Effect of Solid-State Phase Transformation and Transverse Restraint on Residual Stress Distribution in Laser-Arc Hybrid Welding Joint of Q345 Steel.

A Q345 steel butt-welded joint was manufactured using laser-arc hybrid welding (LAHW) technology, and its microstructure, microhardness, and residual stress (RS) distribution were measured. Using ABAQUS software, a sequentially coupled thermo-metallurgical-mechanical finite element method was employed to model the welding RS distribution in the LAHW joint made of Q345 steel. The effects of solid-state phase transformation (SSPT) and transverse restraint on the welding RS distribution were explored. The results show that a large number of martensite phase transformations occurred in the fusion zone and heat-affected zone of the LAHW joint. Furthermore, the SSPT had a significant effect on the magnitude and distribution of RS in the LAHW joint made of Q345 steel, which must be taken into account in numerical simulations. Transverse restraints markedly increased the transverse RS on the upper surface, with a comparatively minor impact on the longitudinal RS distribution. After the transverse restraint was released, both the longitudinal and transverse RS distributions in the LAHW joint reverted to a level akin to that of the welded joint under free conditions.

Diagnosis and Treatment of Radioactive Iodine-Induced Sialadenitis: A 10-Year Endoscopic Experience.

OBJECTIVES: The aim of this study was to explore the endoscopic characteristics of radioactive iodine-induced sialadenitis (RAIS), and to evaluate the treatment outcomes of endoscopic intervention for RAIS. STUDY DESIGN: Retrospective case series. METHODS: Eighty-two consecutive patients (11 males and 71 females) diagnosed as RAIS from Nov. 2012 to Sep. 2023 were retrospectively included. All patients underwent endoscopic exploration and intervention of the affected glands. The endoscopic features were collected, and treatment outcomes were followed-up and evaluated through post to pre-operative comparisons of gland status. RESULTS: Overall, endoscopic procedures were undertaken for 162 parotid glands (PGs) and 62 submandibular glands (SMGs). Endoscopy showed severe lumen stricture (49.3%) and ductal atresia (23.5%) in PGs, as well as severe stenosis of the anterior duct and ectasia of the proximal duct (59.7%) in SMGs. During a median six months' follow-up, the treatment outcomes of PGs were evaluated as "improvement" in 23.4%，"lesion maintenance" in 45.1% and "lesion aggravation" in 31.5% of the glands. As for SMGs, the treatment outcomes were scored as "improvement"in 29.0%，"lesion maintenance"in 54.8%, and"lesion aggravation"in 16.1% of the glands. No significant differences of treatment outcomes were found relative to RAI treatment sessions and cumulative dosage. CONCLUSION: RAIS is characteristic of severe lumen stricture and ductal atresia in PGs, and stenosis of the distal duct and ectasia of the proximal duct in SMGs. Endoscopy can alleviate clinical symptoms of RAIS and help to preserve the gland function. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:4506-4513, 2024.

Histopathological changes in salivary glands after radioactive iodine treatment for thyroid diseases.

OBJECTIVES: We aimed to evaluate the histopathological alterations in human salivary glands after radioactive iodine (RAI) treatment for thyroid diseases. STUDY DESIGN: We retrospectively selected patients with a history of RAI treatment for thyroid diseases from a database of patients who underwent surgery for oral and maxillofacial diseases and had specimens of salivary glands at Peking University School of Stomatology between December 2012 and July 2023. The patients' clinical records and histopathological slides of the salivary glands were carefully reviewed. RESULTS: Sixteen patients were included. Three symptomatic patients showed duct cell cytoplasmic vacuolization and increased numbers of disordered duct cell layers (3/3), severe duct stenosis and dilation (2/3), and exfoliated epithelial cells in the duct lumen (1/3). The glandular parenchyma showed severe acinar atrophy (2/2), fat content enhancement (2/2), and severe periductal fibrosis (3/3). Thirteen asymptomatic patients showed duct cell cytoplasmic vacuolization (5/13), acinar atrophy and increased fat content in the parenchyma (5/13), and periductal fibrosis (5/13). CONCLUSION: Main histopathologic changes in the salivary glands after RAI treatment for thyroid diseases are cytoplasmic vacuolization of duct cells, acinar atrophy, fat content enhancement, and periductal fibrosis. These changes were evident in symptomatic cases, and were also seen in some asymptomatic patients.

