Cleansing efficacy of an oral irrigator with microburst technology in orthodontic patients-a randomized-controlled crossover study.

OBJECTIVES: Orthodontic patients struggle with interdental cleaning calling for simpler mechanical devices to reduce the high plaque levels. The present study aimed to compare the cleansing efficacy of an oral irrigator with that of dental flossing in patients with fixed braces after 4 weeks of home-use. MATERIALS AND METHODS: The study design is a randomized and single-blinded cross-over study. After 28 days using the products at home, hygiene indices (Rustogi Modified Navy Plaque Index (RMNPI); gingival bleeding index (GBI)) were compared between test (oral irrigator) and control product (dental floss). RESULTS: Seventeen adult individuals finalized the study. After 28 days of cleaning with the oral irrigator, RMNPI was 54.96% (46.91-66.05) compared to 52.98% (42.75-65.60) with dental floss (p = 0.029). Subgroup analysis revealed that the higher cleansing efficacy of the dental floss is attributable to buccal and marginal areas. GBI after the test phase with the oral irrigator was 12.96% (7.14-24.31) and statistically significantly higher compared to 8.33% (5.84-15.33) with dental floss (p = 0.030) which could be seen in all subgroups. CONCLUSIONS: Oral irrigators do not remove plaque and reduce gingival bleeding as efficiently as dental floss in easily accessible regions. However, in posterior regions, where the patients struggled with the application of dental floss, the oral irrigator showed similar results. CLINICAL RELEVANCE: Oral irrigators should only be recommended to orthodontic patients who cannot use interdental brushes and are not compliant with dental flossing.

Comparison between stone and digital cast measurements in mixed dentition : Validity, reliability, reproducibility, and objectivity.

PURPOSE: To assess the validity, reliability, reproducibility, and objectivity of measurements on stone casts of patients with mixed dentitions compared to measurements on three-dimensional (3D) digital models derived from surface scans of the stone casts. METHODS: Pairs of stone casts of 30 young patients in their mixed dentition stage were included and processed into 3D digital models using an intraoral scanner (iTero Element 2; Align Technology, San Jose, CA, USA). Then an experienced and an inexperienced examiner independently performed measurements of five defined parameters, each in triplicate, both on the digital models with analysis software (OnyxCeph3™; Image Instruments, Chemnitz, Germany) and on the original casts with a vernier calliper. Paired t-tests were used for validity and interexaminer objectivity, Pearson correlation coefficients for intermethod reliability, and intraclass correlation coefficients (ICCs) for reproducibility testing. RESULTS: Significant (p < 0.05) intermethod differences were identified for four parameters, but only the differences for overbite and intermolar distance exceeded the threshold of clinical relevance (≥ 0.5 mm). Intermethod reliability was high and method error invariably lower for the digital measurements and for the experienced examiner. Both examiners achieved ICCs > 0.907 with both methods. Interexaminer variation involved significant differences for all parameters but one (intermolar distance) on the stone casts and for three parameters on the digital models. CONCLUSION: Measurements performed on digital models of mixed dentitions can yield clinically acceptable outcomes with OnyxCeph3™ software. Both the digital and the analogue measurements were highly reproducible and reliable. Objectivity of the measurements could not be confirmed, as operator experience did make a difference.

Nrf2 in the Field of Dentistry with Special Attention to NLRP3.

The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health.

Maxillary expansion or contraction and occlusal contact adjustment: effectiveness of current aligner treatment.

