The 50 most cited articles on soft tissue integration of dental implants: A bibliometric analysis.

STATEMENT OF PROBLEM: Soft tissue integration helps prevent the bacterial invasion of dental implants, but bibliometric studies on the top 50 most cited articles in the field of soft tissue integration are lacking. PURPOSE: The purpose of this bibliometric study was to analyze the 50 most cited articles since 1999 to explore global trends and research hotspots. MATERIAL AND METHODS: A specific search strategy of the Science Citation Index Expanded (Web of Science) was devised, and relevant article-based, journal-based, and author-based parameters were analyzed. Correlation analysis was performed (α=.05). RESULTS: The number of citations ranged from 71 to 586. Clinical Oral Implants Research was the most cited journal (1722 citations). Berglundh, Tord was the author with the most publications (6 publications) and citations (957 citations). Dental implants and titanium were the keywords with the highest frequency. Switzerland was the country with the highest number of publications (12 publications). Correlation was found between the publication year and average annual citations (P<.001). CONCLUSIONS: This study determined the scientific progress in soft tissue integration. The surface design of dental implant materials is essential for the soft tissue integration of dental implants. Soft tissue integration has been a focus of interest in the past few years, but many experiments still need to be done to improve soft tissue compatibility with innovative materials.

Treatment effects after maxillary expansion using tooth-borne vs tissue-borne miniscrew-assisted rapid palatal expansion appliance.

INTRODUCTION: The study investigated the skeletal effects and root resorption in young adults with maxillary transverse deficiency after tissue-borne or tooth-borne mini-implant anchorage maxillary expansion. METHODS: Ninety-one young adults with maxillary transverse deficiency, aged 16-25 years, were divided into 3 groups according to the treatment method: group A (n = 29) comprising patients treated with tissue-borne miniscrew-assisted rapid palatal expansion (MARPE), the group B (n = 32) comprising patients treated with tooth-borne MARPE, and the control group (n = 30) comprising patients only treated with fixed orthodontic therapies. Pretreatment and posttreatment cone-beam computed tomography images were used to assess the change of maxillary width, nasal width, first molar torque and root volume by paired t test in the 3 groups, respectively. Analysis of variance and Tukey least significant difference analysis were used to detect the changes of all descriptions among the 3 groups P <0.05. RESULTS: In the 2 experimental groups, we observed significant increases in the width of the maxilla, nasal, and arch width, as well as the molar torque. In addition, the height of the alveolar bone and the root volume decreased significantly. There were no significant differences in the maxilla, nasal, and arch width change between the 2 groups. Group B displayed more increases in buccal tipping, alveolar bone loss, and root volume loss than group A (P <0.05). Compared with groups A and B, the control group showed negligible tooth volume loss, with no expansion effect in both skeletal and dental descriptions. CONCLUSIONS: Tissue-borne MARPE produced the same expansion efficiency as tooth-borne MARPE. However, tooth-borne MARPE causes more dentoalveolar side effects in buccal tipping, root resorption and alveolar bone loss.

Factors related to microimplant-assisted rapid palatal expansion in teenagers and young adults: A cone-beam computed tomography study.

INTRODUCTION: For patients with maxillary transverse deficiency, selecting an appropriate therapeutic method is important for the treatment effect and prognosis. Our study aimed to explore factors related to microimplant-assisted rapid palatal expansion (MARPE) in teenagers and young adults using cone-beam computed tomography. METHODS: Twenty-five patients who underwent MARPE were included in this retrospective study from February 2014 to June 2019. Midpalatal suture density (MPSD) ratio, midpalatal suture maturation (MPSM), bone effect, dentoalveolar effect, and dental effect in maxillary first molar were evaluated using cone-beam computed tomography. Spearman correlation analysis was used to analyze the correlation between the MPSD ratio, MPSM, age, and the expansion amount generated by MARPE. RESULTS: Twenty-five patients (mean age, 19.84 ± 3.96 years; range, 15-29 years) with maxillary transverse deficiency were analyzed. Age was negatively correlated with bone expansion, alveolar expansion, and alveolar change (all P <0.05). There was a negative correlation between MPSM and nasal cavity variation, bone expansion, and alveolar change (all P <0.05). The bone expansion was negatively correlated with MPSD ratio 3 (r = -0.417; P <0.05) and MPSD ratio 4 (all P <0.05). CONCLUSIONS: Age, MPSM, and MPSD ratio were significantly related to the MARPE effect. Age, MPSM, and MPSD ratio should be considered when choosing MARPE.

