Radiographic changes of mandibular cortical bone in bisphosphonate drug holiday

Objectives

There have been few studies to date on the residual effect of bisphosphonate. This study investigated the radiographic changes of mandibular cortical thickness upon bisphosphonate drug holiday.

Materials and Methods

This retrospective study includes 36 patients diagnosed with MRONJ (medication-related osteonecrosis of the jaw) at Ajou University Dental Hospital in 2010-2021. All patients stopped taking bisphosphonate under consultation with the prescribing physicians. Panoramic radiographs were taken at the start of discontinuation (T₀), 12 months after (T₁), and 18 months after (T₂) discontinuation of bisphosphonate, respectively. Mental index and panoramic mandibular index were calculated using Ledgerton’s method. Paired t-tests were used to analyze differences over time.

Results

The difference in indices (mental index and panoramic mandibular index) between T₀ and T₁ was not statistically significant (paired t-test, P>0.05). However, the difference in these indices between T₁ and T₂ was statistically significant (paired t-test, P<0.05).

Conclusion

The cortical thickness of the mandible decreased in the late stage (after 18 months) as observed by panoramic radiograph.

Regenerative effect of recombinant human bone morphogenetic protein-2/absorbable collagen sponge (rhBMP-2/ACS) after sequestrectomy of medication-related osteonecrosis of the jaw (MRONJ)

Objectives

Beyond the original application approved by the U.S. Food and Drug Administration, recombinant human bone morphogenetic protein-2 (rhBMP-2) is used for medication-related osteonecrosis of the jaw (MRONJ) treatment because of its bone remodeling enhancement properties. The purpose of the study was to investigate the bone formation effect of rhBMP-2/absorbable collagen sponge (ACS) in patients with MRONJ.

Materials and Methods

In this retrospective cohort study, 26 female patients diagnosed with MRONJ and who underwent mandibular sequestrectomy at Ajou University Dental Hospital from 2010 to 2018 were included. The experimental group was composed of 18 patients who received rhBMP-2/ACS after sequestrectomy, while the control group was composed of 8 patients who did not receive rhBMP-2/ACS after sequestrectomy. A total dose of 0.5 mg of rhBMP-2 was used in the experimental group at a concentration of 0.5 mg/mL. Follow-up panoramic X-rays were taken immediately after the surgery and more than 6 months after the surgery. Using those X-rays, a radiographic index of bone defect area was calculated using the modified Ihan Hren method, which measures radiographic density of the normal bone and the defect site.

Results

This study suggests that rhBMP-2 contributes to new bone formation. The mean radiographic index immediately after surgery and more than 6 months after the surgery for the experimental group was 68.4% and 79.8%, respectively. The mean radiographic index immediately after surgery and more than 6 months after the surgery for the control group was 73.4% and 76.7%, respectively (Wilcoxon signed rank test, P>0.05). The mean radiographic index increased 11.4% in the experimental group and 3.27% in the control group (Mann–Whitney U-test, P<0.05).

Conclusion

Based on the results, use of rhBMP-2/ACS on bone defect sites after sequestrectomy could be a successful strategy for treatment of MRONJ patients.

Autonomic and Psychologic Risk Factors for Development of Tinnitus in Patients with Chronic Temporomandibular Disorders

AIMS

To investigate the roles of autonomic regulation and psychologic condition in the development of tinnitus in patients with chronic temporomandibular disorders (TMD).

METHODS

In total, 55 participants (mean age 36.4 ± 12.6 years; 7 men, 48 women) were involved: 13 with no signs of painful TMD or tinnitus (CON), 15 with painful TMD without tinnitus (pTMD), and 27 with both painful TMD and tinnitus (TMDTIN). The Research Diagnostic Criteria for TMD and the Tinnitus Handicap Inventory (THI) were used to classify painful TMD and self-reported tinnitus, respectively. Measures of arterial heart rate (HR) and blood pressure (BP) were assessed at rest and in response to orthostatic challenges, cold-stress vasoconstriction, Valsalva maneuver, and psychologic stress. The sympathetic variables (BP responses to standing, cold stress, and psychologic stress) and parasympathetic variables (HR response to Valsalva maneuver [Valsalva ratio] and active standing [30:15 ratio]) were estimated.

