Evaluation and comparison of stress distribution around periodontally compromised mobile teeth splinted with different materials: Three-dimensional finite element analysis.

BACKGROUND: Progressive attachment loss around the teeth because of periodontal disease can result in increased tooth mobility. This adversely affects patient's comfort, function, and esthetics. Periodontal splinting helps in accomplishing stability by redistributing the functional and parafunctional forces. There are various materials that have been used for periodontal splinting. Fiber-reinforced composite, composite resin, and metal-reinforced composite are often used as splinting materials for periodontally compromised teeth. In our study, a comparison was done among these materials for their ability to distribute the stresses at different bone levels in mobile lower incisors splinted together with canines. MATERIALS AND METHODS: Five patients of age group 25-50 years with Grade 2 and 3 mobile incisors having 40% or more bone loss and firm canines with optimal bone support were selected. From the computed tomography scan of each patient, three models were developed demonstrating splinting of mandibular incisors and canines with metal-reinforced composite, fiber-reinforced composite, and composite resin. So in total, 15 models were developed and each one of them was subjected to vertical and transverse loads of 150 N. Pattern of stress distribution was observed in these models using three-dimensional finite element analysis. RESULTS: After splinting, the stress on the canine increased when bone levels around incisors decreased while stress on incisors reduced. CONCLUSION: Tested splinting materials were successful in stress distribution, and metal-reinforced composite was found to be better than the other splinting materials.

Reattachment of complex fractures; a reality by advances in self-etch bonding systems.

An 18-year-old female patient reported to the Department of Conservative and Endodontics with the chief complaint of fractured tooth with respect to 21 and increased pain and mobility tooth with respect to 22. Intraoral periapical radiograph of 21 revealed coronal loss of tooth structure involving enamel, dentin, and pulp, suggestive of split tooth with respect to 21. Intraoral examination revealed a fracture of coronal structure of 22 and increased mobility in the coronal aspect, suggestive of horizontal crown-root fracture. For management of 21, after endodontic phase, placement of fiberpost, and coronal buildup, intentional reimplantation was done to expose and reattach the vertically fractured root fragment. For management of 22, after endodontic phase, crown lengthening was done, and the fractured fragment was reattached by making it a Natural Richmond's Crown. Radiographs revealed a complete sealing of the fractured fragment and proper positioning of the tooth.

Local injection of RANKL facilitates tooth movement and alveolar bone remodelling.

OBJECTIVES: To investigate the effect of local injection of receptor activator of nuclear factor kappa B ligand (RANKL) on experimental tooth movement and subsequent alveolar bone remodelling in mice. MATERIALS AND METHODS: Sixty mice were randomised to receive daily local RANKL or phosphate-buffered saline injections in the buccal premaxillary bone for 14 of 21 days of incisor movement, followed by a 21-day retention period. Five mice from each group were euthanised on days 0, 3, 7, 14, 21 and 42, and specimens were prepared for haematoxylin and eosin, tartrate-resistant acid phosphatase and immunohistochemical staining. Five mice from each group were subjected to serial microcomputed tomography until day 42 for tooth movement and bone volume quantification. RESULTS: The experimental group showed significantly greater tooth movement and bone volume reduction on days 14 and 21; an increased osteoclast number on days 3, 7, 14 and 21; and no difference on day 42. Higher RANKL expression was observed on days 7 and 14, with remarkable alkaline phosphatase activity. No significant systemic changes were observed. CONCLUSION: Local RANKL injection leads to increased osteoclastic activity and facilitates tooth movement, followed by subsequent alveolar bone formation; this implies a reversible transitional acceleration of bone resorption.

Microanatomical changes and biomolecular expression at the PDL-entheses during experimental tooth movement.