Obstructive sleep apnea: a follow-up program in its relation to temporomandibular joint disorder, sleep bruxism and orofacial pain.

OBJECTIVE: To evaluate the correlation between obstructive sleep apnea (OSA) and temporomandibular joint (TMJ) morphology, tooth wear condition, orofacial pain through a follow-up program. MATERIALS AND METHODS: Seventy one OSA patients were divided into three groups according to their (apnea hypopnea index) AHI: mild group (n = 23), moderate group (n = 24), and severe group (n = 24). All patients had OSA therapies around six months after confirm the diagnosis of OSA. The tooth wear score and orofacial pain condition of all patients were recorded via clinical examination. Cone beam computed tomography (CBCT) images were also taken when confirm the diagnosis of OSA (T0), 6 months after the diagnosis (T1), and 6 months after the OSA treatment (T2). Parameters indicating the condylar morphology and joint space were evaluated. The differences of clinical symptoms and TMJ conditions among T0, T1 and T2 time point were detected in the three groups respectively. The changes in T1-T0 and T2-T1 of all descriptions among three groups were also compared. The correlations between AHI and clinical symptoms were detected with Spearman correlation analysis. RESULTS: In mild group, there was no difference in all clinical symptoms and TMJ morphology among the three time points. Both in moderate and severe group, the condylar volume, superficial area, wear score, visual analogue scales (VAS), and R value (indicating condyle position) displayed significant differences among the three time points (P < 0.05). From T0 to T1, mild group displayed fewer decreases in the condylar volume and superficial area and fewer increases in wear score than that in moderate and severe group (P < 0.05). From T1 to T2, there was a greatest reduction in severe group for R value, and significant difference in the description of VAS and R value were found among the three groups. AHI was negatively correlated condylar volume and condylar superficial area, and was positively correlated with tooth wear score and VAS (P < 0.05). CONCLUSION: Moderate to severe OSA will aggravate orofacial pain and tooth wear, affect TMJ volume and superficial area, even change the location of condyles. Appropriate OSA therapies may be effective ways to alleviate these adverse effects in long-term.

Treatment effects after maxillary expansion using invisalign first system vs. acrylic splint expander in mixed dentition: a prospective cohort study.

BACKGROUND: Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What's more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors. MATERIALS AND METHODS: After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons. RESULTS: There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups. CONCLUSIONS: Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD. TRIAL REGISTRATION: This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

Morphological changes in alveolar bone thickness and height after orthodontic proclination or labial movement combined with autogenous soft tissue grafting: a CBCT evaluation.

BACKGROUND: Autogenous soft tissue grafting is indicated in thin gingival biotypes before orthodontic proclination or labial movements to increase the keratinized gingiva and prevent gingival recession. However, its effect on local alveolar bone remodeling is unclear. The aim of this study was to investigate the effects of autogenous soft tissue grafting on local alveolar bone after orthodontic proclination or labial movements. METHODS: Sixteen patients with a thin scalloped gingival biotype, narrow keratinized gingiva, or thin cortical bone requiring orthodontic proclination or labial movement of teeth were included. Cone-beam computed tomography (CBCT) images were obtained before grafting and at least 6 months after surgery. Sixty mandibular teeth were included, and the vertical bone level and horizontal labial bone thickness were measured. The results were compared using paired t-tests or Wilcoxon signed-rank test. RESULTS: The horizontal labial bone thickness increased, especially at 6 mm below the cementoenamel junction (CEJ) in the mandibular central and lateral incisors (P < 0.05). The total alveolar bone area of the canines, first premolars, and second premolars increased at 3, 6, and 9 mm below the CEJ, respectively, and the differences were statistically significant (P < 0.05). Additionally, vertical bone height increased minimally on the labial side, but the differences were not statistically significant (P > 0.05). CONCLUSIONS: New bone regeneration was observed on the labial (pressure) side after autogenous soft tissue grafting, which may represent a mechanism to effectively prevent gingival recession and maintain periodontal health. IRB APPROVAL: All the experimental procedures involving humans in this study were approved by the Medical Ethics Committee of Xiangya Stomatological Hospital, Central South University ( No. 20190048).

