Regeneration of emphysematous lungs using gelatin sheets that release basic fibroblast growth factor.

PURPOSE: Basic fibroblast growth factor (bFGF) induces regeneration and neovascularization of the lungs. We conducted this study to demonstrate the regeneration of emphysematous lungs achieved by gelatin sheets that slowly release bFGF into the visceral pleura in a canine model. METHODS: Porcine pancreatic elastase was used to induce bilateral lower lobe pulmonary emphysema in dogs. Slow-release bFGF gelatin sheets were attached to the visceral pleura of the left lower lobe via thoracotomy. The subjects were divided into two groups: one treated with gelatin sheets containing slow-release bFGF (bFGF+ group, n = 5), and the other, treated with only gelatin sheets (bFGF- group, n = 5). The subjects were euthanized after 28 days and histologic lung assessment was performed. The results were evaluated in terms of the mean linear intercept (MLI) and microvessel count. RESULTS: The MLI was significantly shorter in the bFGF+ group than in the bFGF- group; (110.0 ± 24.38 vs. 208.9 ± 33.08 µm; P = 0.0006). The microvessel count was not significantly different between the bFGF+ and bFGF- groups (12.20 ± 3.007 vs. 5.35 ± 2.3425; P = 0.075); however, it was significantly higher in the bFGF-attached lungs than in the emphysema group (12.20 ± 3.007 vs. 4.57 ± 0.8896; P = 0.012). CONCLUSIONS: Attaching gelatin sheets with slow-release bFGF to the visceral pleura induced lung regeneration and vascularization in a canine pulmonary emphysema model.

Safe pneumonectomy for locally advanced lung cancer after induction therapy.

PURPOSE: To assess the safety and long-term outcomes of pneumonectomy after IT (IT-Pn) versus upfront pneumonectomy without IT (U-Pn) for locally advanced non-small-cell lung cancer (NSCLC). METHODS: We reviewed the clinical records of 69 patients who underwent pneumonectomy as U-Pn (n = 30) or IT-Pn (n = 39) between 2000 and 2019 at our institution, RESULTS: U-Pn included patients with pathological N0 (n = 13), N1 (n = 11) and N2 (n = 6). Among the patients treated with IT-Pn, 18 had pathological N0 (including 7 with complete responses), 5 had N1, 14 had N2, and 2 had N3. It was suggested that 22 cases could be down-staged after IT. The 5-year overall survival (OS) was 28.1% in the U-Pn group and 43.1% in the IT-Pn group (p = 0.275), being 40.2% for IT-Pn with p-N2,3, but not reached for U-Pn with N2 (p = 0.307). The 90-day mortality was 6.7% for the U-Pn group and 5.1% for the IT-Pn group (p = 0.646). Major complications occurred in 25 patients (64.1%) treated with IT-Pn and 18 patients treated with U-Pn (60.0%; p = 0.602). CONCLUSIONS: Pneumonectomy for NSCLC can be performed safely after IT with favorable results. For patients with N2 disease, induction therapy followed by surgery may warrant further study.

Flow Microreactor Synthesis of Zeolitic Imidazolate Framework (ZIF)@ZIF Core-Shell Metal-Organic Framework Particles and Their Adsorption Properties.

Metal-organic frameworks (MOFs) with core-shell structures enable to enhance intrinsic properties of constituent MOFs and impart additional functional activities. Although shell thickness is a key factor for regulating the properties of core-shell MOF particles, controlling it has been challenging. The widely used batch reactor synthesis cannot produce core-shell particles with uniform shell thickness because of poor reactant mixing. A microreactor could ensure excellent mixing, and that would allow to control shell thickness. In this study, we synthesized zeolitic imidazolate framework-8 (ZIF-8)@ZIF-67 and ZIF-67@ZIF-8 core-shell particles using a microreactor and investigated the effects of the mixing performance on the shell thickness of the obtained particles. Our results demonstrated that rapid mixing was critical for the uniformity of the synthesized particles. The concentration of core particles is another key factor that can preferentially induce heterogeneous nucleation on the surface of the core particles without inducing self-nucleation in the bulk solution, particularly when the self-nucleation rate of the shell MOF is high. The N2 adsorption isotherms of the synthesized particles revealed their unique adsorption properties, which were ascribed to the core-shell structures obtained at low shell formation rates. Our simple and versatile synthesis technique not only allowed the preparation of ZIF@ZIF particles with novel functionalities but also can be extended to synthesize core-shell MOF particles with different combinations of core particles and shells.