RESULTS

Parasympathetic measures demonstrated significant differences between pTMD and TMDTIN. The period of pain duration showed significant positive correlations with BP variables during orthostatic challenges and/or cold stress in both pTMD and TMDTIN. THI scores showed significant positive correlations with results from the psychologic analysis. The range of motion of the mandible demonstrated a greater correlation with results from the psychologic analysis in TMDTIN compared to pTMD.

CONCLUSION

Dysregulated psychophysiologic interactions may affect the development of tinnitus in patients with chronic TMD.

Posterior maxillary segmental osteotomy for management of insufficient intermaxillary vertical space and intermolar width discrepancy: a case report

BACKGROUNDS

Insufficient intermaxillary space is caused by non-restoration following tooth extraction in the past, and this involves eruption of the opposing teeth and changes of the arch structure. Such cases are difficult just by a simple prosthetic approach, and diversified treatment plans should be established. Among these, posterior maxillary segmental osteotomy (PMSO) is an efficient treatment option than extraction of opposing teeth as it surgically repositions multiple erupted teeth and alveolar bone. PMSO can preserve the natural teeth; therefore, it is being regarded as a treatment method which can improve insufficient intermaxillary space significantly.

CASE PRESENTATION

In this case report, the first patient received PMSO in order to place an implant in the mandibular edentulous space after decreased vertical dimension is restored, and the second patient received PMSO along with orthodontic treatment to obtain the intermaxillary space and balance the interarch molar width.

CONCLUSION

PMSO is the treatment of choice when occlusion is compromised in the presence of decreased vertical dimension or arch length discrepancy.

Comparison of Diagnostic Performance Between Visual and Quantitative Assessment of Bone Scintigraphy Results in Patients With Painful Temporomandibular Disorder

This retrospective clinical study was performed to evaluate whether a visual or quantitative method is more valuable for assessing painful temporomandibular disorder (TMD) using bone scintigraphy results.In total, 230 patients (172 women and 58 men) with TMD were enrolled. All patients were questioned about their temporomandibular joint (TMJ) pain. Bone scintigraphic data were acquired in all patients, and images were analyzed by visual and quantitative methods using the TMJ-to-skull uptake ratio. The diagnostic performances of both bone scintigraphic assessment methods for painful TMD were compared.In total, 241 of 460 TMJs (52.4%) were finally diagnosed with painful TMD. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the visual analysis for diagnosing painful TMD were 62.8%, 59.6%, 58.6%, 63.8%, and 61.1%, respectively. The quantitative assessment showed the ability to diagnose painful TMD with a sensitivity of 58.8% and specificity of 69.3%. The diagnostic ability of the visual analysis for diagnosing painful TMD was not significantly different from that of the quantitative analysis.Visual bone scintigraphic analysis showed a diagnostic utility similar to that of quantitative assessment for the diagnosis of painful TMD.

Correlation between clinical symptoms and magnetic resonance imaging findings in patients with temporomandibular joint internal derangement

Objectives

The purpose of this study was to clarify which findings in magnetic resonance imaging (MRI) are good predicators of pain and mouth opening limitation in patients with temporomandibular joint (TMJ) internal derangement (ID).

Materials and Methods

Clinical examinations for pain and mouth opening limitation were conducted for suspected TMJ ID. MRI scans were taken within a week of clinical examinations. On the oblique-sagittal plane image, readings were obtained in terms of the functional aspect of disc position, degree of displacement, disc deformity, joint effusion, and osteoarthrosis. Multiple logistic regression analyses were conducted to identify the predictors of pain and mouth opening limitation.

Results

A total of 48 patients (96 TMJs) were studied, including 39 female patients and 9 male patients whose ages ranged from 10 to 65 years. The resultant data showed significant correlations between pain and the MR imaging of the degree of disc displacement (P<0.05). The probability of there being pain in moderate to significant cases was 9.69 times higher than in normal cases. No significant correlation was found between mouth opening limitation and MRI findings.