[Three-dimensional radiographic features of calcifying odontogenic cyst and calcifying epithelial odontogenic tumor].

OBJECTIVE: To analyze the three-dimensional radiographic characteristics of calcifying odontogenic cyst and calcifying epithelial odontogenic tumor using spiral computed tomography (CT) and cone-beam computed tomography (CBCT). METHODS: Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 19 consecutive patients with calcifying odontogenic cyst (COC) and 16 consecutive patients with calcifying epithelial odontogenic tumor (CEOT) were retrospectively acquired, and radiographic features, including location, size, expansion, internal structure and calcification, were analyzed. RESULTS: Among the 19 COC cases (12 males and 7 females, with an average age of 27 years), 89.5% (17/19) of the lesions originated from the anterior and premolar areas, 100.0% of them exhibited cortex expansion, and 78.9% had discontinued cortex. Among the 16 CEOT cases (3 males and 13 females, with an average age of 36 years), 81.3% (13/16) of the lesions were in the premolar and molar areas, 56.3% of them exhibited cortex expansion, and 96.8% had discontinued cortex. According to the distribution of internal calcifications, these lesions were divided into: Ⅰ (non-calcification type): absence of calcification; Ⅱ (eccentric marginal type): multiple calcifications scattered along one side of the lesion; Ⅲ (diffused type): numerous calcifications diffusely distributed into the lesion; Ⅳ (plaque type): with a ≥ 5 mm calcified patch; Ⅴ (peri-coronal type): multiple calcifications clustered around impacted teeth. Calcifications were present in 73.7% of COC lesions, including 9 type Ⅱ, 3 type Ⅲ and 2 type Ⅳ lesions, and 42.8% of CEOT lesions had calcification images, including 2 type Ⅲ and 5 type Ⅴ lesions. Six COC lesions had odontoma-like images. Moreover, 8 of 9 type Ⅰ CEOTs were histologically Langerhans cell-rich subtype, which had a smaller size (with an average mesiodistal diameter of 17.8 mm) and were not associated with impacted teeth. CONCLUSION: COC lesions tended to originate from the anterior part of the jaw and exhibit cortex expansion, and were sometimes associated with odontoma. CEOT commonly occurred in the posterior jaw and had discontinued cortex. Two lesions had significantly different calcification map. Over 70% of COC lesions had calcification images, which were mostly scattered along one side of the cysts, far from the impacted teeth. Approximately 60% of CEOT lesions exhibited smaller size and non-calcification, and the remaining CEOT cases often had calcification images clustered around the impacted teeth.

Imaging-based diagnosis and classification of radioactive iodine-induced sialadenitis.

OBJECTIVES: To establish an inflammation grading system for radioactive iodine-induced sialadenitis (RAIS) based on spiral computed tomography (CT), ultrasonography and sialography. METHODS: In all, 120 RAIS patients (18 males and 102 females) were retrospectively included. Spiral CT, ultrasonography and sialography appearances were analysed and categorized as follows: grade I, approximately normal or mild sialadenitis; grade II, moderate sialadenitis; and grade III, severe sialadenitis. Adenitis severity was analysed relative to sex, age, RAI treatment sessions and cumulative doses. RESULTS: Spiral CT showed heterogeneous (78.9%) and atrophic changes (36.8%) in the parotid glands (PGs) and duct ectasia (24.8%) in the submandibular glands (SMGs). Ultrasonography showed heterogeneous echogenicity (54.3%) and diminished gland size (30.2%) in PGs and duct ectasia in SMGs (34.7%). Sialography showed duct obliteration in 25.3% PGs and 3.2% SMGs. Statistical analysis showed good consistency among the three imaging grading results. The incidence and severity of PG lesions were significantly higher than that of SMGs (p < 0.001). As for PGs, adenitis severity was associated with both treatment sessions and cumulative doses; but in SMGs, disease severity was only related to treatment sessions. CONCLUSIONS: A grading system for severity of RAIS was established based on spiral CT, ultrasonography and sialography appearances.