Nonclinical evaluation of abuse liability of the dual orexin receptor antagonist lemborexant.

Lemborexant is a dual orexin receptor antagonist (DORA) approved in multiple countries including the United States, Japan, Canada and Australia for the treatment of adults with insomnia. As required for marketing approval of new compounds with central nervous system activity with sedating effects, the abuse potential of lemborexant was assessed in accordance with regulatory guidelines, which included three nonclinical studies. These assessments comprised physical dependence and drug discrimination studies in rats and a self-administration study in rhesus monkeys. There was no evidence of withdrawal signs following abrupt drug discontinuation, indicating that lemborexant does not induce physical dependence. In the drug discrimination study, lemborexant at doses up to 1000 mg/kg administered orally did not cross-generalize to the zolpidem training stimulus, although another DORA included in the same experiment, suvorexant, showed partial generalization with zolpidem. In rhesus monkeys, lemborexant treatment did not induce any gross behavioral changes, and there was no increase in self-administration rates compared with control, indicative of a lack of reinforcing effects of lemborexant. Collectively, these nonclinical studies support the position that lemborexant, which has been placed in Schedule IV by the United States Drug Enforcement Administration, has a low risk of abuse in humans.

[Anomalous V2 Preoperatively Identified by Three-dimensional Computed Tomography in a Patient with Primary Lung Cancer of Right Upper Lobe].

A 61-year-old woman was found to have multiple ground-glass nodules( GGNs) in both lungs by chest computed tomography (CT) scan. The lesion of the right S2 contained a partial solid component and was suspected to be minimally invasive adenocarcinoma. Three-dimensional CT showed two anomalous V2s descending dorsally to the intermediate bronchus and draining into the inferior pulmonary vein. Thoracoscopic segmentectomy of the right S2 was performed safely. The pathological diagnosis was adenocarcinoma in situ. Since aberrant pulmonary vessels increases the surgical risk during video-assisted thoracoscopic anatomical lung resection, preoperative three-dimensional CT is useful in performing safe surgical procedure.

ADVERSE EFFECT OF MACULAR INTRARETINAL HEMORRHAGE ON THE PROGNOSIS OF SUBMACULAR HEMORRHAGE DUE TO RETINAL ARTERIAL MACROANEURYSM RUPTURE.

PURPOSE: To investigate the clinical course of submacular hemorrhage associated with ruptured retinal arterial macroaneurysm using swept-source optical coherence tomography. METHODS: This study included 23 eyes of 23 consecutive patients diagnosed with submacular hemorrhage associated with ruptured retinal arterial macroaneurysm. Cases underwent displacement of submacular hemorrhage (vitrectomy + subretinal injection of tissue plasminogen activator + air tamponade) and were followed up for 6 months after surgery. Localization of the preoperative hemorrhage and its effect on preoperative and postoperative best-corrected visual acuity, central retinal thickness, and continuity of the ellipsoid zone were measured. RESULTS: Macular intraretinal hemorrhage (IRH) was observed in 17 eyes (73.9%, IRH [+] group) and was not observed in 6 eyes (26.1%, IRH [-] group). The IRH (+) group showed worse postoperative best-corrected visual acuity values compared with the IRH (-) group (0.89 ± 0.47 in logarithm of the minimal angle of resolution units, Snellen equivalent 20/155 and 0.16 ± 0.23, 20/29, respectively; P < 0.01), smaller central retinal thickness values (97.7 ± 53.5 µm, 173.0 ± 32.3 µm, respectively; P < 0.01), and a higher rate of ellipsoid zone disruption (100%, 33.3%, respectively; P < 0.01). CONCLUSION: Patients with preoperative macular IRH showed lower postoperative visual acuity and worse macular contour after submacular hemorrhage displacement compared with patients without macular IRH.

EN FACE IMAGE-BASED ANALYSIS OF RETINAL TRACTION CAUSED BY EPIRETINAL MEMBRANE AND ITS RELATIONSHIP WITH VISUAL FUNCTIONS.

