Abstract Purpose To characterize buccolingual root dimensions of maxillary lateral incisors using cone beam computed tomography (CBCT) and separately compare post restorations by finite element analysis (FEA) of one tooth geometry. Materials and Methods A CBCT sample of 30 participants with paired maxillary lateral incisors was evaluated at 5–9 mm from the radiologic apex. Buccolingual diameter was analyzed with a linear mixed model incorporating side, measurement level, their interaction, and participant and tooth effects. Separately, one CBCT‐derived baseline geometry was restored with 1.3‐ or 1.6‐mm posts and 1‐ or 2‐mm ferrules. Each configuration received a 200‐N static lateral load at 3 idealized contact sites, yielding 12 deterministic analyses. FEA outcomes were compared descriptively. Results Estimated mean buccolingual root diameter increased from 5.09 mm at 5 mm to 5.80 mm at 9 mm from the radiologic apex. Within the baseline geometry, a 2‐mm ferrule reduced post and crown cement‐layer deformation but increased residual‐tooth deformation. Crown deformation showed no consistent pattern. The Class III‐type contact site produced the highest residual‐tooth stress. Conclusions CBCT findings describe buccolingual root dimensions in the sampled participants. FEA findings describe component‐dependent responses in one geometry and do not predict fracture, fatigue, clinical failure, or patient‐specific treatment outcomes.
Abstract Purpose This study aimed to evaluate the accuracy of a root‐shaped extraction socket–supported guide (ESSG) for anterior single‐tooth immediate implant placement. Materials and Methods After the central incisors were digitally removed from cone beam computed tomography (CBCT) images obtained from patients, 3D‐printed models were created to simulate labial (Type I), central (Type II), and palatal root‐position deviation (Type III) in the sagittal plane. Resin models of each type were divided into high‐elastic‐modulus (HE) and normal‐elastic‐modulus (NE) subgroups. In total, 120 implants were immediately placed using ESSGs (test group) or tooth‐supported surgical guides (TSSGs; control group). The angular and positional deviations were assessed by comparing post‐placement CBCT scans with the corresponding virtual implant plans. Results In Type I and III resin models, angular deviations were significantly smaller in the test group ( p < 0.05) than in the control group, with values of 1.34° ± 0.75° versus 4.28° ± 0.71° (Type I, HE), 0.83° ± 0.76° versus 2.74° ± 1.05° (Type I, NE), 1.18° ± 0.82° versus 3.57° ± 1.40° (Type III, HE), and 1.17° ± 0.79° versus 3.41° ± 1.16° (Type III, NE), respectively. Positional deviations in most Type I and III resin models were likewise significantly lower in the test group than in the control group. Notably, ESSGs maintained high accuracy in HE resin models of Types I and III. Conclusions ESSGs demonstrated greater precision than TSSGs in resin models simulating labial and palatal deviations of socket morphology. Nevertheless, clinical studies are still needed to evaluate their applicability in patients.
ABSTRACT Purpose To evaluate the radiation dose reduction of different materials for intraoral radiotherapy prostheses and spacers with different thicknesses. Materials and Methods Three additively manufactured resins—KeySplint Hard (3D‐Hard), Temporary CB Resin (3D‐TCB), and Saremco Print CROWNTEC (3D‐PCB)—and three elastomeric materials—putty‐type polyvinyl siloxane (PVS‐P), light‐body polyvinyl siloxane (PVS‐L), and polyether (PE)—were prepared with two thicknesses (5 and 10 mm, n = 5 per group). Rectangular specimens were fabricated and positioned over an ionization chamber in a solid–water phantom and measured 15 times with a 6 × 8 cm 2 field. The relative transmitted dose reduction was calculated against the bracketed no‐specimen reference values. Statistical analysis was done using two‐way analysis of variance followed by Games–Howell multiple comparisons. Results Material and thickness significantly affected the relative transmitted dose reduction ( p < 0.05), whereas their interaction was not significant ( p > 0.05). PVS‐P had significantly higher transmitted dose reduction than other materials, regardless of material thickness (3.50% ± 0.21% at 5 mm and 5.57% ± 0.43% at 10 mm). Among the additively manufactured resins, 3D‐PCB demonstrated higher transmitted dose reduction, where a significant effect was found at 10 mm thickness. At 5 mm, no significant difference was observed among three additively manufactured resins. However, at 10 mm, 3D‐PCB (3.83% ± 0.98%) produced significantly greater reduction than 3D‐Hard (3.06% ± 1.05%) and 3D‐TCB (3.13% ± 0.98%). For material thickness, the 10‐mm specimens produced greater reduction than the 5‐mm specimens. Conclusions Under the tested phantom and irradiation conditions, material and thickness influenced the relative transmitted‐dose reduction. The highest transmitted dose reduction was observed in PVS‐P. However, the effects were modest and thickness‐ dependent. These setup‐specific effects do not establish intrinsic material attenuation or clinical tissue protection.
Abstract Purpose To demonstrate the feasibility of a standardized digital workflow for quantifying intersegmental alveolar ridge distance in infants with unilateral cleft lip and palate (UCLP) undergoing presurgical infant orthopedic treatment. Materials and Methods This retrospective pilot feasibility study included six infants with nonsyndromic UCLP. Five infants were treated with presurgical lip, alveolus, and nose approximation, and one was treated with nasoalveolar molding. Serial intraoral scans were obtained at birth, 6 weeks after initiation of therapy, completion of presurgical treatment, and 6 weeks following primary lip repair. Intersegmental alveolar ridge distance was measured digitally as the linear distance between the most lateral aspects of the greater and lesser alveolar segments adjacent to the cleft defect. Results The workflow was successfully applied to serial scans at all evaluated time points. Measurements demonstrated changes in the intersegmental alveolar ridge distance across the treatment timeline, illustrating the ability of the workflow to longitudinally quantify alveolar segment approximation. Conclusions This pilot study demonstrates the feasibility of a standardized digital workflow for objective quantification of intersegmental alveolar ridge distance in infants with UCLP. The workflow provides a potential standardized method for longitudinal measurement of intersegmental alveolar ridge distance and may serve as one component of future multidimensional assessments of presurgical infant orthopedic treatment.
Abstract The rotational path concept can extend beyond simple removable prosthodontics to include maxillofacial prosthetics. In addition to restoring oral continuity, esthetics, and phonetics, these prostheses can improve mastication, speech, and deglutition. Previous studies addressed the general principles of rotational path prostheses and the rehabilitation of partial edentulism with and without dental implants. This study describes the application of this concept in maxillofacial prosthetics through a clinical case presentation.