Conclusion

We identified a significant correlation between clinical symptoms and MRI findings of ID. The degree of anterior disc displacement may be useful for predicting pain in patients with TMJ ID.

Simultaneous Glossectomy with Orthognathic Surgery for Mandibular Prognathism

Macroglossia can create dental and skeletal instability after orthodontic treatment or orthognathic surgery for mandibular prognathism. In relevant literature, partial glossectomy is suggested for a good post-treatment prognosis. Most of the published partial glossectomy cases are two-staged surgery, because of concern about postoperative airway obstruction. As orthognathic surgical techniques and fixation method develop, however, concerns about postoperative airway obstruction have lessened. In this case, mandibular setback surgery and partial glossectomy were performed simultaneously, leading to stable recovery without any postoperative respiratory problems. After surgical technique to preserve the tongue tip, we achieved good outcomes without postoperative side effects of lingual hypoesthesia, pronunciation disorder and dyskinesia. We report this case with a literature review.

Anchor Plate Efficiency in Postoperative Orthodontic Treatment Following Orthognathic Surgery via Minimal Presurgical Orthodontic Treatment

Purpose:

The efficiency of an anchor plate placed during orthognathic surgery via minimal presurgical orthodontic treatment was evaluated by analyzing the mandibular relapse rate and dental changes.

Methods:

The subjects included nine patients with Class III malocclusion who had bilateral sagittal split osteotomy at the Division of Oral and Maxillofacial Surgery, Department of Dentistry in Ajou University Hospital, after minimal presurgical orthodontic treatment. During orthognathic surgery, anchor plates were placed at both maxillary buttresses. The anchor plates were used to move maxillary teeth backward and for maximum anchorage of Class III elastics to minimize mandibular relapse during the postoperative orthodontic treatment. The lateral cephalometric X-ray was taken preoperatively (T0), postoperatively (T1), and one year after the surgery (T2). Seven measurements (distance from Pogonion to line Nasion-Nasion perpendicular [Pog-N Per.], angle of line B point-Nasion and Nasion-Sella [SNB], angle of line maxilla 1 root-maxilla 1 crown and Nasion-Sella [U1 to SN], distance from maxilla 1 crown to line A point-Nasion [U1 to NA], overbite, overjet, and interincisal angle) were taken. Measurements at T0 to T1 and T1 to T2 were compared and differences tested by standard statistical methods.

Results:

The mean skeletal change was posterior movement by 13.87±4.95 mm based on pogonion from T0 to T1, and anterior movement by 1.54±2.18 mm from T1 to T2, showing relapse of about 10.2%. There were significant changes from T0 to T1 for both Pog-N Per. and SNB (P <0.05). However, there were no statistically significant changes from T1 to T2 for both Pog-N Per. and SNB. U1 to NA that represents the anterior-posterior changes of maxillary incisor did not differ from T0 to T1, yet there was a significant change from T1 to T2 (P <0.05).

Conclusion:

This study found that the anchor plate minimizes mandibular relapse and moves the maxillary teeth backward during the postoperative orthodontic treatment. Thus, we conclude that the anchor plate is clinically very useful.

Open reduction and internal fixation of mandibular fracture in an 11-month-old infant: a case report

Mandibular fractures in infants are rare. This case report describes management of a mandibular fracture in an 11-month-old infant using a microplate and screws with open reduction. The surgical treatment was successful. Because the bone fragments were displaced and only the primary incisors had erupted, conservative treatment, such as an acrylic splint and circummandibular wiring, was not recommended. Nine weeks after surgery, the microplate was removed. The results showed complete clinical and radiological bone healing with normal eruption of deciduous teeth.

Implant-supported overdenture with prefabricated bar attachment system in mandibular edentulous patient

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar® is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar® was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar® system in a mandibular edentulous patient.