Confirmation of eosinophilic sialodochitis by terminal duct biopsy.

OBJECTIVE: To analyse the histopathological features of eosinophilic sialodochitis by using terminal duct biopsy. METHODS: Sixty-five patients with suspected eosinophilic sialodochitis and four with chronic obstructive sialadenitis were prospectively enrolled. Clinical features, laboratory tests and sialograms were comparatively analysed. Terminal duct biopsy of the parotid or submandibular glands was performed concomitantly with endoscopy-assisted duct dilatation to determine the histopathological features of eosinophilic sialodochitis. RESULTS: Based on eosinophil quantification, the samples of suspected patients were scored as 'definite', 'highly suspected' and 'negative' in 26 (40%), 15 (23.1%) and 24 (36.9%) cases, respectively. Gland types and peripheral blood eosinophil counts were significantly different among these three groups. The proportions of itching glands, mucus plug exudations and elevated immunoglobulin E levels were higher in the 'definite' group than in the other two groups; however, the intergroup differences were insignificant. The primary pathological features of eosinophilic sialodochitis were abundant eosinophils and lymphocytes infiltrated around the duct, degranulation of eosinophils, extensive fibrosis and scattered mastocytes. Periductal eosinophils were not found in cases of chronic obstructive sialadenitis. CONCLUSION: Our findings suggest that terminal duct biopsy is safe and valuable for the pathological confirmation of eosinophilic sialodochitis, and can be used simultaneously with endoscopy-assisted duct dilatation.

Morphologic analysis of alveolar bone in maxillary and mandibular incisors on sagittal views.

PURPOSE: The aim of this study was to analyze the morphologic features of alveolus in relatively healthy maxillary and mandibular incisors using cone-beam-computed tomography (CBCT). METHODS: CBCT images of 318 patients were retrospectively acquired. Alveolar bone in incisive area was divided into: type 1 (thick), type 2 (relatively thick with mono-plate concavity), type 3 (thin with double-plate concavities), and type 4 (vulnerably thin). Alveolus prevalence and widths were analyzed statistically relative to age, gender, and molar relationship. RESULTS: Prevalence of type 1 alveolus was 78.9% in maxillary central incisors, 15.1% in maxillary lateral incisors, 24.1% in mandibular central incisors, and 5.0% in mandibular lateral incisors. Type 2 alveolus was commonly observed in the maxillary lateral incisors (82.2%), mandibular central incisors (66.2%), and mandibular lateral incisors (87.9%). Prevalence of type 3 and 4 alveoli ranged from 0.0 to 9.4%. As for maxillary central incisors, type 1 was the widest both at the alveolar crest (7.77 ± 0.58 mm) and apical area (9.05 ± 1.86 mm), while type 3 had the lowest width at the apical region (4.08 ± 0.51 mm). Among maxillary central incisors, prevalence of type 1 tended to decrease with age. At all maxillary and mandibular incisor sites, alveolus widths were significantly thicker in males than in females. At maxillary lateral incisor and mandibular incisor sites, prevalence of alveolus type was significantly different among three molar relationships. CONCLUSION: A 4-type classification system was suggested for alveolus morphology in incisive region. Identification of alveolus type might aid in the corresponding treatment.

Allergy-Related Sialodochitis: A Preliminary Cohort Study.