Effects of occlusal splint and exercise therapy, respectively, for the painful temporomandibular disorder in patients seeking for orthodontic treatment: a retrospective study.

OBJECTIVE: To evaluate the effect of hard stabilization splints (HSS), counselling and exercise therapies, respectively, for the painful temporomandibular disorder (TMD) in patients seeking for orthodontic treatment through magnetic resonance imaging (MRI) and clinical examination. MATERIALS AND METHODS: Eighty-seven TMD patients were divided into two groups according to their therapies: the HSS group (n = 43) comprising of patients treated with HSS, counselling and masticatory muscle exercises; the control group (n = 44) comprising of patients treated with counselling and masticatory muscle exercises alone. All patients had orthodontic therapies after the first treatment phase. The joint pain and clicking of all patients were recorded via clinical examination. MRIs of HSS groups were taken before (T0), after the first phase (T1), and after the orthodontic treatment (T2). Parameters indicating the condyles and articular discs were evaluated. Clinical symptom (pain and clicking) changes among T0, T1 and T2 time point were detected in the two groups respectively. The significant differences between HSS and control groups, as well as between male and female were tested at T1 and T2. Position changes of condyles and discs in HSS group among T0, T1 and T2 were detected in male and female respectively. RESULTS: After the first treatment phase, there was no difference in the decrease of facial pain between the two group, as well as between male and female in the two groups (P > 0.05). Clicking decreasing was not statistically significant. After the whole orthodontic periods, the TMJ pain relapsed in female of the control group, and the number of female's pain joints was more than male's (P < 0.05). In the HSS group, the posterosuperior movements of discs and the anteroposterior movements of condyles were recorded in closing position (P < 0.05). After the whole orthodontic periods, female's disc-condyle angles increased, the discs to HRP distance decreased and condyles to VRP distance increased when compared with the data of T1 (P < 0.05). CONCLUSIONS: For the orthodontic patients with painful TMD, HSS combined with counselling and exercise therapies before orthodontic treatment could provide pain relief. HSS is helpful to improve the position and relation of discs and condyles. In addition, male's prognosis is better than female's in terms of stability.

Displacement and stress distribution of the craniomaxillofacial complex under different surgical conditions: a three-dimensional finite element analysis of fracture mechanics.

OBJECTIVE: To provide a simplified treatment strategy for patients with maxillary transverse deficiency. We investigated and compared the fracture mechanics and stress distribution of a midline palatal suture under dynamic loads during surgically-assisted rapid palatal expansion. METHODS: Based on the cone-beam computed tomography (CBCT) data of a 21-year-old female volunteer, a three-dimensional model of the cranio-maxillofacial complex (including the palatal suture) was constructed. A finite element analysis model was constructed based on meshwork. After the yield strength of the palatal suture was set, an increasing expansion force (0-500 N) was applied within 140 ms to calculate the time-load curve, which mimicked nonsurgical bone expansion (model A). The same method was used to evaluate the fracture process, time and stress distribution of the palatal suture in maxillary lateral osteotomy-assisted (model B) and LeFort osteomy I (LFIO)-assisted expansion of the maxillary arch (model C). RESULTS: Compared with model A, the palatal suture of model B and model C showed a faster stress accumulation rate and shorter fracture time, and the fracture time of model B and model C was almost identical. Compared with model A, we discovered that model B and model C showed greater lateral extension of the maxilla, and the difference was reflected mainly in the lower part of the maxilla, and there was no difference between model B and model C in lateral extension of the maxilla. CONCLUSIONS: Compared with arch expansion using nonsurgical assistance (model A), arch expansion using maxillary lateral wall-osteotomy (model B) or LFIO had a faster rate of stress accumulation, shorter time of fracture of the palatal suture and increased lateral displacement of the maxilla. Compared with arch expansion using LFIO (model C), arch expansion using lateral osteotomy (model B) had a similar duration of palatal suture rupture and lateral maxillary extension. In view of the trauma and serious complications associated with LFIO, maxillary lateral wall-osteotomy could be considered a substitute for LFIO.

