Buccal Side Research Articles

Histologic and histomorphometric evaluation of minicono abutment on implant surrounding tissue healing and bone resorption on implants placed in healed bone. An experimental study in dogs

<abstract> <p>The objective of this evaluation was to measure the width and length of connective tissue (CT) and crestal bone resorption (CBR) related to minicono® abutment inserted in conical connection dental implants, which were placed crestal and subcrestally in a dog's mandible.</p> <sec> <title>Materials and Methods</title> <p>Forty-eight Top DM implants with the same coronal diameter were placed at the crestal level, 1 mm (test 1 group) and 2 mm (test 2 group) positions underneath buccal-lingual bone crests. Dental implants used in the study were separated into three groups of 16 implants each. The implants were randomly inserted into healed bone after two months post-extraction sockets of three lower premolars, and first molar, bilaterally in six male fox hound dogs. One 3 mm minicono height abutment was connected to conical connection implants placed at the crestal level (control), 1 mm (test 1) and 2 mm (test 2) positions under buccal-lingual crests.</p> </sec><sec> <title>Results</title> <p>All abutments and implants used were clinically and histologically integrated into the bone-soft tissue. Soft tissue behavior was observed at eight and 12 weeks in all test groups, displaying similar quantitative findings with significant differences (p > 0.05). However, crestal bone loss was significantly greater at the buccal side around that control group compared to the test 1 and 2 groups. The difference values between groups at the implant shoulder to the top of the lingual bone crest (IS-LBC) and the implant shoulder to the top of the buccal bone crest (IS-BBC) were significantly greater for the test 2 group in comparison with the other two groups (p < 0.05) at eight weeks. In addition, crestal bone resorption (CBR) increased in the crestal group at twelve weeks, but it was reduced for the test 1 and test 2 groups in implants placed sub-crestally (p < 0.05).</p> </sec><sec> <title>Conclusions</title> <p>Crestal bone loss could be reduced using a 3 mm high abutment on implants submerged below the bone crest from 1 to 2 mm positions.</p> </sec></abstract>

Reattachment of Fractured Tooth Fragment by Multidisciplinary Treatment Approach.

Dental anterior fractures are common injuries, especially in those who practice extreme sports. This report describes a 25-year-old Bolivian patient who attended our private dental clinic in La Paz, Bolivia after experiencing an accident during downhill mountain biking. An intraoral examination revealed a fracture line on the buccal side in the middle third of the coronal portion of the right central maxillary incisor which extended towards the proximal and lingual sides. Multidisciplinary treatment, including crown lengthening, osteotomy, root canal treatment, fiberglass post insertion, and reattachment of the fracture segment was performed. A follow-up examination at 10 months later revealed that the tooth was completely reestablished both functionally and esthetically and that there was no periapical pathosis or discomfort. This outcome suggests that if a patient seeks a dental consultation soon after a complex crown-root fracture has occurred, and if the broken tooth segment is available, then reattachment offers an economical and simple treatment option which will allow immediate restoration of functionality and esthetic standards. Continued follow-up should form part of such a treatment plan to allow long-term pulp vitality and periodontal health status to be monitored.

History of frenectomy

The frenulum of the mouth is the mucous membrane of the mouth that joins the ventral side of the tongue, limiting its movements within a specific space; the frenulum labii superioris and the frenulum labii inferioris on the buccal side of the upper and lower lips, connect the cheeks to the fixed gingiva in the midline between the incisors. Their primary function is stabilizing the upper and lower lip and the tongue. Frenectomy is a surgical procedure to provide additional freedom of movement to the lip and tongue.

Posterior superior alveolar nerve block alone in the extraction of upper third molars: a prospective clinical study.