OBJECTIVES/HYPOTHESIS: To explore the clinically feasible diagnosis criteria and treatment outcomes of allergy-related sialodochitis (ARS). STUDY DESIGN: Prospective Cohort Study. METHODS: Ninety-six consecutive patients were enrolled by the following criteria: 1) recurrent swelling of ≥2 large salivary glands that lasted for ≥3 months; 2) with mucus plug exudations; 3) with atopic diseases; 4) ductal stenosis and/or ectasia. Sixty-four patients with elevation of peripheral blood eosinophil (PBE) and/or serum IgE level comprised group A (highly-suspected ARS group), while the remaining 32 comprised group B (patients without confirmed evidence of ARS). These patients were treated with interventional endoscopy. A chronic obstructive sialadenitis symptom (COSS) questionnaire was used to quantify the treatment outcomes. RESULTS: In group A, Serum IgE was elevated in 84.4% of patients and PBE was elevated in 34.4% of patients. Percentage of submandibular gland involvement was higher in group A than group B (48.4% vs. 18.8%). On sialograms, the snowflake changes of branch ducts were seen in higher percentage of group A compared with group B (59% vs. 35% for parotid glands, 27% vs. 8% for submandibular glands, respectively). Mucus plug smears showed abundant eosinophils in 14 group A patients. Biopsy of five group A patients revealed significant eosinophil infiltration around the main and interlobular ducts. During follow-up, the COSS scores were significantly decreased in both groups, and group B was improved better than group A. CONCLUSION: PBE and serum IgE are important diagnostic indexes of ARS. Mucus plug smear or histopathology verifies the diagnosis. Interventional endoscopy is helpful for ARS cases. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2030-2035, 2021.

Eosinophilic Sialodochitis: A Type of Chronic Obstructive Sialadenitis Related to Allergy.

OBJECTIVES: To investigate the clinical, laboratory, radiological, histopathological, and immunohistochemical features, and the expression of allergy-related cytokines in eosinophilic sialodochitis (ES). METHODS: Thirty-eight patients diagnosed with chronic obstructive sialadenitis (COS) who had undergone glandular excision or incisional biopsy were enrolled. Seventeen patients with comorbid atopic disease and increased ductal tissue eosinophils comprised the ES group, while 21 patients comprised the COS group. The clinicopathological features and allergy-related cytokine expression were compared between groups. RESULTS: The ES group frequently involved multiple, bilateral major salivary glands, and the number of glands was significantly greater than the COS group (2.8 ± 1.1 vs. 1.2 ± 0.4, P < .001). Serum immunoglobulin (Ig) E was elevated in 91% of patients in ES group (419 ± 357 kU/L) and peripheral blood eosinophil was significantly greater compared with the COS group (7.6% ± 4.6% vs. 2.5% ± 1.4%, P < .001). Histologically, eosinophil infiltration in ES group was observed around the main and interlobular ducts (50 ± 39/high power field [HPF]). Follicular hyperplasia (76%), epithelial mucous metaplasia (82%), and mucus plugs with eosinophils (41%) were observed. IgE-positive cell count was 20.7 ± 18.3/HPF and tryptase-positive mast cell count was 23.5 ± 15.1/HPF, which was significantly greater than the respective cell counts in COS group, which mainly infiltrated around the ducts. The levels of interleukin-4, interleukin-13, and eotaxin in tissue were significantly greater in ES than the COS group. CONCLUSIONS: The clinicopathological characteristics of ES are significantly different from COS and ES might have an allergy-related pathogenesis. LEVEL OF EVIDENCE: 4 Laryngoscope, 131:E800-E806, 2021.

Potential biological damage of human peripheral blood lymphocytes induced by computed tomography examination of the oromaxillofacial region.

OBJECTIVES: The aim of this study was to examine whether oromaxillofacial computed tomography (CT) examination causes biologic damage in lymphocytes and whether the biologic damage is related to radiation dose, patient age, or gender. STUDY DESIGN: Peripheral blood was taken from 51 individuals and divided into control, in vivo, and in vitro irradiation groups. Biologic damage was assessed by comparing rates of chromosomal aberrations (CAs), including dicentric chromosomes (dics), centric rings, and acentric fragments; and nuclear aberrations, including micronuclei (MN), nuclear buds (NBUDs), and nucleoplasmic bridges (NPBs) in the peripheral blood before and after CT examination. Absorbed and effective doses were calculated with the software VirtualDose, and the blood dose was estimated accordingly. RESULTS: The rates of acentric fragments, MN, NBUDs, and NPBs in the in vivo (P ≤ .008) and in vitro (P ≤ .003) irradiation groups were significantly higher than those in the control groups. The acentric fragment rate (P = .013) and MN rate (P = .002) were higher in the in vitro group than in the in vivo group. There was no correlation between change rates of CAs and nuclear aberrations with radiation dose. Positive correlations of MN rates with age were found in all groups (ρ ≥ 0.590). CONCLUSIONS: Certain doses of radiation in oromaxillofacial CT examination may induce CAs and nuclear aberrations in lymphocytes.