PURPOSE: To evaluate the relationship between retinal traction caused by epiretinal membrane and visual functions. METHODS: In this institutional study, en face swept-source optical coherence tomography images of 141 eyes of 130 patients with epiretinal membrane were analyzed to investigate maximum depth of retinal folds, which represents retinal traction strength and the distribution pattern of retinal folds. We investigated the relationships between the maximum depth and distribution pattern of retinal folds and visual functions as well as the effects of membrane peeling. RESULTS: Maximum retinal fold depth was significantly correlated with the metamorphopsia score (P < 0.001). Fifteen eyes showed retinal folds radially extending from the macular epiretinal membrane (radiating folds group), whereas 126 eyes showed a multidirectional pattern of retinal folds (multidirectional folds group). The radiating folds group showed a significantly lower metamorphopsia score (P = 0.014). Multiple regression analysis revealed that the metamorphopsia score was significantly related to maximum retinal fold depth (P = 0.003), distribution pattern (P = 0.015), and central retinal thickness (P < 0.001). One month after membrane peeling, parafoveal retinal folds resolved completely in all cases, and both visual acuity (P < 0.001) and average metamorphopsia score (P = 0.036) were significantly improved. CONCLUSION: Both the strength and the distribution pattern of retinal traction are significantly related to metamorphopsia in epiretinal membrane patients.

RELATIONSHIP BETWEEN PREOPERATIVE FOVEAL MICROSTRUCTURE AND VISUAL ACUITY IN MACULA-OFF RHEGMATOGENOUS RETINAL DETACHMENT: Imaging Analysis by Swept Source Optical Coherence Tomography.

PURPOSE: To visualize foveal microstructures in macula-off rhegmatogenous retinal detachment using swept source optical coherence tomography preoperatively and postoperatively and to investigate the relationship between foveal microstructures and postoperative visual acuity. METHODS: We retrospectively analyzed 42 eyes of 42 consecutive patients diagnosed with macula-off rhegmatogenous retinal detachment who underwent anatomically successful repair surgery and were followed up for 6 months. We used swept source optical coherence tomography to investigate the relationship between preoperative and postoperative continuity of both the external limiting membrane (ELM) and ellipsoid zone (Ez) and preoperative and postoperative best-corrected visual acuity. RESULTS: Both preoperative ELM and Ez were continuous in 9 eyes (21%; ELM+/Ez+ eyes), only the ELM was continuous in 25 eyes (60%; ELM+/Ez- eyes), and neither was continuous in 8 eyes (19%; ELM-/Ez- eyes). Postoperative best-corrected visual acuity in ELM+/Ez+ eyes (-0.05 ± 0.04 logarithm of the minimum angle of resolution units, Snellen equivalent 20/18) was significantly better than that in both ELM+/Ez- (0.16 ± 0.16, 20/29; P = 0.03) and ELM-/Ez- (0.86 ± 0.37, 20/145; P < 0.001) eyes. Postoperative best-corrected visual acuity was significantly better in ELM+/Ez- than in ELM-/Ez- eyes (P < 0.001). CONCLUSION: In macula-off rhegmatogenous retinal detachment, preoperative continuity of the ELM and Ez may be a predictor of postoperative best-corrected visual acuity.

Choroidal vessel density in unilateral hyperopic amblyopia using en-face optical coherence tomography.

BACKGROUND: Structural changes of the choroid, such as choroidal thickening, have been indicated in amblyopic eyes with hyperopic anisometropia as compared to fellow or healthy eyes. The purpose of the present study was to investigate choroidal vascular density (CVD) in children with unilateral hyperopic amblyopia. METHODS: This study included 88 eyes of 44 patients with unilateral amblyopia due to hyperopic anisometropia with or without strabismus and 29 eyes of 29 age-matched normal controls. The CVD of Haller's layer was quantified from en-face images constructed by 3-dimensional swept-source optical coherence tomography images flattened relative to Bruch's membrane. The analysis area was a 3 × 3-mm square of macula after magnification correction. Relationships between CVD and other parameters [best-corrected visual acuity (BCVA), refractive error and subfoveal choroidal thickness (SFCT)] were investigated, and CVDs were compared between amblyopic, fellow, and normal control eyes. RESULTS: Mean CVD was 59.11 ± 0.66% in amblyopic eyes, 59.23 ± 0.81% in fellow eyes, and 59.29 ± 0.74% in normal control eyes. CVD showed a significant positive relationship with SFCT (p = 0.004), but no relationships with other parameters. No significant differences in CVD were evident among amblyopic, fellow, and normal control eyes after adjusting for SFCT (p = 0.502). CONCLUSIONS: CVD was unrelated to BCVA, and CVD did not differ significantly among amblyopic, fellow and normal control eyes. These results suggest that the local CVD of Haller's layer is unaffected in unilateral hyperopic amblyopic eyes.

Correction to: Stiripentol alleviates neuropathic pain in L5 spinal nerve-transected mice.