Effects of occlusion modification on the remodelling of degenerative mandibular condylar processes.

OBJECTIVE: The temporomandibular joint (TMJ) displays a high remodelling capability in response to occlusion changes. The purpose of the current study was to investigate the responses of TMJ condyles of growing mice to the installation of a unilateral anterior crossbite (UAC) prosthesis and the replacement of the UAC prothesis with a bilateral anterior elevation (BAE) prosthesis. MATERIALS AND METHODS: C57BL/6J mice were randomly assigned to the blank control and experimental groups. In mice in the experimental groups, UAC was created, while in others, BAE was created after the creation of UAC or removal of UAC. Changes in TMJ condylar cartilage and subchondral bone were assessed. RESULTS: The degradation of condylar cartilage induced by UAC was reversed by BAE, as evaluated by cartilage histochemical changes, collagen II-positive area, collagen X-positive chondrocytes and expression levels of Adamts-5, Mmp13, Tnf-α and Il-1ß. Subchondral bone was assessed based on the subchondral bone volume, the number of TRAP-positive cells and the Opg/Rankl ratio. CONCLUSION: The growing mouse TMJ condyle displays a high remodelling capability, which can be degenerative or rehabilitative in response to the creation of UAC and the replacement of UAC with BAE. Early correction of occlusion is beneficial for the recovery of degenerative condyles.

Changes of the upper airway and bone in microimplant-assisted rapid palatal expansion: A cone-beam computed tomography (CBCT) study.

OBJECTIVE: To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT). METHODS: This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes. RESULTS: After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05). CONCLUSIONS: MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

Analysis of Senescence-Related Differentiation Potentials and Gene Expression Profiles in Human Dental Pulp Stem Cells.

INTRODUCTION: Dental pulp stem cell (DPSC)-mediated dental pulp regeneration is considered a promising method for the treatment of deep caries with pulpitis. However, mesenchymal stem cell (MSC) senescence is an adverse factor from the perspective of cell-based therapies. In this study, we investigated the characteristics and expression profiles of DPSCs from young and old donors. METHODS: DPSCs from young and old donors were cultured in differentiation medium, and their differentiation potentials were assessed. Long noncoding RNA (LncRNA) microarray assays and a bioinformatic analysis were performed to investigate differences in LncRNA and mRNA expression profiles between DPSCs from young and old donors. RESULTS: We found that DPSCs from young donors exhibited more powerful proliferation ability and greater osteogenic and adipogenic differentiation potentials than DPSCs from old donors. In DPSCs from young donors, numerous LncRNAs were significantly up- (n = 389) or down-regulated (n = 172) compared to DPSCs from old donors. Furthermore, 304 mRNAs were differentially expressed, including 247 up-regulated genes and 57 down-regulated genes in DPSCs from young donors. The bioinformatic analysis identified that several pathways may be associated with DPSC characteristics, such as those involved in the cell cycle and RNA transport, and revealed nuclear transcription factor Y subunit ß, general transcription factor IIB, and nuclear receptor subfamily 3 group C member 1 as core regulatory factors and FR249114, FR299091, and ENST00000450004 as core LncRNAs. CONCLUSIONS: Our results indicated that senescence impaired the proliferation and differentiation potentials of DPSCs and that donor age is an important factor that affects their use for tooth regeneration. We also provide insight into the mechanisms responsible for senescence in DPSCs.