The novel aspect of this study was to contextualize the co-localization of biomolecular expression in widened and narrowed periodontal ligament (PDL)-space within a mechanically activated periodontal complex. The PDL is unique as it is the only ligament with both innervation and vascularization. Maxillary molars in 6-week-old male C57BL/6 mice (N = 5) were experimentally translated for 2 weeks using an elastic spacer. Contralateral teeth were used as controls. Mechanical testing of the periodontal complex of a mouse in situ and imaging using X-ray micro-computed tomography (micro-XCT) illustrated deformations within blood vessels (BV) of the PDL. PDL-bone and PDL-cementum entheses at the widened and narrowed PDL-spaces following experimental tooth movement (ETM) illustrated osterix (OSX), bone sialoprotein (BSP), cluster of differentiation 146 (CD146), and protein gene product 9.5 (PGP9.5), indicating active remodeling at these sites. PGP9.5 positive nerve bundles (NBs) were co-localized with multinucleated cells (MCs), Howship's resorption lacunae, and CD146 positive BVs. Association between nerves and MC was complemented by visualizing the proximity of osmium tetroxide stained NBs with the ultrastructure of MCs by performing scanning transmission electron microscopy. Spatial association of NB with BV, and NB with MC, provided insights into the plausible co-activation of NBs to initiate osteoclastic activity. Resorption of mineral occurred as an attempt to restore PDL-space of the load-bearing complex, specifically at the PDL-entheses. Mapping of anatomy-specific structural elements and their association with regenerative molecules by correlating light and electron micrographs provided insights into the use of these extracellular matrix molecules as plausible targets for pharmacological interventions related to tooth movement. Within the realm of tissue regeneration, modulation of load can reverse naturally occurring mineral formation to experimentally induced resorption, and naturally occurring mineral resorption to experimentally induced formation at the enthesial sites to permit tooth translation.

Dynamic Evaluation of Orthodontically-Induced Tooth Movement, Root Resorption, and Alveolar Bone Remodeling in Rats by in Vivo Micro-Computed Tomography.

BACKGROUND The aim of this study was to dynamically evaluate tooth movement, root resorption, and remodeling of alveolar bone using different forces to cause tooth movement in rats. MATERIAL AND METHODS 12-week-old male Sprague-Dawley rats were selected. Nickel-titanium (Ni-Ti) coil springs (20 g, 50 g, and 100 g forces) were placed for mesial movement of the left first maxillary molar teeth. Tooth movement, root resorption, and microarchitectural parameters of the trabecular bone were evaluated by in vivo micro-CT. Histological examination was used to observe the root resorption, alveolar bone remodeling, and changes in osteoclasts from day 0 to day 14. RESULTS The tooth movement distance increased significantly over the initial 3 days in the 3 groups. The 20 g force group showed more tooth movement than in the 50 and 100 g force groups after 14 days (P<0.05). From days 7 to 10, root resorption lacunae appeared in the 3 groups and then stabilized, and the 100 g force group produced more lacunar resorption than in the anther 2 groups (P<0.05). Compared to day 0, the trabecular thickness and bone volume fraction on the pressure side gradually decreased from day 7 to day 14. The structure model index increased significantly from day 3 to day 14. Histological examination showed remarkable root resorption craters and osteoclasts positive for tartrate-resistant acid phosphatase in the root resorption lacunae in the 50 g and 100 g groups from day 7 to day 14. CONCLUSIONS A 100 g heavy force can be used to establish a root resorption model in rats.

Effect of incisal loading during orthodontic treatment in adults: A randomized control trial.

OBJECTIVE: To measure the changes in tooth mobility, alveolar bone, and receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin (OPG) in the gingival crevicular fluid (GCF) during orthodontic treatment to regain incisal function in the presence and absence of biting exercises. MATERIALS AND METHODS: Thirty-six females (42.3 ± 6.5 years old) with periodontally compromised upper incisors received orthodontic treatment to obtain ideal incisor relationships. Eighteen subjects in the experimental biting exercise group were instructed to bite a soft plastic roll for 5 min/d; the 18 control subjects were not given plastic rolls. Alveolar bone thickness, height, and density around the upper incisors were assessed at three root levels using cone-beam computed tomography. GCF was collected at the labial and palatal sites of the upper incisors at pretreatment (T0), end of treatment (T1), 1 month after T1 (T2), and 7 months after T1 (T3). RANKL/OPG was determined using enzyme-linked immunosorbent assays. RESULTS: Labial and palatal bone thickness significantly increased (>twofold) from T1 to T3 in the experimental group at all three root levels (all P < .05). Bone thickness correlated negatively with RANKL/OPG ratio between T1 and T2 ( P < .05). Tooth mobility, bone height, and density were not significantly different between T1 and T3. CONCLUSIONS: Biting exercises significantly increased bone thickness but did not affect tooth mobility, bone height, or density. The RANKL/OPG ratio decreased 1 month after treatment (T2) and correlated with increased bone thickness. ( ClinicalTrials.in.th TCTR20170625001).