Third molar extraction is the most commonly performed minor oral surgical procedure in outpatient settings and requires regional anesthesia for pain control. Extraction of the maxillary molars commonly requires both posterior superior alveolar nerve block (PSANB) and greater palatine nerve block (GPNB), depending on the nerve innervations of the subject teeth. We aimed to study the effectiveness of PSANB alone in maxillary third molar (MTM) extraction. A sample size comprising 100 erupted and semi-erupted MTM was selected and subjected to study for extraction. Under strict aseptic conditions, the patients were subjected to the classical local anesthesia technique of PSANB alone with 2% lignocaine hydrochloride and adrenaline 1:80,000. After a latency period of 10 min, objective assessment of the buccal and palatal mucosa was performed. A numerical rating scale and visual analog scale were used. In the post-latency period of 10 min, the depth of anesthesia obtained in our sample on the buccal side extended from the maxillary tuberosity posteriorly to the mesial of the first premolar (15%), second premolar (41%), and first molar (44%). This inferred that anesthesia was effectively high until the first molars and was less effective further anteriorly due to nerve innervation. The depth of anesthesia on the palatal aspect was up to the first molar (33%), second molar (67%), and lateromedially; 6% of the patients received anesthesia only to the alveolar region, whereas 66% received up to 1.5 cm to the mid-palatal raphe. In 5% of the cases, regional anesthesia was re-administered. An additional 1.8 ml PSANB was required in four patients, and another patient was administered a GPNB in addition to the PSANB during the time of extraction and elevation. The results of our study emphasize that PSANB alone is sufficient for the extraction of MTM in most cases, thereby obviating the need for poorly tolerated palatal injections.

Effects of mouthguard and paste containing S-PRG filler on remineralization of artificial subsurface carious lesions

The aim of this in vitro study was to evaluate the remineralization effects of ethylene-vinyl acetate (EVA) sheet (sample; SHOFU) and paste (PRG Pro-Care Gel®; SHOFU) containing surface pre-reacted glass-ionomer (S-PRG) filler. Extracted human premolars were decalcified to create subsurface carious lesions on the buccal side. Decalcified tooth specimens were then covered by EVA sheets with two different S-PRG filler contents either with application of paste (PRG MG-Paste and EVA MG-Paste groups) or without application of paste (PRG MG and EVA MG groups), then immersed in a remineralization solution. Control group teeth were not covered with any mouthguard and did not receive application of paste. Micro-CT (μCT) images of the teeth before and after the remineralization process were obtained to compare mineral gains. The percentage remineralization (%R) of each group was calculated using the mineral density (MD) profile from μCT. The microstructure of the tooth surface was observed under scanning electron microscopy, and constituent elements were examined using an electron probe micro-analyzer. The PRG MG group showed a significantly higher %R than the Control or EVA MG groups. The PRG MG-Paste group showed a significantly higher %R than the PRG MG group. In the PRG MG-Paste group, small precipitations were observed on tooth surface, and silica and aluminum were detected. The combination use of S-PRG filler containing EVA sheet and PRG Pro-Care Gel exhibits a synergetic effect on remineralization of pre-cavitation carious lesions.

3D Finite Element Study of the Physiological Anchorage Control Concept on Anchorage Molars in Lingual Orthodontics.

To study the effect of the physiological anchorage control concept on anchorage molars in lingual and labial orthodontic techniques. Three-dimensional finite element models, including the right maxillary first molar, periodontal ligament, alveolar bone, and buccal tube, were established. The models were divided into the McLaughlin-Bennett-Trevisi (MBT™) straight-wire model with 0-degree maxillary first molar axial inclination and the physiologic anchorage Speewire system (PASS) model with -7-degree maxillary first molar axial inclination. Simulated sliding retraction forces (1 N, 1.5 N, and 2 N) were loaded on the buccal side and lingual side, and retraction forces (0.5 N, 0.75 N, and 1 N) were loaded on the buccal and lingual sides simultaneously. The displacements, principal stresses, and von Mises stresses of the periodontal ligament under different conditions were derived. The anchorage molars showed different degrees of rotation, tipping, intrusion, and extrusion. As the force increased, these displacement trends also increased. The mesial displacement of the buccal + lingual force loading was less than that of the other two groups. Under the same force load method, the mesial displacement of the PASS group was less than that of the MBT group. Tilt movement increases the tensile stress of the distal cervical margin and root mesial apical third and the compressive stress of the mesial cervical margin and root distal apical third. The maximum stress of the periodontal ligament was less than that of the other two groups when the lingual force was loaded. The physiological anchorage control concept in lingual orthodontics provides better sagittal anchorage control than in labial orthodontics, but there is no significant difference numerically. Attention should be given to the control of torsion, torque, and arch width. Tilt movement increases the PDL stress of the cervical margin and root apical third. The sliding retraction force should be loaded lingually to maintain the force value of 1∼1.5 N.