In the original publication of the article, the value "40-µm thickness" was incorrect in the legend of Figure 4. The correct value is 10-µm thickness.

Stiripentol alleviates neuropathic pain in L5 spinal nerve-transected mice.

PURPOSE: Antiepileptic drugs are used not only for the treatment of epilepsy but also for that of neuropathic pain. However, their action mechanisms have not always been well explained. Stiripentol, an effective antiepileptic drug indicated as a therapeutic for Dravet syndrome, was recently shown to act as an inhibitor of lactate dehydrogenase in astrocytes. In this present study, we examined the effect of stiripentol on neuropathic pain in L5 spinal nerve-transected mice. METHODS: We carried out behavioral tests using calibrated von Frey filaments and the immunohistochemistry of glial fibrillary acidic protein, an astrocyte marker, in L5 spinal nerve-transected mice after intrathecal administration of drugs. RESULTS: Like other anticonvulsants such as gabapentin and carbamazepine, stiripentol alleviated mechanical hyperalgesia induced by L5 spinal nerve transection in a dose-dependent manner, when intrathecally administered to mice 7, 14, and 28 days after L5 spinal nerve transection. Likewise, α-cyano-4-hydroxycinnamic acid, a broad inhibitor of monocarboxylate transporters, diminished mechanical hyperalgesia induced by L5 spinal nerve transection. Simultaneous administration of L-lactate negated the analgesic effect elicited by stiripentol, carbamazepine or α-cyano-4-hydroxycinnamic acid, but not that by gabapentin. None of the anticonvulsants affected the immunoreactivity of glial fibrillary acidic protein. CONCLUSIONS: This present study demonstrated that stiripentol was effective against neuropathic pain and suggested that the astrocyte-neuron lactate shuttle was involved in such pain.

Development of the ReaxFF Methodology for Electrolyte-Water Systems.

A new ReaxFF reactive force field has been developed for water-electrolyte systems including cations Li+, Na+, K+, and Cs+ and anions F-, Cl-, and I-. The reactive force field parameters have been trained against quantum mechanical (QM) calculations related to water binding energies, hydration energies and energies of proton transfer. The new force field has been validated by applying it to molecular dynamics (MD) simulations of the ionization of different electrolytes in water and comparison of the results with experimental observations and thermodynamics. Radial distribution functions (RDF) determined for most of the atom pairs (cation or anion with oxygen and hydrogen of water) show a good agreement with the RDF values obtained from DFT calculations. On the basis of the applied force field, the ReaxFF simulations have described the diffusion constants for water and electrolyte ions in alkali metal hydroxide and chloride salt solutions as a function of composition and electrolyte concentration. The obtained results open opportunities to advance ReaxFF methodology to a wide range of applications involving electrolyte ions and solutions.

Two-year Results of Intravitreal Ranibizumab Injections Using a Treat-and-extend Regimen for Macular Edema due to Branch Retinal Vein Occlusion.

We investigated the effectiveness of a treat-and-extend regimen (TAE) of intravitreal ranibizumab injections for macular edema (ME) due to branch retinal vein occlusion (BRVO). We retrospectively examined 2-year results of 32 eyes of 32 patients who underwent TAE to treat ME due to BRVO. The patients whose treatment interval extended to ≥ 12 weeks were switched to a pro re nata regimen (PRN). For the patients whose treatment interval was <12 weeks, TAE was continued. At 2 years, 10 eyes had required no additional injections after the initial treatment period [recurrence(-) group], whereas the other 22 eyes required additional treatment [recurrence(+) group]. Among the recurrence(+) patients, 11 eyes (34.4% of total) were eventually switched from TAE to PRN; the other 11 eyes (34.4%) continued TAE for 2 years. Visual acuity and central retinal thickness were significantly improved in both the recurrence(+) and (-) groups, and there was no significant betweengroup difference in visual acuity at 2 years. Univariate analyses revealed significant differences in visual acuity (p=0.004), age (p=0.014), and vessel occlusion site (p=0.018) between these groups. Our results suggest that TAE may be effective for BRVO patients with lower visual acuity, older age, and occlusion of a major vein.

High-Pressure Carbon Monoxide and Oxygen Mixture is Effective for Lung Preservation.