[A study on effects of immediate bone grafting at mandibular first molar fresh extraction socket on maintaining alveolar bone height after space closure].

Objective: To investigate the effect of immediate bone grafting at mandibular first molar extraction socket on maintaining alveolar bone height after space closure. Methods: Thirty adult orthodontic patients who need to extract mandibular first molar, totally 38 target teeth, were included. The samples were divided into two groups randomly: graft group and non-graft group. All extraction space was closed orthodontically. Dental models of all patients were taken before extraction (T0), before space closure(T1) and after space closure (T2). The distance, time of the space closure and the velocity of tooth movement were recorded. Probing depth (PD) and clinical attachment level (CAL) at six sites (mesial buccal, buccal, mesial lingual, lingual, distal buccal and distal lingual) on adjacent teeth were measured before extraction (T0) and after space closure (T2). Cone-beam CT (CBCT) was taken at T0 and T2 to compare the changes of alveolar bone height at six sites on adjacent teeth using Invivo Dental 5.0 software. Results: The extraction space in both graft group and non-graft group was closed successfully. However, the space in graft group was closed more slowly than in non-graft group. In graft group, PD and CAL at the six sites on both the second molar and the second premolar did not change significantly after space closure, and CBCT showed that the alveolar bone height of the second premolar had no significant difference after treatment. In non-graft group, alveolar bone height decreased in both adjacent teeth and periodontal attachment loss was found after space closure. On average, alveolar bone height and periodontal attachment of the second premolar decreased (0.75±0.16) mm and (0.64±0.15) mm, respectively. Meanwhile, alveolar bone height and periodontal attachment of the second molar decreased (0.79±0.23) mm and (0.80±0.24) mm, respectively. Conclusions: Bone graft immediately after mandibular first molar extraction could delay alveolar bone resorption and preserve the periodontal attachment of the adjacent teeth during space closure. However, the procedure could slow down tooth movement.

An alternative impression technique for mobile teeth.

The impression technique described combines elastomeric impression materials and irreversible hydrocolloid to make an accurate preliminary impression of extremely mobile and misaligned teeth. Upon setting, the materials are removed from the mouth in 3 different directions and reassembled extraorally. This technique provides an alternative, easy, accurate, and safe way to make a preliminary impression of mobile, periodontally involved teeth.

Effect of placing intentionally high restorations: Randomized clinical trial.

OBJECTIVE: The aim of this study was to examine the behavior of posterior teeth restored with single-tooth restorations with intentionally high occlusal contacts. METHODS: Consent was obtained from 17 patients who were seen a total of 5 times over 3.5 years. The restorations placed were all full occlusal coverage gold restorations. Tooth mobility was recorded using the Periotest device and tooth movement was determined from impressions and 3D imaging. Patients were randomly assigned into two groups, the control group which received restorations with no intentional increase of the occlusal vertical dimension; or the treatment group where they received intentionally high restorations in 0.5mm supraocclusion. RESULTS: Statistical analysis showed no significant difference in mobility between visits for both the control and the treatment groups while a significant dependency and difference in tooth movement was observed between the subjects of the two groups. Most patients from the treatment group reported discomfort but no pain for the first 7-10 days after the restoration was fitted, which subsided over a period of couple of weeks. At review, 3 years later, no mobility or additional movement was observed. CONCLUSIONS: Cementation of an intentionally high single-tooth restoration causes no increase in tooth mobility while occlusal adaptation re-establishes and restores the occlusal plane.

Idiopathic Radiographic Apical Root Resorption in Wind Instrument Players.

Root resorption of the permanent teeth involves an elaborate interaction among inflammatory cells resulting in loss of dental hard tissues. This report describes three clinical cases where idiopathic root resorption occurred in wind instrument playing patients. These patients produce adequate non-orthodontic forces, while playing their instruments, to expose their teeth to root resorbing force. Careful clinical monitoring of patients' teeth should be undertaken, as the additive effects of orthodontic treatment and musical habits are unknown. CPD/Clinical Relevance: This paper advises that questioning about wind instrument playing during case history-taking would be beneficial to clinicians. Furthermore, careful clinical monitoring of these patients' teeth during orthodontic treatment should be undertaken.