Three-dimensional mathematical analysis of the maximum stresses of the dentoalveolar segment under vertical and oblique loads

Functional overload of teeth and implants is one of the most important reasons for their loosening and removal. Predicting the overload of teeth and implants is possible using digital technologies and special programs. Each study requires a basic study of functional stress indicators in an identical (preferably three-dimensional) mathematical model, as close as possible to clinical conditions.
 The aim of the study was to study the maximum stresses in the hard tissues of the tooth and in the alveolar socket under vertical and inclined functional loads using three-dimensional mathematical modeling.
 A differentiated analysis of the maximum integral stresses in a single-rooted tooth (mandibular canine) and the surrounding alveolar segment: enamel, dentin, cementum, cortical bone, spongy bone was carried out. A three-dimensional mathematical model of the segment was created, in which the fabrics corresponded to natural ones in their properties. A load of 150 N was applied to the cutting edge of the tooth in the vertical direction and at an angle of 45° from the buccal side. The maximum integral stresses according to Mises were analyzed.
 According to the results of three-dimensional mathematical modeling in the hard tissues of the tooth, the maximum stresses under vertical and inclined loads are most significant in magnitude in enamel, then in dentin and in cement (with an inclined load, respectively, up to 77.610 MPa, 56.469 MPa, 15.832 MPa). An oblique load significantly increases the stresses in the hard tissues of the tooth and the surrounding bone compared to a vertical load (by 77.4% in the case of enamel). With a vertical load, the zones of maximum stresses in enamel and dentin are localized in the zone of the cutting edge, in cement – in the cervical and apical parts of the root; oblique load concentrates stresses in the cervical part of the tooth and the upper third of the root.
 Stresses in the cortical bone tissue in the vertical direction of the load of the tooth are distributed along the tooth hole and along the outer surface of the jaw at the transition to the basal margin; with an oblique direction of the load, the stresses in the cortical bone are concentrated in the region of the neck of the tooth; maximum stresses under vertical and inclined loads 5.066 MPa and 27.909 MPa. Stresses in spongy bone tissue are recorded under the zones of maximum stresses in the adjacent cortical bone; maximum stresses under vertical and inclined loads 1.382 MPa and 4.375 MPa.

Evaluation of Cortical Bone Thickness of Posterior Implant Sites Using CBCT in Iraqi Population.

Background Cortical bone thickness (CBT) is a critical factor for implant success and for determining the long-term dental implant treatment outcome. Objectives The objective of this investigation was to examine posterior cortical bone thickness buccally and lingually in dentate and edentulous implant sites according to gender. Materials and Methods CBT of 160 patients requiring a single posterior tooth implant was investigated by CBCT. The study included 80 males and 80 females. CBT was measured for implant edentulous sites at 3 levels including crestal bone (level 1), five mm from the crest (level 2), and ten mm from the crest (level 3). CBT was also measured for dentate sites at 3 levels including crestal bone (level 1), midroot bone (level 2), and apical portion (level 3). The differences of bone thickness between the levels of dentate sites were statistically analyzed using a Kruskal–Wallis one-way analysis of variance. Mann–Whitney test was used to determine the specific differences between group members. For the edentulous site, a one-way ANOVA was used. Results CBT increased gradually from the crestal level to the apical level in all groups (buccal and lingual side, male and female). However, CBT at lingual side was statistically higher than that at buccal side in all groups. The mean value of CBT was significantly higher in males than females for both edentulous and dentate site. The dentate site shows a higher CBT in the apical level than the edentulous group in both male and female/buccal and lingual groups. Conclusion CBT at the coronal levels is low and susceptible for resorption compared to the apical portion, especially for the female group. Moreover, CBT is thicker in males than females. It is essential to measure the CBT before making a treatment plan with dental implant prosthesis.

Effect of maxillary molar intrusion on surrounding bone density during treatment of anterior open bite

The aim of the current work is to estimate the impact of posterior maxillary intrusion on the surrounding bone intensity during correction of anterior open bite (AOB). The sample was 14 patients suffering from mild to moderate (3-5mm) anterior open bite with increased posterior maxillary vertical height. This study sample was allocated into two groups according to the corticotomy the approach. Buccal miniplates and palatal mini screws were used as skeletal anchorage for maxillary molars’ intrusion. The density of the alveolar bone related to right and left maxillary first permanent molars were measured 4.5 months after intrusion commencement. The study revealed that the alveolar bone density of right and left first permanent molars had statistically significant decreases. In the right side, buccal and palatal cortical density had statistically significant decrease, however it was non significant for left both cortical bone. Absolute molar intrusion could be attained by skeletal anchorage miniplates and mini screws in patients with frontal open bite malocclusion. The variation of bone intensity between buccal and palatal sides may account for the variance bone thickness changes after intrusion from the buccal to the palatal sides.