(1) Background: Heme oxygenase-1 (HO-1) degrades heme and generates carbon monoxide (CO), producing various anti-inflammatory, anti-oxidative, and anti-apoptotic effects. This study aimed to confirm the effects of CO on the ischemia-reperfusion injury (IRI) of donor lungs using a high-pressure gas (HPG) preservation method. (2) Methods: Donor rat and canine lungs were preserved in a chamber filled with CO (1.5 atm) and oxygen (O2; 2 atm) and were ventilated with either CO and O2 mixture (CO/O2 group) or air (air group) immediately before storage. Rat lungs were subjected to heterotopic cervical transplantation and evaluated after reperfusion, whereas canine lungs were subjected to allogeneic transplantation and evaluated. (3) Results: Alveolar hemorrhage in the CO/O2 group was significantly milder than that in the air group. mRNA expression levels of HO-1 remained unchanged in both the groups; however, inflammatory mediator levels were significantly lower in the CO/O2 group than in the air group. The oxygenation of graft lungs was comparable between the two groups, but lactic acid level tended to be higher in the air group. (4) Conclusions: The HO-1/CO system in the HPG preservation method is effective in suppressing IRI and preserving donor lungs.

[A Case of Locally Advanced Adenosquamous Carcinoma of the Pancreas Accompanied by Hepatic Metastasis Treated by Resection of the Primary Lesion as Palliative Care].

A 61-year-old man presented to our hospital with appetite loss. Gastroscopy revealed a tumor on the upper body of the stomach. Persistent bleeding was observed from the tumor; therefore, the patient was immediately hospitalized. An abdominal CT scan revealed that the tumor arose from the pancreas and invaded the spleen, stomach, and transverse colon. Furthermore, a hepatic tumor was observed at the posterior segment and blood tests showed increased CA19-9 level. Therefore, the tumor was diagnosed as pancreatic cancer with invasion of the adjacent organs and hepatic metastasis. Although the tumor was classified as unresectable for the distant metastasis, resection of the primary lesion was performed to control the bleeding and obstruction at the invasion sites. The pathological diagnosis of the tumor was adenosquamous carcinoma. The patient subsequently underwent chemotherapy and was discharged from the hospital on postoperative day 34. The patient was able to spend time at home and was treated at an outpatient clinic until postoperative day 110, when his generalcondition deteriorated. In this case, resection of the primary lesion was ineffectual for a life prognosis but was beneficial for palliative care.

Embedding of lamellar hole-associated epiretinal proliferation combined with internal limiting membrane inversion for the treatment of lamellar macular hole: a case report.

BACKGROUND: We recently reported that lamellar macular hole (LMH) with lamellar hole-associated epiretinal proliferation (LHEP) can be effectively treated by embedding the LHEP into the retinal cleavage to improve foveal contour and visual acuity. Here, we report a case of LMH with LHEP for which we performed embedding of the LHEP combined with internal limiting membrane (ILM) inversion. We then evaluated the effects of this surgery on macular morphology and visual functions. CASE PRESENTATION: A 62-year-old man presented with visual disturbance (20/29) and metamorphopsia in his right eye. B-scan optical coherence tomography (OCT) imaging revealed the presence of both partial-thickness defect of the macula with degenerative retinal cleavage and LHEP at the surface of the retina. En face OCT imaging showed the absence of retinal fold. We performed phacoemulsification with intraocular lens implantation, vitrectomy, embedding of LHEP into the retinal cleavage, and ILM inversion. Three months after the surgery, both foveal contour and visual acuity (20/20) were improved and metamorphopsia was reduced. CONCLUSION: Embedding of the LHEP combined with ILM inversion may be an effective treatment for LMH with LHEP.

Successful resolution of coats disease by photodynamic therapy: a case report.

BACKGROUND: Coats disease is a retinal disease characterized by exudative retinal detachment due to abnormal retinal blood vessels. Coats disease is generally treated using laser photocoagulation and cryotherapy to ablate the abnormal retinal blood vessels. However, if abnormal blood vessels are present near the posterior pole of the eye and there is a severe exudative change there, it is difficult to perform these standard treatments. We describe a case of Coats disease with severe exudative retinal change and retinal vascular abnormality near the posterior pole for which we performed photodynamic therapy and successfully suppressed the disease and improved vision. CASE PRESENTATION: A 15-year-old Japanese boy presented to hospital with a chief complaint of decreased vision in his right eye. At the initial examination, corrected visual acuity of the right eye was 20/100. On the right fundus, exudative retinal detachment with subretinal haemorrhage was observed from the upper intermediate periphery to the posterior pole. Abnormal telangiectatic vessels and microaneurysms were found at the nasal peripheral retina. From these findings, we diagnosed the case as Coats disease. We conducted photodynamic therapy for the right eye. At 10 months after treatment, both the subretinal haemorrhage and the exudative retinal detachment had disappeared completely. Further, the retinal structure of the macula had recovered, and right vision had improved to 20/20. CONCLUSION: Photodynamic therapy may be an effective and safe treatment for Coats disease in cases that present with abnormal retinal vessels close to the posterior pole of the eye.