The role of rapid maxillary expansion in pediatric obstructive sleep apnea: Efficacy, mechanism and multidisciplinary collaboration.

This review aims to provide current knowledge about the efficacy, mechanism, and multidisciplinary collaboration of rapid maxillary expansion (RME) treatment in pediatric obstructive sleep apnea (OSA). OSA is a chronic disease characterized by progressively increasing upper airway resistance, with various symptoms and signs. Increasingly the evidence indicates that RME is a non-invasive and effective therapy option for children with OSA. Besides, the therapeutic mechanism of RME includes increasing upper airway volume, reducing nasal resistance, and changing tongue posture. Recent clinical researches and case reports also show that a multidisciplinary approach improves sleep-disordered breathing in children. Applied with adenotonsillectomy, mandibular advancement, continuous positive airway pressure, and comprehensive orthodontic treatment, RME can be more effective in recurrent or residual OSA.

[Efficiency of clear aligners in extrusion of posterior teeth evaluated by 3-dimensional model superimposition].

PURPOSE: To explore the efficiency of posterior teeth extrusion with clear aligners by 3-dimensional model superimposition, which provides a reference for the design of clinical programs. METHODS: We selected 24 patients with clear aligners whose posterior teeth were designed to extend more than 0.5 mm, and a total of 126 teeth were included. Digital models were obtained before and after treatment by intraoral scanning with iTero, named as "actual initial" and "achieved" digital models. Initial and final models from the ClinCheck, labeled as "virtual initial" and "predicted" models respectively. Initial, predicted, and achieved digital dental models were exported as stereolithography files and subsequently imported into Geomagic Studio. Extrusive measurements were made from the superimposition of the initial and predicted models (predicted movement) and from the superimposed initial and achieved models (achieved movement). Statistical analysis was performed with SPSS 23.0 and GraphPad Prism 5.0 software package. The extrusion efficiency of the posterior teeth was calculated, at the meanwhile the influencing factors were analyzed. RESULTS: The mean extrusion efficiency of posterior teeth during clear aligners treatment was 30.2%. The actual extrusion was linearly related to the expected(P<0.05), and the linear regression equation was y=0.305x-0.010. The difference between the actual and the predicted extrusion was positively correlated with the number of appliances(P<0.05), and also positively correlated with the predicted extrusion value(P<0.001). This difference was larger in low-angle patients than in patients with average angle (P<0.05). CONCLUSIONS: The extrusion rate of posterior teeth is relatively low during clear aligners treatment, and the average efficiency is 30.2%. Vertical growth pattern affects the extrusion efficiency. So more overcorrections can be designed for average angle patients.

Effectiveness of modifications to preadjusted appliance prescriptions based on racial dental characteristics assessed by the ABO Cast-Radiograph Evaluation: A propensity score matching study.

BACKGROUND: Because racial discrepancies in dental characteristics are known to exist, designing preadjusted appliances according to racial normal occlusion data would be expected to improve treatment results. However, whether modifications based on racial characteristics can improve treatment outcomes in the clinic remains to be investigated. METHODS: To study the influence of prescription type on treatment outcomes, 91 patients treated with Chinese or Roth prescription appliances were selected as an initial sample. Two groups of patients were selected by propensity score matching (1:1) to limit the effects of confounding factors, including age, sex, case complexity, and extraction plan. Discrepancy Index and cervical vertebral maturation values were used to quantify case complexity and patient age, respectively. After matching, the final sample of 60 patients consisted of two groups of 30 patients each: group 1 had been treated with a Chinese prescription appliance and group 2 had been treated with a Roth prescription appliance. ABO casts and radiograph evaluation (CR-Eval) and lateral cephalograms were utilized to compare the treatment outcomes of the two groups. RESULTS: The total ABO scores of groups 1 and 2 were 22.03 and 23.87, respectively. There were no significant differences between the two groups in total ABO score or in seven other sub-scores; however, there was a significant difference between the two groups in mandibular canine alignment score. CONCLUSIONS: There are no significant differences in overall treatment outcomes between the Chinese and Roth prescription appliances. The Chinese prescription yielded better alignment results in the mandibular canine for Chinese patients.