The Retention Effect of Resin-Based Desensitizing Agents on Hypersensitivity-A Randomized Controlled Trial.

Recently, the development of dental materials has increased the availability of various hyperesthesia desensitizers. However, there are no studies on the duration of retreatment in terms of adherence rates. Thus, the adhesion rates of resin-based desensitizers were investigated. We used a conventional desensitizer and a recently developed desensitizer containing calcium salt of 4-methacryloxyethyl trimellitic acid (C-MET) and 10-methacryloyloxydecyl dihydrogen calcium phosphate (MDCP). These colored agents were applied to the surfaces of premolars and molars, and the area was measured from weekly oral photographs. Areas were statistically analyzed and mean values were calculated using 95% confidence intervals. A p-value of <0.05 was considered statistically significant. These rates were significantly higher on the buccal side of the maxilla and lower on the lingual side of the maxilla. In addition, the desensitizer containing C-MET and MDCP displayed significantly higher adhesion rates. It is suggested that this will require monthly follow-ups and reevaluation because both agents cause less than 10% adherence and there is almost no sealing effect after 4 weeks. In addition, the significantly higher adhesion rate of the desensitizer containing C-MET and MDCP indicated that the novel monomer contributed to the improvement in the adhesion ability.

Effect of implant scan body geometric modifications on the trueness and scanning time of complete arch intraoral implant digital scans: An in vitro study

Statement of problemThe effect of the surface geometry of implant scan bodies (ISBs) on the accuracy and scanning time of complete arch implant digital scans remains uncertain. PurposeThe purpose of this in vitro study was to evaluate whether geometric modifications on implant scan bodies (nonmodified, subtractively modified, and additively modified ISBs) affect the trueness and scanning time of complete arch intraoral implant digital scans. Material and methodsA completely edentulous maxillary cast with 2 anterior parallel and two 17-degree posteriorly tilted implant abutment analogs was prepared. A digitized reference was created from this cast with polyetheretherketone (PEEK) (CARES Mono Scanbody for screw-retained abutment) ISBs by using a desktop scanner (E3). Three different groups were created: nonmodified (NM group), subtractively modified (SM group), and additively modified (AM group). For the NM group, no modifications were made to the ISBs. For the SM group, 4 round-shaped grooves were created on the buccal, lingual, mesial, and distal sides. For the AM group, PEEK beads were printed and cemented on the same areas of the ISB of the SM group. Fifteen consecutive scans were captured with an intraoral scanner (TRIOS 3) for each group, and the scanning time was recorded. By using a metrology software program, scans of each group were superimposed on the reference file to determine the 3D surface, linear, and angular position discrepancies of each ISB. Repeated-measures analyses of variance followed by univariate analysis and Bonferroni multiple comparison tests were performed to analyze the data (α=.05). To compare the mean time among groups, 1-way analysis of variance was performed followed by the Tukey post hoc tests. ResultsSignificant 3D surface, linear, and angular position discrepancies were found when measuring trueness among the NM, SM, and AM groups (P<.001). Discrepancies in 3D surface deviation were highest for the AM group (0.266 ±0.030 mm), and the lowest mean angular deviation values were for the SM group (0.993 ±0.062 degrees). However, the mean scanning time was not significantly different among the groups tested (P=.237). ConclusionsFor complete arch intraoral implant digital scans, subtractive modifications on ISBs enhanced scanning trueness, while additive modifications on ISBs decreased scanning trueness. However, implant scan body geometric modifications did not affect scanning time.