DNA double-strand breaks of human peripheral blood lymphocyte induced by CT examination of oral and maxillofacial region.

OBJECTIVES: To explore whether a computed tomography (CT) examination of the head and neck region induces biological damage and whether the damage was correlated with the radiation dose. MATERIALS AND METHODS: Peripheral blood was taken from 33 individuals who received head and neck CT examinations. Blood samples were divided into three groups: the control group and the in vivo and in vitro irradiation groups. The number of DNA double-strand breaks was estimated by comparing the changes in the rates of γ-H2AX foci formation in the peripheral blood before and after CT examination. The absorbed dose and effective dose were calculated with the software VirtualDose based on the Monte Carlo method, and the absorbed doses in blood were estimated accordingly. RESULTS: The γ-H2AX foci rates were increased in the in vivo (p < 0.001) and in vitro irradiation groups (p < 0.001) after CT examination when compared with those in the control group. The rate of γ-H2AX foci formation showed linear dose-responses for the CT dose index volume (CTDIvol), dose-length product (DLP), and blood dose after CT examination. CONCLUSIONS: A CT examination of the head and neck region provides a high enough radiation dose to induce DNA double-strand breaks in cells in the peripheral blood. There was a linear correlation between the formation of DNA double-strand breaks and radiation doses after CT examination. CLINICAL RELEVANCE: In addition to ensuring image quality, in a real clinical situation, the scanning area should be strictly administered, and repeated operations should be avoided to minimise the patient's radiation dose.

Treatment strategy of hilar and intraglandular stones in wharton's duct: A 12-year experience.

OBJECTIVES/HYPOTHESIS: To suggest a strategy for transoral removal of hilar and intraparenchymal submandibular stones. STUDY DESIGN: Retrospective case series. METHODS: Retrospective evaluation was performed for 514 consecutive patients with hilar and intraparenchymal submandibular stones treated via endoscopy-assisted surgery from January 2006 to June 2018. Three patients had bilateral stones. The stones were classified as: hilar (type I), posthilar (type II), intraparenchymal (type III), and multiple stones (type IV). RESULTS: The affected glands included 311 with type I, 84 with type II, 65 with type III, and 57 with type IV stones. Stones were successfully removed in 478 glands (92.5%, 478/517). Main treatment techniques included hilum ductotomy in 311 glands, intraparenchymal ductotomy in 68, submandibulotomy in 14, intraductal retrieval in 74, and hilum ductotomy accompanied by intraductal retrieval in 11. At a mean 40-months follow-up of 478 successful cases, clinical outcomes were good in 425, fair in 27, and poor in 26 glands. Postoperative sialograms in 75 stone-free patients were categorized as: type I, normal (n = 6); type II, ectasia or stenosis in the main duct and no persistent contrast on functional films (n = 44); type III, ectasia or stenosis in the main duct and mild contrast retention (n = 15); and type IV, poor shape of the main duct and evident contrast retention (n = 10). Postoperative sialometry of 32 patients revealed no significant differences of the gland function between the two sides. CONCLUSIONS: Appropriate use of various endoscopy-assisted approaches helps preserve the gland and facilitates recovery of gland function in patients with different depths of hilo-parenchymal submandibular stones. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:2360-2365, 2020.

Three-dimensional radiographic features of ameloblastoma and cystic lesions in the maxilla.