The influence of etiology and treatment factors on intellectual outcome in congenital hypothyroidism

To determine the effects of hypothyroidism and hormonal patterns on outcome, we tested 65 7- to 12-year-old children with congenital hypothyroidism using standardized tests of intelligence, neuropsychological functioning, memory, and achievement. Results were analyzed by etiology, time to thyrotropin normalization, and hormone levels at testing. Children with athyreosis scored below other etiologies on visuospatial, attention, and arithmetic indices. Children whose thyroid-stimulating hormone levels normalized by 1 to 2 months of age scored higher than later normalizers on indices of visual memory, attention, and arithmetic. Normalization of thyroid-stimulating hormone by 3 months of age was associated with better memory and learning abilities than later normalization. Thyroid hormone levels at testing were correlated with indices of sensorimotor, spatial, and language abilities. Two children with persistently elevated thyrotropin levels were not adversely affected. Present findings signify the need to establish etiology, normalize thyrotropin early, and maintain hormone levels in the normal range throughout childhood in children with congenital hypothyroidism.

Analysis of expressed sequence tags from Brassica rapa L. ssp. pekinensis

Non-redundant expressed sequence tags (ESTs) were generated from six different organs at various developmental stages of Chinese cabbage, Brassica rapa L. ssp. pekinensis. Of the 1,295 ESTs, 915 (71%) showed significantly high homology in nucleotide or deduced amino acid sequences with other sequences deposited in databases, while 380 did not show similarity to any sequences. Briefly, 598 ESTs matched with proteins of identified biological function, 177 with hypothetical proteins or non-annotated Arabidopsis genome sequences, and 140 with other ESTs. About 82% of the top-scored matching sequences were from Arabidopsis or Brassica, but overall 558 (43%) ESTs matched with Arabidopsis ESTs at the nucleotide sequence level. This observation strongly supports the idea that gene-expression profiles of Chinese cabbage differ from that of Arabidopsis, despite their genome structures being similar to each other. Moreover, sequence analyses of 21 Brassica ESTs revealed that their primary structure is different from those of corresponding annotated sequences of Arabidopsis genes. Our data suggest that direct prediction of Brassica gene expression pattern based on the information from Arabidopsis genome research has some limitations. Thus, information obtained from the Brassica EST study is useful not only for understanding of unique developmental processes of the plant, but also for the study of Arabidopsis genome structure.

NTR1 encodes a floral nectary-specific gene in Brassica campestris L. ssp. pekinensis

We have characterized a gene specifically expressed in the floral nectaries of Brassica campestris L. ssp. pekinensis. Differential screening led to the isolation of a floral nectary-specific cDNA clone. Northern hybridization indicated that its mRNA transcript is 1450 nucleotides long and specific to the flower base. In situ hybridization and immunolocalization showed that its mRNA and protein are localized specifically to both the lateral and median nectaries of flowers. The cDNA codes for a 43.8 kDa polypeptide 392 amino acids long. The protein was named nectarin1 (NTR1) after floral nectary protein. NTR1 was located in the cytoplasm of nectariferous cells in the nectaries and was also observed in nuclei at a much lower level. The level of the transcript increases with flower development, especially during nectary development, but decreases abruptly with the opening of the flower. Genomic Southern blot analysis indicated that at least three copies of homologous genes were present in the genome of B. campestris, but that only a single copy was present in both Arabidopsis thaliana and Lycopersicon esculentum. The deduced amino acid sequence of NTR1 shows similarity to S-adenosyl-L-methionine:salicylic acid carboxyl methyltransferase of Clarkia breweri which is expressed mostly in petals. The function of the gene is speculated to be involved in the methylation of a plant secondary metabolite in the floral nectaries.

Satellite cereal yellow dwarf virus-RPV (satRPV) RNA requires a douXble hammerhead for self-cleavage and an alternative structure for replication