Low-intensity pulsed ultrasound accelerates tooth movement via activation of the BMP-2 signaling pathway.

The present study was designed to determine the underlying mechanism of low-intensity pulsed ultrasound (LIPUS) induced alveolar bone remodeling and the role of BMP-2 expression in a rat orthodontic tooth movement model. Orthodontic appliances were placed between the homonymy upper first molars and the upper central incisors in rats under general anesthesia, followed by daily 20-min LIPUS or sham LIPUS treatment beginning at day 0. Tooth movement distances and molecular changes were evaluated at each observation point. In vitro and in vivo studies were conducted to detect HGF (Hepatocyte growth factor)/Runx2/BMP-2 signaling pathways and receptor activator of NFκB ligand (RANKL) expression by quantitative real time PCR (qRT-PCR), Western blot and immunohistochemistry. At day 3, LIPUS had no effect on the rat orthodontic tooth movement distance and BMP-2-induced alveolar bone remodeling. However, beginning at day 5 and for the following time points, LIPUS significantly increased orthodontic tooth movement distance and BMP-2 signaling pathway and RANKL expression compared with the control group. The qRT-PCR and Western blot data in vitro and in vivo to study BMP-2 expression were consistent with the immunohistochemistry observations. The present study demonstrates that LIPUS promotes alveolar bone remodeling by stimulating the HGF/Runx2/BMP-2 signaling pathway and RANKL expression in a rat orthodontic tooth movement model, and LIPUS increased BMP-2 expression via Runx2 regulation.

The anatomical evaluation of the dental arches using cone beam computed tomography--an investigation of the availability of bone for placement of mini-screws.

OBJECTIVE: To assess the amount of maxillary and mandibular inter-radicular bone mass and determine the most reliable mini-screw placement sites. MATERIALS AND METHODS: Retrospective Cone Beam Computed Tomography (CBCT) images of 40 Angle Class I subjects (20 females, 20 males, aged 16 to 32) were obtained. Measurements on the buccal (BI), medial (MI) and lingual (LI) sides of the inter-radicular spaces were taken at 0, 1, 2, 3, 4, 5 mm from the cemento-enamel junction (CEJ) in an apical direction. RESULTS: The male and female BI scores ranged from 2.99±0.73 mm to 6.18±1.03 mm and 2.69±0.84 mm to 6.21±1.22 mm respectively. The male and female MI scores ranged from 1.36±0.38 mm to 4.50±0.99 and 1.53±0.66 to 4.77±1.99 mm respectively. LI scores ranged from 2.37±0.70 to 6.47±1.0 mm and 2.45±0.56 mm and 6.66±1.33 mm respectively. In both maxillary and mandibular arch, the inter-radicular space increased in the apical direction except for the buccal and medial inter-radicular spaces between the maxillary first and second molars. CONCLUSION: The medial inter-radicular spaces are the decisive parameter for mini-screw placement. In the maxillary arch, regions between central and lateral incisors, lateral incisor and canine, first and second molars are not viable for mini-screw insertion. The residual inter-radicular regions are proper for implantation at 3 mm above the CEJ. In the mandible, the regions between incisors and canines are too narrow for mini-screw insertion and the reliable sites for mini-screws are regions between premolars, molars or first molar and second premolar at 2 mm below the CEJ.

Oral mucosal morphea: a new variant.

Morphea is a cutaneous disorder characterized by an excessive collagen deposition. While in almost all cases the sclerosing process exclusively affects the skin, there are anecdotal cases in which associated mucosal involvement has been described. We here report the case of a woman developing a whitish indurated plaque over the left upper vestibular mucosa and hard palate leading to dental mobility and exposure of the roots of several teeth. Cone beam computed tomography of the left maxilla showed bone resorption involving the upper cuspid to the second molar region with widened periodontal ligament spaces, while light microscopy studies demonstrated epithelial atrophy and fibrosis of the dermis extending into the submucosa with hyalinization of subepithelial collagen. Our observation expands the spectrum of clinical presentations of morphea and provides the first example of isolated oral morphea. Its recognition is important to avoid significant local complications.