OBJECTIVES: To characterize the radiographic features of maxillary ameloblastoma (AM), odontogenic keratocyst (OKC) and dentigerous cyst (DC) comparatively by using spiral CT and cone beam CT (CBCT). METHODS: Clinical records, histopathological reports, and nonenhanced spiral CT or CBCT images of 191 consecutive patients with primary maxillary AMs, OKCs, or DCs were retrospectively acquired, and radiographic features were analyzed. RESULTS: The study included 118 males and 73 females (age: 5-84 years). 72.0% of AMs and 84.3% of OKCs originated from the posterior maxilla, while 69.6% of DCs occurred in the anterior maxilla. Among 25 AMs, 44.0% were of desmoplastic type, with honey-combed appearance. 84.0% of AMs were circular or oval in shape, 84.0% expanded buccally, and 36.0% invade the nasal floor. Among 89 OKCs of 88 patients, 61.8% were circular or oval, 58.4% expanded buccally, 49.4% were dentigerous, 41.6% nearly filled the maxillary sinus, and 13.5% invaded the nasal floor. 93.7% (74/79) of DCs enveloped a single tooth, and the tooth-cyst relationship was centripetal in 35, eccentric in 30, and circumferential in 9. Moreover, 98.2% (55/56) of the cysts enveloping a supernumerary tooth were DCs, while 80.9% (38/47) of the cysts enveloping the third molar were OKCs. CONCLUSIONS: Maxillary AMs tend to grow with buccal expansion and invade the nasal floor, and DAs with honey-combed lobularity are common. Maxillary OKCs have variant shapes and tend to invaginate the maxillary sinus. The tooth-cyst relationship of dentigerous OKCs and DCs can be centripetal, eccentric, or circumferential.

Evaluation of Parotid Gland Function Before and After Endoscopy-Assisted Stone Removal.

PURPOSE: To quantify gland function before and after endoscopy-assisted lithectomy for patients with parotid stones and to analyze correlations among different evaluation modalities. MATERIALS AND METHODS: This study investigated 58 patients (27 men and 31 women) with a stone larger than 5 mm or multiple parotid stones who underwent successful endoscopy-assisted surgery at the authors' center from August 2007 through September 2017. Meticulous postoperative manipulations were administered routinely for 3 to 6 months to promote functional recovery of the affected gland. Gland function was evaluated preoperatively and 6 to 36 months (mean, 12 months) postoperatively by sialography, scintigraphy, and sialometry. Statistical analyses were conducted to quantify gland function recovery and to distinguish correlations among the 3 objective tests. RESULTS: Preoperative sialograms exhibited ductal ectasia at the stone site with ductal stenosis anterior to the stone (n = 53) or duct interruption at the stone site (n = 5). Postoperative sialograms of 45 patients without stones were categorized as approximately normal (type I; n = 17); showing ectasia or stenosis of the main duct without persistent contrast on the functional film (type II; n = 16); showing ectasia or stenosis of the main duct with mild contrast retention (type III; n = 6); or showing poor ductal shape with evident contrast retention (type IV; n = 6). Scintigraphy of 23 preoperative and 12 postoperative patients and sialometry of 24 preoperative and 12 postoperative patients indicated severe preoperative impairment and postoperative improvement of gland function. Postoperatively, although no relevant differences in saliva flow rate were found between the 2 sides, scintigraphy showed lower function of the affected gland compared with the control side. Statistical data showed positive correlations among the 3 methods. Sialography intuitively reflected the ductal shape, whereas sialometry and scintigraphy were more sensitive for evaluating gland function. CONCLUSION: For patients with parotid stones, minimally invasive endoscopic surgery and meticulous postoperative manipulations help preserve the glands and facilitate recovery of gland function. The 3 evaluating modalities have certain positive correlations.

Bifid variations of the mandibular canal: cone beam computed tomography evaluation of 1000 Northern Chinese patients.

