Analysis(FEA), two 4.1 mm x 10 mm implants were axially placed in the anterior region of the jawbone, while two 4.1 mm x 14 mm implants were tilted at 30 ° in the posterior region following the all-on-four concept. In the EC scenario, all implants were inserted at the equicrestal level. In other scenarios, implants were positioned at 1 mm and 2 mm subcrestal levels (SC1, SC2). In all groups, the prosthesis was designed to replicate a group-function occlusion. A total load of 450 N was applied to the prosthesis. Upon deeper implant placement below the crest level, a trend of decreasing Von Mises stresses was observed in both implants and implant fragments. The highest Pmax value in the bone was recorded in SC-2, characterized by the absence of cortical bone support, with values of 3.16 N/mm2 in the anterior region and 1.55 N/mm2 in the posterior region. Conversely, the lowest Pmax values were noted in SC-1 for the anterior implant (2.67 N/mm2) and the EC for the posterior implant (0.87 N/mm2). Implant placements devoid of cortical bone support result in stress transmission from the implant and its components to the peri-implant bone. Optimal stress minimization is achieved by placing anterior axial angle implants deeper than the crest level while retaining cortical bone support and positioning posterior tilted implants at the crest level.

Assessment of the approach to managing medical emergencies during dental procedures.

OBJECTIVE: This study aims to investigate the knowledge of dental interns and post-graduated doctors regarding dental emergencies and their occurrence in the clinic and examine the doctors' ability to intervene in these emergencies. METHODS: Note that, 150 dental interns and 101 post-graduated doctors were surveyed with sixteen questions regarding their knowledge and experience with syncope, orthostatic hypotension, myocardial infarction, angina pectoris, asthma, and anaphylactic shock. Also, post-graduate doctors answered nine additional questions about their emergency response capabilities. RESULTS: This study found that interns and doctors exhibited similar knowledge about emergencies. Nonetheless, the count of dental interns encountering emergencies is relatively limited. Syncope was the most frequently encountered condition (61.8%). Doctors' increase in years of experience correlated positively with a higher rate of intervention in epilepsy, orthostatic hypotension, and anaphylactic shock (p = 0.001, 0.024, and 0.02, respectively). The ability to check the carotid pulse and to perform intramuscular injections was high in post-graduated doctors (90.09% and 81.2%, respectively). DISCUSSION: Although interns believe their knowledge about emergencies to be sufficient, their intervention skills may need to be improved due to the low frequency of encounters. After graduation, their inability to intervene adequately during emergencies in the clinic can lead to fatal consequences. The lack of improvement in doctors' knowledge and intervention abilities with experience could be attributed to insufficient training after completing their formal education. To prevent such scenarios, regular training sessions should be provided to interns and doctors, focusing on the emergencies they may encounter.