OBJECTIVES: To evaluate the precision of aligner (Invisalign®) treatment with the current material (SmartTrack®) in achieving expansion or contraction of the maxilla and occlusal contacts as simulated in the proprietary planning software (ClinCheck®, CC). MATERIALS AND METHODS: Thirty patients thus treated were retrospectively evaluated. Four maxillary models were analyzed per patient: a pretreatment model, a scan-based CC model, a posttreatment clinical model, and a CC model reflecting the treatment outcome as initially simulated. Thirteen transverse parameters were measured on each model separately by two investigators. Occlusal contacts were also analyzed. RESULTS: The measuring method was validated by both investigators arriving at similar results for the effectiveness by which the simulated treatment goals had been clinically achieved. Significant differences (p < 0.05; Wilcoxon signed-rank test) were observed for transfer precision from the casts to the planning software and between the simulated and clinical outcomes. Intense occlusal contacts in the simulations materialized less common (≈ 2%) than ideal contacts (≈ 60%) in the clinical outcomes. CONCLUSIONS: The effectiveness of achieving the simulated transverse goals was 45% and was generally not found to be better with SmartTrack® than with the previously used Ex30® material. Out of 100 simulated occlusal contacts, 40 will never materialize, and achieving around 60 will adequately ensure a clinically favorable contact pattern. CLINICAL RELEVANCE: With the caveat that any overcorrection will to some extent reduce the precision, it seems perfectly possible to make deliberate use of overcorrection in current aligner therapies for transverse maxillary expansion or contraction.

Impression material accuracy for palatal orthodontic miniscrews.

PURPOSE: This study investigates the accuracy of abutment transfer with current impression materials and provides a concise overview, including other relevant factors, in order to enable clinicians to make an informed decision about the optimal impression for this treatment procedure. METHODS: In all, 96 impressions of a cadaver head with two orthodontic miniscrews in place were taken with four common impression materials by two observers and using two methods of application. After pouring with a standard type IV stone and abutment transfer, all models and the upper jaw (which had been separated from the head) were scanned in a standard model scanner (Zirkonzahn® [Zirkohnzahn GmbH, Gais, Italy] S600 ARTI) and evaluated using a computer-aided design (CAD) program (GOM-Inspect [Gesellschaft für optische Messtechnik m.b.H., Braunschweig, Germany]). The deviations were measured at six points per screw and statistically evaluated with SPSS® (IBM, Chicago, IL, USA). RESULTS: Optimal values were obtained with biphasic polyvinylsiloxane, while monophasic polyvinylsiloxane, alginate and polyether also resulted in acceptable accuracy. Observer experience showed no effect and the method of application had only a minor effect on accuracy. CONCLUSIONS: Within the limitations of this study, it seems that all impression materials are suitable for miniscrew abutment transfer, provided that methods of intraoral adaptation of the orthodontic appliance can be employed. If higher accuracy is needed or for clinicians with less experienced, a biphasic polyvinylsiloxane impression with the putty-wash technique should be used as this combination reduces setting time. The most cost-effective version, alginate, can be used if the consequences of greater deviations can be handled. Caution is advised with polyether if undercuts are present.

Dental Management and Prosthetic Rehabilitation of Patients Suffering from Hypohidrotic Ectodermal Dysplasia: A Report of Two Case Histories.

The prosthetic restoration and dental long-term care of two oligodont male cousins suffering from X-linked hypohidrotic ectodermal dysplasia is described in two case histories. The first patient was three times supplied with removable dentures at an age from 5 to 12 years, and the second patient was restored twice by tooth- and implant-supported dentures within an observation period of 10 years. In both patients, implants were placed in the growing jaw (both arches) in order to enhance denture retention by single attachments and/or a palatinal bar. In one patient, loss of one maxillary implant occurred 3 years after implant exposure and 2 years after the provision of the implant-supported denture. In the second patient, after completion of growth and preceding bone augmentation, further implants facilitated an improved removable maxillary restoration. In both patients, an orthodontic alignment and reshaping of the conical anterior teeth by means of resin or full-ceramic crowns was applied to improve the esthetic appearance. Patients with HED require a consistent lifelong attendance comprised of oral hygiene, denture maintenance, and refitting. In oligo-/anodont children, the placement of implants in selected regions may be useful for the enhancement of denture retention. However, due to poor bone quality and volume, implant failure may occur.

Transfer accuracy of two indirect bonding techniques-an in vitro study with 3D scanned models.