Radiographic findings in bisphosphonate-treated patients with stage 0 disease in the absence of bone exposure.

PURPOSE: Radiographic features in patients with bisphosphonate-related osteonecrosis of the jaw (BRONJ) are well described, but less is known in bisphosphonate-exposed individuals with stage 0 disease (clinical symptoms without exposed necrotic bone) considered at risk for BRONJ. We sought to characterize radiographic findings in a subgroup of patients with concerning clinical symptoms and bisphosphonate exposure to identify imaging features that may presage development of BRONJ. MATERIALS AND METHODS: A dental symptom survey was returned by 8,572 Kaiser Permanente Health Plan members receiving chronic oral bisphosphonate therapy, and 1,005 patients reporting pertinent dental symptoms or complications after dental procedures were examined. Those without BRONJ but with concerning symptoms were referred for clinical evaluation, including imaging. Among the subset who received maxillofacial imaging, we identified those with stage 0 disease and abnormal radiographic features. RESULTS: There were a total of 30 patients without exposed bone but with concerning symptoms who received maxillofacial imaging (panoramic radiography or computed tomography) in the context of clinical care. Among these 30 patients, 10 had stage 0 disease with similar radiographic features of regional or diffuse osteosclerosis in clinically symptomatic areas, most with extension beyond the involved site. Other findings in these 10 patients included density confluence of cortical and cancellous bone, prominence of the inferior alveolar nerve canal, markedly thickened and sclerotic lamina dura, uniform periradicular radiolucencies, cortical disruption, lack of bone fill after extraction, and a persisting alveolar socket. None had exposed bone develop during 1-year follow-up. The remaining 20 patients had normal or localized radiographic findings consistent with odontogenic pathology. CONCLUSION: In 10 of 30 symptomatic patients referred for clinical evaluation and imaging, a consistent finding was conspicuous osteosclerosis in clinically symptomatic areas characteristic of stage 0 disease. These data support the need to better understand radiographic features associated with bisphosphonate exposure and to determine whether osteosclerosis is a specific finding indicative of the risk for progression to BRONJ.

Prognosis for abutment teeth of removable dentures: a retrospective study.

PURPOSE: This retrospective study evaluates the clinical success of conical crown-retained removable dentures. MATERIALS AND METHODS: Ninety-seven patients were treated with 97 dentures at the University of Frankfurt, Department of Prosthodontics, between 1993 and 2000. The average observation period was 4.9 +/- 2.8 years. The dentures were supported by 445 natural abutment teeth. To evaluate the long-term success of the restorations, the variables abutment loss, tooth mobility, mean probing depths, and radiological bone loss were used. Data were obtained by one clinical examiner at baseline, by systematic evaluation of patient records, and at clinical re-examinations. Survival-time methods were used to analyze time-to-event data. Specifically, the Cox model with frailty term was applied to account for correlations between intra-patient survival data. Thirty abutment teeth had to be extracted during the observation period. RESULTS: Statistical analysis showed no significant effects of the variables tooth mobility (p= 0.42), mean probing depths (p= 0.23), and radiological bone loss (p= 0.59) on the time to tooth extraction. For the non-extracted abutment teeth significant changes during time for the variables tooth mobility (p < 0.0001) and radiological bone loss (p= 0.0240) were observed. CONCLUSION: Removable partial dentures retained by conical crowns have a favorable clinical prognosis.

Measuring mobility of 2 dental implant fixtures of different configurations: an in vitro study.