Splice receptor-site mutation c.697-2A>G of the COL1A1 gene in a Chinese family with osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a genetic disorder characterized by bone fragility and blue sclerae, which are mainly caused by a mutation of the COL1A1 or COL1A2 genes that encode type I procollagen. Mutations in the splice site of type I collagen genes are one of the mutations that cause OI and usually lead to a mild or moderate OI phenotype. A heterozygous A to G point mutation in intron 9 at the -2 position of the splice receptor site of COL1A1 was identified in a family with type I or IV OI. Three affected individuals in four generations of one family all presented with several clinical symptoms. They all had pectus carinatum, flat feet, gray-blue sclerae, and normal stature, teeth, hearing, and vision. Forearm fractures, small joint dislocations, and muscle weakness were all present in the patient's father and grandmother, who presented with a moderate type IV phenotype. The 10-year-old proband with type I OI had suffered a fracture twice, but had no history of joint dislocation or skin hyperextensibility. Charting the family helped to identify clinical symptoms in patients with mutations at the N-terminal of type I collagen genes.

[Cone-beam CT study of the characteristics of midpalatal suture at different age groups in a southern China population].

PURPOSE: The purpose of this cone-beam CT (CBCT) based study was to investigate the stages of palatal suture at different age groups as well as the bone density of the palatal suture in a south Chinese population. METHODS: The CBCT data of 113 patients with an age range from 4 to 36 years old were selected. All of them were reported to have normal growth. CBCT image data were selected in accordance with the inclusion criteria. By using Angelieri method, the palate was divided into 5 groups, and Chad Evans Larson bone density ratio was calculated for each patient. One-way ANOVA and LSD analysis were used to evaluate the average bone density ratio of the mid-palatal at each age stage as well as the mean value of palatal suture bone density at different stages with SPSS 22.0 software package. RESULTS: By comparing the density ratio of mid-palatal suture for each age group, no significant difference was noticed for the same stage regardless of the age (stage B, C and D) (P＞0.05), significant difference was noticed between C and D(P＜0.05),no significant difference was noticed for the suture density between group A and B as well as group C and D (P＞0.05), significant difference was found for the suture density between A/C, A/D, A/E, B/C, B/D, B/E, C/D, and C/E groups(P＜0.05). CONCLUSIONS: The mid-palatal suture density in children under 15 years may belong to stage A, B or C , which is significantly lower than group D and E; Patients of a palatal stage C stay within an age range from 11 to 18. No inner group difference is noticed inside group C. The average suture density of group C is significantly larger than group A and B, whereas smaller than group D and E. The results showed that CBCT can be a useful tool to guide rapid mid-palatal expansion in clinical practice. Patients who have a lower density mid-palatal suture can be expanded.

[MBT straight wire for Class II division I malocclusion cases].

OBJECTIVE: To evaluate the therapeutic effects of MBT straight wire on extraction case of Class II division I. METHODS: Thirty-six class II division I malocclusion patients were treated with MBT straight wire by extracting 4 bicuspid premolars or 2 maxillary bicuspid premolars. The X-ray cephalograms were analyzed before and after the treatment of MBT straight wire. RESULTS: After the treatment, the overjet was reduced by 6.04 mm (P < 0.01); U1-NA was reduced by 15.43 degrees (P <0.01); and U1-NA (mm) was reduced by 4.71 mm (P <0.01). ANB was significantly reduced (P < 0.05). CONCLUSION: MBT straight wire not only shortens the operation but also shows superior effect for Class II division I malocclusion cases.