Impact of Polyp Regression on 2-year Outcomes of Intravitreal Aflibercept Injections: A Treat-and-Extend Regimen for Polypoidal Choroidal Vasculopathy.

We conducted intravitreal aflibercept injections (IVAs) for 37 Japanese patients (28 males, 9 females, mean age 73.4 years) with polypoidal choroidal vasculopathy (PCV), with a treat-and-extend regimen (TER). We evaluated the impact of polyp regression after a loading dose (2-mg IVA 1×/month for 3 months) on the patients' 2-year treatment outcomes. Thirty-seven eyes were treated with IVA by a TER for 2 years. We divided the patients into 2 groups based on their polyp status after the loading dose: polyp regression (PR+) (n=19) and no polyp regression (PR-) (n=18). We compared the groups' best-corrected visual acuity (BCVA), central retinal thickness (CRT), recurrence rate, total number of injections, and final treatment interval. Both the BCVA and CRT were significantly improved by the treatment in both groups, with no between-group difference in the amount of change (p=0.769). In the polyp regression (+) group, recurrence was significantly less common (p=0.03), the mean total number of injections was significantly lower (p=0.013), and the mean treatment interval was significantly longer (0.042). Regarding the 2-year outcomes for PCV, the eyes with post-loading-dose polyp regression demonstrated less frequent recurrence and required fewer numbers of injections compared to the eyes without polyp regression.

Results of a Treat-and-Eextend Regimen of Intravitreal Ranibizumab Injection for Macular Edema due to Branch Retinal Vein Occlusion.

To investigate the effectiveness of a treat-and-extend regimen (TAE) of intravitreal ranibizumab injections (IVR) for macular edema (ME) due to branch retinal vein occlusion (BRVO). We retrospectively examined 35 eyes of 35 patients with ME due to BRVO who underwent TAE for 1 year. Patients whose treatment interval extended to 12 weeks were switched to a pro re nata regimen (PRN; TAE to PRN group), while TAE was continued for patients whose treatment interval was less than 12 weeks (continued TAE group). Changes in best-corrected visual acuity (BCVA), central retinal thickness (CRT), and predictive factors for inclusion in the TAE to PRN group were analyzed. BCVA and CRT both improved significantly at 1 year compared with baseline (p<0.001). Sixteen eyes (45.7%) were included in the TAE to PRN group, while 19 eyes (54.3%) were included in the continued TAE group. BCVA in the TAE to PRN group was significantly better than that in the continued TAE group at 1 year (p=0.047). BCVA at baseline and macular BRVO were significant predictive factors for inclusion in the TAE to PRN group. TAE was effective for improving BCVA and CRT. The TAE to PRN group showed significantly better prognosis.

Accuracy and head positioning effects on measurements of anterior tooth length using 3-dimensional and conventional dental panoramic radiography.

INTRODUCTION: The purposes of this study were to examine the accuracy and the head positioning effects on measurements of anterior tooth length using 3-dimensional (3D) and conventional dental panoramic radiography and to investigate whether 3D panoramic radiography is suitable for the evaluation of anterior tooth length. METHODS: A simulated human head was radiographed at 4, 8, and 12 mm displaced positions, and at 5°, 10°, and 15° tilted positions from the standard head position using 3D and conventional panoramic radiography, and also using cone-beam computed tomography. Anterior tooth lengths were measured on the panoramic and cone-beam computed tomography images. The values for the standard head position in the panoramic radiographs were defined as the standard values. Measurement error was defined as the standard value minus the cone-beam computed tomography value on each panoramic radiograph. The head position ratio of the measurement value to the standard value at each head position was calculated. RESULTS: Measurement errors for the 3D panoramic radiographs were significantly smaller than those for the conventional panoramic radiographs. In the 3D panoramic radiographs, the head position ratios at the 4, 8, and 12 mm displaced positions and at the 5° tilted position were within ±5% of the standard value. CONCLUSIONS: Three-dimensional panoramic radiography is suitable for the quantitative evaluation of anterior tooth length with high accuracy.