The Hammock Proposal: A Modification of Loma Linda Pouch Technique

Introduction: A technique, the "Loma Linda pouch," is introduced for repairing the perforated maxillary sinus membrane during sinus grafting procedures. The collagen membrane is then folded along the lateral access window to form a pouch that surrounds and isolates the graft material. In this review, we planned to devise a modification to the “Loma Linda pouch technique”. This ‘‘hammock’’ approach immobilizes the collagen membrane as far as possible, promotes greater blood supply, thereby increasing vital bone formation. Case presentation: When perforation occurs during elevation of the Schneiderian membrane, elevation of the membrane from the internal sinus walls must be completed. In this approach, plasma rich in growth factors is used as a graft carrier to achieve a more compact and homogeneous bone graft and to avoid particle dispersion. The rest of the procedure follows the classic sinus augmentation approach. Discussion: Ranges of techniques involve repairing perforations that range in size from 2 mm to 1.5 cm. For larger perforations (≥1.5mm), the only reported possibility is the use of a resorbable collagen membrane. Displacement of the collagen membrane is one of the most frequent complications. For this reason, perfect immobilization of the membrane is the key to success. Compared with other methods, this modified approach enhances the fixation of the collagen membrane not only on the buccal side but also on the palatal side of the sinus cavity. Conclusion: This technique achieves stable immobilization of the collagen membrane and, with it, better treatment predictability in future.

CBCT based assessment of crestal bone loss in patients treated with mandibular implant over dentures

Aim: The exclusive aim of this study was to assess of crestal bone loss in patients treated with mandibular implant over dentures. Authors utilized three dimensional diagnostic tool i.e. cone beam computed tomography (CBCT) for the study. Materials &amp; Methods: The study was conducted in the department of Prosthodontics of the institute wherein systematic sampling procedure was done to select completely edentulous patients. Complete dentures were fabricated with standard manner with compression moulding technique and heat cure acrylic resin. Cone beam computed tomography was completed to assess the bone quality and quantity at desired locations. Total 6 male and 6 female patients were included in the study. Group I has the implants of the right side of the mandible and Group II has implant placed on the left side of the mandible. The twenty four implants were studied in detail for bone losses in post operative phases. at mesial, distal, buccal and lingual sides of the dental implants. P value less than 0.05 was considered significant (p&lt; 0.05). Statistical Analysis and Results: Statistical analysis was completed by statistical software Statistical Package for the Social Sciences (SPSS).

Repositioning of the bone window in lateral sinus floor elevation with simultaneous implant placement: Aretrospective radiographic study.

To retrospectively evaluate whether repositioning the bone window leads to a better outcome of three-dimensional sinus augmentation in lateral sinus floor elevation (LSFE) with simultaneous implant placement. 34 patients with a total of 40 implants (14: test group, 26: control group) receiving LSFE with simultaneous implant placement were included in this retrospective research. CBCT images were taken before surgery, immediately and 6months after surgery. The two-dimensional augmentation parameters, including apical bone height (ABH), endo-sinus bone gain (ESBG), and palatal/buccal bone height (PBH/BBH), and three-dimensional parameters, including augmentation volume (AV) and palatal/buccal augmentation volume (PAV/BAV), were measured. The lateral defect length (LDL) and lateral window length (LWL) were also measured to evaluate the lateral antrostomy recovery. At the 6-month follow-up, the reduction rates at ABH, ESBG, and BBH of the test group (ABH: 10.41% ± 30.30%, ESBG: 2.55% ± 8.91%, BBH: 2.50% ± 8.65%) were significantly lower than those of the control group (ABH: 25.10% ± 22.02%, ESBG: 11.47% ± 9.79%, BBH: 7.10% ± 5.37%; p< .05). In addition, the test group showed better three-dimensional augmentation stability on the buccal side (BAV reduction: 15.51% ± 10.86% vs. 27.15% ± 12.61%; p< .05). Moreover, the LDL/LWL ratio of the test group was significantly lower than that of the control group (p< .05). Within the limitations of this study, repositioning of the bone window in LSFE with simultaneous implant placement could contribute to endo-sinus augmentation stability on the buccal side at the 6-month follow-up. Moreover, it would also facilitate recovery of the lateral antrostomy defect.