OBJECTIVES: The aim of this study was to evaluate and quantify variations of bifid mandibular canals (BMCs) in a population of Northern China by using cone beam computed tomography (CBCT). STUDY DESIGN: CBCT images of 1000 consecutive patients were analyzed by using the NewTom proprietary software. BMCs were identified and classified on the basis of the Naitoh classification. Linear and angular measurements of BMCs were performed. Statistical analyses were conducted by using χ2 and Wilcoxon tests. RESULTS: BMCs were observed in 13.2% of 1000 patients and 8.4% of 2000 sides. The prevalence of BMCs was significantly lower in patients in the first 2 decades and in cases with a class II molar relationship. The retromolar canal (68.4%) was the most common type of BMC observed. No buccolingual canals were identified; however, 2 special canals were detected. A classification system of 3 subtypes of retromolar canals was suggested. On average, the beginning site of the branches from the opening of the main canal was at a distance of 8.1 mm. The mean diameter and length of BMCs were 2.1 mm and 12.6 mm, respectively. CONCLUSIONS: This study underlined the prevalence and characteristics of BMCs in a population of Northern China. Preoperative identification of BMCs with CBCT may help prevent postoperative complications.

Transoral and transcutaneous approach for removal of parotid gland calculi: a 10-year endoscopic experience.

OBJECTIVE: The aim of the study was to evaluate the safety, effectiveness, and long-term gland function of endoscopy-assisted lithectomy for extraction of parotid gland calculi. STUDY DESIGN: Overall, 116 consecutive patients with parotid gland calculi underwent endoscopy-assisted lithectomy at our center. The immediate safety and effectiveness were evaluated. After surgery, the patients were followed up, and gland function was analyzed on the basis of clinical manifestations and sialography. RESULTS: Complete stone extraction was achieved in 110 cases (110 of 116 [94.8%]) by using a transoral (95 cases) or transcutaneous (15 cases) approach. At a median follow-up of 3 years, clinical outcomes were excellent in 86 cases (78.2%), fair in 16 cases (14.5%), and poor in 5 cases (4.5%). Postoperative sialographic appearance in 30 stone-free patients was categorized into 3 types: (1) normal (13 cases); (2) ectasia or stenosis in the main duct but no persistent contrast, as seen on functional films (10 cases); and (3) ectasia or stenosis in the main duct and persistent contrast evident on functional films (7 cases). CONCLUSIONS: In the absence of lithotripsy, appropriate application of various minimally invasive endoscopic procedures has confirmed safety and effectiveness for stone extraction in patients with parotid calculi. Sialography is a viable method for the evaluation of postoperative gland function.

Double Roots of Mandibular Premolar in Full-mouth Periapical Films.

OBJECTIVE: To evaluate the incidence of two-rooted mandibular premolar morphology using full-mouth periapical film series in a Chinese population, with particular emphasis on bilateral incidence, so as to provide a clinical anatomical basis for root canal treatment in mandibular premolars. METHODS: A total of 2015 patients who underwent dental treatment and had full mouth periapical radiographs at the Peking University School of Stomatology from April 2011 to April 2012 were enrolled in this study. Three experienced dentists reviewed the patients' periapical films and classified the root morphology of mandibular premolars bilaterally. The incidence of unilateral and bilateral double roots were recorded and calculated, including confirmed and suspected bucco-lingual root types. RESULTS: In terms of the morphology of two-rooted mandibular first premolars, of the 2015 cases with complete root formation, two-rooted first premolars were detected in 120 cases, with a total number of 159 teeth. According to the number of teeth, the overall incidence of double roots was 4.03% (159/3972). In terms of the morphology of two-rooted mandibular second premolars, of the 2015 cases with complete root formation, two-rooted second premolars were detected in 24 cases, with a total number of 33 teeth. According to the number of teeth, the overall incidence of double roots was 0.85% (33/3880). CONCLUSIONS: The roots of mandibular premolars display specific morphological patterns. Based on a large sample, we observed and calculated not only the occurrence rate of bucco-lingual and mesio-distal double roots in first and second mandibular premolars, but also the incidence of unilateral or bilateral double roots within the same mandible. These findings could provide useful information on the anatomical structure of mandibular premolars for endodontic, prosthodontic and surgical procedures, and could improve the quality of treatment and reduce complications.

A novel technique for measurement of dentogingival tissue by cone beam computed tomography.