OBJECTIVES: To our knowledge, it has not as yet been determined if mini-dental implants can be used as a long-term treatment method compared to endosseous standard root-form dental implant fixtures. This in vitro study investigates the stability of 2 different implants, 1 mini-dental implant and 1 endosseous standard root form dental implant, under lateral forces. METHODS: There were 2 different screw-type dental implants with the O-ring/ball attachment prosthetic heads used. A mini-dental implant (Sendax MDI MAX; IMTEC, Corp., Ardmore, OK) 13 mm in length and 2.2 mm in diameter, and root form implant (Brånemark; Nobel Biocare AB, Goteborg, Sweden) 13 mm in length and 4 mm in diameter. These implants were then embedded into a matrix mixture of pumice, two-fifths BaSO4 powder and one-fifth plaster. Parallel periapical radiographs were taken pretest and after lateral forces were applied. The implants were vibrated using electric toothbrushes. They were attached to O-rings on the implants. Periapical radiographs were secured periodically every 5 minutes. The first discrepancy was observed at the 35th minute. Mobility and discrepancy values were recorded at the instances of 35th, 60th, 90th, and 120th minutes. Stability was measured and recorded using a manual stress and tension gauge. Radiographic discrepancy values were measured using a stereomicroscope. RESULTS: The Brånemark implant showed less mobility and discrepancy values than the mini-dental implant. The discrepancies were observed mostly at the cervical region of the 2 implants. CONCLUSIONS: According to the experimental results of this study, the Brånemark implant was more stable than the mini-dental implant at the end of 2 minutes.

Oral rehabilitation of a patient with diffuse lymphangiomatosis affecting the maxilla: a case report.

A case is presented in which diffuse lymphangiomatosis resulted in the complete loss of the maxillary dentoalveolar complex and underlying basal bone. The complex investigation and treatment of this patient over a 10-year period is presented, and the importance of a multidisciplinary team approach in providing a functional and esthetic rehabilitation is highlighted. The use of a vascularized bone graft based on the deep circumflex iliac artery and subsequent restoration with an implant-supported prosthesis is described.

Orthodontic approach for patients with severe periodontal disease.

Although comprehensive orthodontic treatment cannot preclude the possibility of periodontal disease developing later, it can be a useful part of the overall treatment plan for a patient who already has periodontal involvement. A careful clinical examination must determine the patient's dental health status, including any existing destruction or deficiencies of the teeth and their support, as well as the patient's ability to achieve and maintain good overall oral hygiene. Two major criteria should be considered in the treatment of these patients: (1) the patient should be seen frequently for periodontal maintenance and (2) minimal orthodontic forces should be applied. Segmented archwires could be used for the treatment mechanics. After treatment, splinting of the teeth is necessary both short- and long-term. With this orthodontic approach, both dental esthetics and function improve and can be maintained. A male patient, 50 years of age, with severe periodontal involvement was referred to the authors' clinic, from the periodontal department, for treatment. The mandibular incisors were intruded by using segmental archwires. At the end of treatment, permanent retention was required due to the severe bone loss.

Evaluation of transversal slice imaging in the diagnosis of tooth displacement with special consideration of the upper canines.

AIM: The exact localization and analysis of displaced, retained or impacted teeth can rarely be achieved by common radiologic methods providing eccentric or occlusal images. The aim of this study was to evaluate transversal slice imaging (TSI) as a diagnostic alternative, keeping radiation exposure under consideration. MATERIAL AND METHODS: In a pilot study, we simulated seven different canine positions in a phantom head. Each tooth position was visualized by transversal slice imaging and compared by several observers independently and blinded to computer tomography (CT) serving as the gold standard. The clinical study included the retrospective analysis of TSI samples from 27 patients (mean age 13.7 yrs.) according to these criteria: 1. location of the canine crown and root, 2. recognition of the crown, 3. stage of root development, 4. root dilaceration, 5. periodontal ligament space, 6. ankylosis, 7. relationship to neighboring teeth, and 8. resorptions of neighboring teeth. The evaluations of canine position were compared to the results gained intraoperatively. RESULTS: In the transversal slice images taken from a phantom head, the observers' estimations of the canine position were identical in five cases (71.4%). At least four observers using TSI described identical tooth positions in 89% of patients. In 2.5%, no statement concerning tooth position was feasible. Crown recognition was possible in 75% of cases. Ankylosis, periodontal ligament space, root development, dilacerations and resorptions were not assessable in the majority of the cases. CONCLUSION: Transversal slice imaging can be recommended as a second plane projection in diagnosing tooth displacement, especially concerning oro-vestibular localization (effective radiation dose 0.003-0.012 mSv). However, as far as periodontal ligament space, resorptions and root morphology are concerned, this method has its limits.