Assessment of commercially available bone graft material in the implant placed socket to enhance the osteointegration

Background: Alveolar bone resorption occurs in the majority of patients following teeth extraction. The present study was conducted to assess commercially available bone graft material in the implant placed socket to enhance the osteointegration. Materials &amp; Methods: The present study comprised of 64 patients of both genders. Concentrated growth factor (CGF) was prepared according to Sacco’s protocol, using the patients’ own venous blood. Extraction of mandibular first molars was carried out and implants were immediately placed with CGF grafting. A Cone Beam Computed Tomography (CBCT) was taken immediately after implant placement and after six months of undisturbed healing to assess the quantity and quality of new bone formed around implants. Results: Out of 64 patients, males were 40 and females were 24. The mean bone height was on buccal side immediately was 9.04 and after 6 months was 11.3, on lingual side immediately was 10.6 and after 6 months was 11.8, on distal side immediately was 8.3 and after 6 months was 11.0, on mesial side immediately was 7.5 and after 6 months was 11.2. The difference was significant (P&lt; 0.05).

Orthodontic Treatment and Central Incisors: a Study by CBCT Analysis

To determine potential risks and critical orthodontic movements of central incisors. CBCT analysis of 66 patients (aged 12-38 years; 30 adolescents and 36 adults; 33 males and 33 females). We evaluated alveolar bones (crests, plates, ridges) surrounding central incisors from buccal and lingual sides, and at multiple levels using the "Ez3D-plus" program with regard to buccolingual inclination and effective length of premaxilla/length of the mental protuberance. We identified: - Potential risks in the maxilla, in case of 1) Proclined central incisors, on the first buccal coronal third and lingual side of alveolar bone. 2) ELP < 13 mm, with buccal movement. - Potential risks in mandible, in case of 1) Retroclined central incisors, on the first lingual coronal third and buccal apical two-thirds of alveolar bone. 2) LMP > 9 mm. - Critical orthodontic movements: 1) Buccal tipping of mandibular central incisors is more critical in adolescents. 2) Lingual tipping of mandibular central incisors is more critical than of maxillary ones in all groups, at the level of the alveolar crest. In adult males, at the first lingual coronal third of the alveolar plate. In adult females, at the buccal apical level. 3) Movement towards cortical bone: In all groups, buccal movements of maxillary central incisors are more critical than of mandibular ones, and lingual movements of mandibular central incisors are more critical than of maxillary ones, especially in adult males. We recommend an accurate diagnosis of incisors position and alveolar bone status, and planning of orthodontic treatment at an earlier age.

Resonance frequency analysis for evaluation of the connecting condition between fixed prostheses and their abutment teeth: An in vitro and finite element analysis study

Statement of problemLoss of retention is a clinical complication for fixed partial dentures (FPDs). However, a method sensitive enough to measure the early retention loss of FPDs is lacking. PurposeThe purpose of this in vitro and finite element analysis (FEA) study was to determine whether resonance frequency analysis (RFA) with a newly developed system can detect lack of FPD retention caused by cement loss. Materials and methodsTwo evaluation methods were used: RFA of an in vitro model of a 3-unit FPD from the second premolar to the second molar and FEA by using a simplified model. The in vitro model was used to evaluate 4 connecting conditions: both crowns cemented, only the premolar crown cemented, only the molar crown cemented, and both crowns uncemented. Tapping stimulation (16 impulsive forces, 4 Hz) was directly applied to the buccal side of the second molar or the second premolar, and an attached 3D accelerometer sensor was used to record the resonance frequency (RF) of the tapped tooth. The amplitude, frequency, Q-value, and total area under the curve (AUC) of the RF values in the buccolingual direction were compared between connecting conditions. The FEA was done by using a simplified model of a 3-unit FPD with similar connecting conditions as the in vitro model study, and the RF amplitude and frequency of each tooth were calculated. Statistical evaluation included 1-way analysis of variance and the Tukey HSD test to compare the differences among each connecting condition under each parameter for measurement sites on the molar and the premolar, respectively (α=.05). ResultsFor both the molar and premolar measurements in both the in vitro and FEA models, when the measurement site was on the uncemented tooth, the amplitude of RF-1 increased, the Q-value of RF-2 decreased, and the area under the curve increased (P<.05). ConclusionsThe same 3 trends found between the measurement sites of the in vitro study and FEA indicated that RFA may be useful for detecting an FPD with loosening caused by cement loss, even partial cement loss.