Heterozygous mutation of c.3521C>T in COL1A1 may cause mild osteogenesis imperfecta/Ehlers-Danlos syndrome in a Chinese family.

Osteogenesis imperfecta (OI) is an inheritable connective tissue disorder with a broad clinical heterozygosis, which can be complicated by other connective tissue disorders like Ehlers-Danlos syndrome (EDS). OI/EDS are rarely documented. Most OI/EDS mutations are located in the N-anchor region of type I procollagen and predominated by glycine substitution. We identified a c.3521C>T (p.A1174V) heterozygous mutation in COL1A1 gene in a four-generation pedigree with proposed mild OI/EDS phenotype. The affected individuals had blue sclera and dentinogenesis imperfecta (DI) was uniformly absent. The OI phenotype varied from mild to moderate, with the absence of scoliosis and increased skin extensibility. Easy bruising, joint dislocations and high Beighton score were present in some affected individuals. EDS phenotype is either mild or unremarkable in some individuals. The mutation is poorly conserved and in silico prediction support the relatively mild phenotype. The molecular mechanisms of the mutation that leads to the possible OI/EDS phenotype should be further identified by biochemical analysis of N-propeptide processing and steady state collagen analysis.

A rare case of osteogenesis imperfecta combined with complete tooth loss.

Osteogenesis imperfecta (OI) is a heritable disorder of the connective tissue characterized by blue sclerae, osteoporosis and bone fragility. Dentinogenesis imperfecta type I is commonly seen in OI patients, but other dental impairments, such as tooth agenesis or complete tooth loss, are rarely reported for these patients. Here, we report the case of a 37-year-old female Chinese OI patient who experienced complete tooth loss before puberty. The patient has a family history of OI and her father has a history of tooth loss. She showed obvious OI phenotypes, including a dwarfed stature, blue sclerae, scoliosis, pigeon chest and a history of fractures. Tooth loss began at the age of 6 years and continued until complete tooth loss at 20 years; this occurred in the absence of dental decay, gum disease, accidents or drug usage. Radiological studies revealed osteoporosis of the lower limbs and an underdeveloped scapula. Type I collagen gene analysis identified a known c.2314G>A (p.Gly772Ser) substitution in the COL1A2 gene, which we suggest affects the interaction between type I collagen and extracellular matrix proteins, including cartilage oligomeric matrix protein, phosphophoryn and SPARC (secreted protein acidic and rich in cysteine). In silico prediction indicated a relatively mild effect of the mutation, so it is conceivable that the severity of the clinical phenotype may result from additional mutations in candidate genes responsible for abnormal dental phenotypes in this family. To our knowledge, this is the first report of an OI patient with a phenotype of complete tooth loss at a young age.

[A preliminary study on the functional occlusion characters of the patients who had essential root resorption in anterior teeth].

PURPOSE: In order to determine the effect of functional occlusion on the essential root resorption, we compared the characters of functional occlusion between the patients who had essential root resorption in anterior teeth and who didn't have. METHODS: Panoramic radiography, periapical films and clinical data were used to diagnose the essential root resorption before the patients received orthodontic treatment. Fifteen patients who had 2-3 degree root resorption were divided into the experimental group, while 15 patients who didn't have were chosen as control group according to their age and sex. The functional occlusion of the cases in the experimental group and control group was checked on Denar Mark II articulator and via clinical examination, and the indexes of functional occlusion during protrusive and lateral movement in two groups were recorded. SPSS 13.0 software package was used for statistical analysis. RESULTS: The results showed that the number of anterior teeth occlusal interferences during lateral movement in the experimental group was more than that in control group by clinical (P<0.05) or articulator examination (P<0.05), but the number of posterior teeth occlusal interferences didn't have significant difference between the two groups. There was no significant difference in the retrusive range (RCP-ICP) in vertical, anterior-posterior and lateral direction respectively. CONCLUSION: It is suggested that as a kind of long-standing and minor trauma, the anterior teeth occlusal interferences during lateral movement might be a cause of essential root resorption in anterior teeth.