The 110 nt hammerhead ribozyme in the satellite RNA of cereal yellow dwarf virus-RPV (satRPV RNA) folds into an alternative conformation that inhibits self-cleavage. This alternative structure comprises a pseudoknot with base-pairing between loop (L1) and a single-stranded bulge (L2a), which are located in hammerhead stems I and II, respectively. Mutations that disrupt this base-pairing, or otherwise cause the ribozyme to more closely resemble a canonical hammerhead, greatly increase self-cleavage. In a more natural multimeric sequence context containing the full-length satRPV RNA and two copies of the hammerhead, wild-type RNA cleaves much more efficiently than in the 110 nt context. Mutations in the upstream hammerhead, including a knock-out in the catalytic core, affect cleavage at the downstream cleavage site, indicating that multimers of satRPV RNA cleave via a double hammerhead. The double hammerhead includes base-pairing between two copies of the L1 sequence which extends stem I. Disruption of L1-L1 base-pairing slows cleavage of the multimer. L1-L2a base-pairing is required for efficient replication of satRPV RNA in oat protoplasts. Mutations that affect self-cleavage of the multimer do not correlate with replication efficiency, indicating that the ability to self-cleave is not a primary determinant of replication. We present a replication model in which multimeric satRPV RNA folds into alternative conformations that cannot form in the monomer. One potential metastable intermediate conformation involves L1-L2a base-pairing that may facilitate formation of the double hammerhead. However, we conclude that L1-L2a also performs some other essential function in the satRPV RNA replication cycle, because the L1-L2a base-pairing is more important than efficient self-cleavage for replication.

Molecular characterization of the garlic virus X genome

The complete nucleotide sequence of the cDNA genome for garlic virus X (GVX), one of the major viruses infecting garlic plants, was determined. GVX is a single-stranded positive-sense RNA virus consisting of 8106 nucleotides excluding the 3'-end poly(A) tail and contains six open reading frames (ORFs) which encode putative proteins of 174 kDa (ORF1), 26 kDa (ORF2), 12 kDa (ORF3), 32 kDa (ORF4), 26 kDa (ORF5) and 15 kDa (ORF6). The putative viral proteins show similarity to those of carlaviruses and potexviruses but show the highest homology to shallot virus X (ShVX). Even though the GVX genome contains most of the structural elements common to carlaviruses and potexviruses, it is distinguished from them by the presence of an ORF4 which encodes an unusual protein. These results suggest that GVX may belong to an unassigned group of ShVX and GarV-type viruses rather than to the carlaviruses or potexviruses.

Identification of one of the major viruses infecting garlic plants, garlic virus X

A partial cDNA clone for garlic virus X (GVX) was isolated. GVX was identified immunologically with an antibody raised against the recombinant coat protein (CP) and demonstrated to be one of the major viruses infecting garlic plants showing mosaic or streak symptoms. GVX belongs to an unassigned group of ShVX and GarV-type viruses rather than to carlaviruses or potexviruses. The recombinant CP of GVX was purified by Ni(2+)-NTA affinity chromatography. Anti-GVX CP antibody was raised against the purified recombinant CP. GVX particle is flexuous, rod-shaped, and about 750 nm long as determined by immunoelectron microscopy. The extent of infection by GVX of garlic plants was analyzed by Northern or immunoblot analyses of individual garlic plants cultivated in different regions. These results showed that almost all of the garlic plants tested from 40 different regions including America, China, Japan, and Korea are infected with GVX.

The loop B domain is physically separable from the loop A domain in the hairpin ribozyme

In order to understand the catalysis mechanism of the hairpin ribozyme, mutant ribozymes were constructed. The distance between the loop A domain and the loop B domain was extended by inserting various lengths of nucleotide linkers at the hinge region in cis mutants, or the domains were separated physically in a trans mutant. All the mutant ribozymes, including the trans mutant, could cleave substrate RNA at the predicted site. A cis mutant with a single nucleotide insertion exhibited cleavage activity about twice as high as that of the wild-type (wt) ribozyme. The insertion of 2-5 nucleotides (nt) gradually reduced the activity to the level of the wt ribozyme. Insertion of a longer linker, up to 11 nt, resulted in the reduction of activity to one half of that of the wt ribozyme. The ribozyme with a single nucleotide insertion at the hinge region seems to form a more suitable conformation for catalysis by three-dimensional fold-back of the loop B to loop A containing the cleavage site. The trans mutant, in which the A and B domains were physically separated, maintained a significant level of activity, suggesting that both domains are necessary for catalysis, but separable. These results demonstrate that interaction between the A and B domains results in catalysis.