Effect of Different pH Beverages on the Color Stability of Smart Monochromatic Composite

Omnichroma is a smart monochromatic material and is believed to attain the shade of the surrounding tooth structure in which it is placed. However, the color stability of this material is unknown. Therefore, this study was conducted to evaluate the effect of different pH beverages on the color stability of the Omnichroma composite and its comparison with micro-hybrid composite resin. Sixty extracted human maxillary premolars of different shades, viz. A2, A3, B2 and B3, were selected in equal numbers. A Class V cavity was prepared on the buccal and palatal sides of each tooth. After the cavity preparation, etching of the cavity was performed with 35% phosphoric acid followed by bonding. The prepared cavities were then filled with Omnichroma composite resin on the buccal side and Filtek Z250 composite on the palatal side. The baseline color measurements of all tooth samples were performed by a spectrophotometer. The teeth were then divided into three groups, the Pepsi group, coffee group and milk tea group. Five teeth from each shade, viz. A2, A3, B2 and B3, were immersed in 10-mL of Pepsi, coffee, and milk tea for 14 days. After the completion of the 14 days, the teeth were rinsed and kept in distilled water for 24 h. Finally, a spectrophotometer was used to calculate the color alteration value ΔE. Mean difference in ΔE values of the samples before and after immersion in different beverages was calculated and analysed by SPSS 25. One-way ANOVA test was applied to compare groups. Further stratification was performed using the Post-Hoc Tukeys test. Samples immersed in milk tea showed a statistically significant difference (p &lt; 0.05) in A2, A3, and B2 shades of the OM-milk tea group in comparison with the FT-milk tea group. In summary, the immersion of teeth in beverages with a different pH and colorants showed an apparent alteration in the color of both the smart monochromatic and micro-hybrid composites. Hence, the type of resin composite material should be selected wisely depending on the patient’s drinking and social habits.

Evaluation of maxillary canine root and maxillary bone thickness and density in patients with displaced maxillary canines: A cone-beam tomography study

This study investigated lateral incisor and canine morphology and dimensions, maxillary bone density, and volume in subjects with displaced maxillary canines. Cone-beam computed tomography images for 134 palatally displaced canines (PDCs), 57 buccally displaced canines (BDCs), and 87 nondisplaced canines (NDCs) were analyzed. Canine and lateral incisor dimensions, alveolar bone dimensions, and maxillary bone volume and density were measured. The root length of BDCs was short compared with NDC and PDC groups. The lateral incisor was short in the PDC group compared with NDC and BDC groups. In the BDC group, maxillary bone volume was reduced compared with NDCs and PDCs. Significant differences were detected between BDC and PDC groups in bone density buccal to canines and between BDC and NDC groups in bone density distal to canines. The density of maxillary bone was the highest in the PDC group and the lowest in the BDC group compared with the NDC group. Eight variables were associated with the site of maxillary canine displacement: lateral incisor tip, alveolar bone density, alveolar bone width, bone density buccal to canine, canine width labiopalatally, maxillary bone volume, and canine midsagittal width. In PDCs, the maxillary lateral incisor was short, the canine root had a larger crown/root ratio, and maxillary bone volume was increased compared with NDCs. In BDCs, the canine root was shorter than NDCs and PDCs, maxillary bone volume was reduced compared with NDCs, and bone density at the buccal side was reduced compared with the PDC group.

Biomechanical features of tooth movement from a lingual appliance in comparison with a labial appliance during space closure in sliding mechanics

The objectives of this study were to simulate long-term orthodontic tooth movement in en-masse retraction using the finite element method and investigate the effects of power arms on tooth movements when using a lingual appliance in comparison with a labial appliance. A 3-dimensional finite element model of the maxillary dentition was constructed with 0.018-in brackets and 0.016 × 0.022-in stainless steel archwire. An en-masse retraction was performed by applying retraction force at various lengths of the power arm (4, 6, 8, and 10 mm) to the second molar tube, and long-term tooth movements with the lingual and labial appliances were analyzed using the finite element method. Although lingual crown tipping of the incisor was more marked with the lingual appliance than with the labial appliance in the early phase of space closure, only a slight difference was evident after space closure. Although the power arm was effective for achieving better-controlled tooth movement and reducing vertical and transverse bowing effects, bodily movement of the incisor could not be achieved, and bowing effects could not be eliminated. To provide better torque control of the incisor or prevent a vertical bowing effect, the incorporation of extra torque into brackets of incisors was recommended, and the use of power arms for the lingual appliance. To prevent a transverse bowing effect, incorporation of the antibowing bend or application of retraction force from both buccal and lingual sides or temporary skeletal anchorage devices was recommended.