OBJECTIVES: To develop a novel technique to visualize dentogingival profiles by using cone beam computed tomography (CBCT) and to evaluate the accuracy of mucogingival tissue thickness measurements with CBCT, as compared with direct measurements in vitro. METHODS: A silicone matrix loaded with radiopaque impression material was prepared before performing CBCT on a patient. Two dry cadaver mandibles with simulated mucogingival tissue and six segmental cadaver jaws were used to assess the accuracy of mucogingival tissue thickness measurements directly and radiographically with CBCT images. Paired t tests were used to evaluate the intra- and interexaminer reliability and to compare the data between direct and CBCT imaging measurements at α = 0.05. RESULTS: No statistically significant differences were observed between direct and CBCT imaging measurements of simulated mucogingival tissue thickness in mandibular models and in cadaver jaws (P > .05). Results of direct measurements with simulated mucogingival tissue thickness indicated good intra- and interexaminer reliability. CONCLUSIONS: A novel technique was developed to obtain mucogingival tissue thickness data on the use of radiopaque impression materials and CBCT imaging. This new method provides a reliable visual dentogingival profile and a means to objective measurements.

[Effect of regenerative therapy for the furcation involvements of mandibular molars evaluated by cone-beam computed tomography].

OBJECTIVE: To evaluate the effect of regenerative therapy for the treatment of furcation involvements of mandibular molars with cone-beam computed tomography (CBCT). METHODS: In the study, 38 furcation involvements of mandibular molars were included and randomly divided into two groups. The experimental group accepted guided tissue regeneration and bone graft therapy, and the control group only flap surgery. The clinical examination and CBCT examination were performed at baseline and 1 year post-surgery. RESULTS: The clinical and CBCT data of both groups were not statistically different at baseline (P>0.05). At the end of 1 year post-surgery, except gingival recession, the clinical parameters of both groups were significantly improved (P<0.001). The vertical and horizontal attachment gains of the experimental group were (3.20 ± 1.82) mm and (2.05 ± 1.27) mm, respectively, and significantly higher than the changes of the control group (P<0.001). And at the end of 1 year post-surgery, the experimental group showed significantly higher bone gain at the vertical and horizontal directions compared with those of the control group: (2.82 ± 0.97) mm and (2.24 ± 0.92) mm, respectively (P<0.001). CONCLUSION: With the limitation of this study, the effect of guided tissue regeneration surgery and bone graft therapy for the treatment of furcation involvements of mandibular molars is significantly better than that of the flap surgery. CBCT can reflect the horizontal and vertical bone changes of furcation area, which is more comprehensive than traditional periapicals.

Obstructive sialadenitis of a transplanted submandibular gland: chronic inflammation secondary to ductal obstruction.

AIMS: To determine the pathological basis and clinical features of obstructive sialadenitis in transplanted submandibular glands (SMGs). METHODS: A total of 161 patients (174 eyes) with keratoconjunctivitis sicca underwent microvascular SMG transplantation. Patients were followed up at approximately 1 and 4 months and annually thereafter. Clinical data, including dry eye discomfort, symptoms of ductal obstruction, and Schirmer test, were recorded. Sialography was performed in six patients. In addition, SMG autotransplantation was performed in 22 rabbits. Salivary flow was recorded and the morphology of glands was examined at 6 months postoperatively by light microscopy. RESULTS: Among the patients, 16 out of 172 glands during the latent period (0-3 months) and 2 out of 154 glands with long-term follow-up (>1 year) showed obstructive sialadenitis. Typical manifestations were continuous small volumes of viscous secretions, recurrent gland swelling, decreased Schirmer test values, and irregular dilation of the main duct on sialography. The transplanted SMGs eventually showed no secretion in five cases. Of the 22 rabbit SMGs, 4 had obstructive sialadenitis. Morphological examination showed chronic inflammatory infiltration with salivary deposits. CONCLUSIONS: Obstructive sialadenitis of transplanted SMGs is a chronic inflammation secondary to ductal obstruction, which leads to insufficient ocular lubrication and potential treatment failure.