Background and objectives: Indirect bonding (IDB) proved to be an effective method for appropriate bracket positioning in patients. Different methods and materials are available for fabricating transfer trays. This in vitro study was designed to measure and compare the transfer accuracy of two common IDB methods. Materials and methods: Sixty stone models were fabricated and separated in two groups of 30 models each (15 working models, 15 patient models). After placing brackets on the working models, 30 IDB trays were made: 15 silicone (method I) and 15 double-vacuum forms (method II). With these trays, the brackets were transferred to the patient models. The bracket positions were scanned before and after the IDB procedure with an intraoral scanner. The linear and angular discrepancies were then determined digitally by measuring six different dimensions: occluso-cervical, mesio-distal, bucco-lingual, tip, rotation, and torque. Results: The silicone trays showed fewer transfer discrepancies, on average, in all measured dimensions. There were significant differences between the methods in the occluso-cervical (P < 0.001), mesio-distal (P = 0.001), and torque (P = 0.044) dimensions. With both methods, 100 per cent of the horizontal and transversal measurements of both methods were within the clinically acceptable range of 0.25 mm. With method I, 98.5 per cent of the vertical and 95.9 per cent of the angular measurements were within the range of 0.25 mm and 1°, respectively. With method II, 94 per cent of the vertical and 84.8 per cent of the angular measurements were within the clinically acceptable range. Conclusions: Although both transfer methods showed a high precision, silicone trays scored better in terms of accuracy than double-vacuum forms.

Dental age is more appropriate than chronological age for evaluating the mandibular movement range in children.

PURPOSE: The measurement of excursive jaw movements is an important instrument for evaluating the functional condition of the temporomandibular system. Dento-maxillofacial development differs widely within different age, weight or height clusters. Tooth eruption is part of the development of the temporomandibular system. Therefore, the dental developmental stage might reflect temporomandibular development more appropriately. The aim of this study was to investigate whether the dental age is a more suitable parameter for evaluating the mandibular movement range of children in the mixed dentition stage than chronological age. MATERIALS AND METHODS: In a prospective study, the mandibular movement range and relevant temporomandibular findings of 146 children aged 8-10 yr were assessed clinically. Alginate impressions were taken and dental casts were generated. Dental age was assessed from the casts. RESULTS: The mean mouth opening capacity was 46.2 mm (SD = 5.2); the mean laterotrusion to the left was 10.1 mm (SD = 1.9) and to the right 10.0 mm (SD = 1.8). For protrusion, the mean value was 9.1 mm (SD = 2.0). There was a statistically highly significant correlation between dental age and maximal active mouth opening extent. Statistically significant correlations between chronological age and active jaw movement capacity could not be shown. CONCLUSIONS: In children in the mixed dentition stage, dental age seems to reflect the developmental stage of the temporomandibular system more adequately than chronological age. Therefore, dental age-related normative values could be more appropriate for evaluating the temporomandibular system in children. CLINICAL TRIAL REGISTRATION NUMBER: 20100302-161.

Orthodontic Treatment Need of Austrian Schoolchildren in the Mixed Dentition Stage.

Malocclusal traits can impair dental health and aesthetical appearance. The index of orthodontic treatment need (IOTN) identifies the patients who benefit the most from orthodontic treatment. The aim of this study was to assess the malocclusion frequencies and the orthodontic treatment need among Austrian children in the mixed dentition stage, since there is no pre-existing data from Austria. In the present study, 157 children aged between 8 and 10 years were examined. Following an anamnesis questionnaire, which included a question about the parents' perceived treatment need, the children were examined clinically and dental impressions were taken. The sagittal molar relationship, overjet, overbite and the presence of cross- or scissor bite were registered. The treatment need was assessed using the dental health component (DHC) of the index of orthodontic treatment need (IOTN). 64.3% (95% CI [56.8, 71.8]) of the children showed Angle class I molar relation, 33.1% (95% CI [25.8, 40.5]) class II and 2.5% (95% CI [0.1, 5.0]) Angle class III relation. Crossbite was found in 36.3% (95% CI [28.8, 43.8]) of the participants. A treatment need for medical reasons (IOTN 4 or 5) was found in 30.6% (95% CI [23.4, 37.8]). There was no statistically significant relationship between objective treatment need and the parents' perception. The malocclusion frequencies and the treatment need assessed in the present study appeared to be comparable to those assessed in other countries. The data supports the opinion that orthodontic screening is important and necessary at this stage of dental development, also due to the discordance between objective and perceived treatment need.

Behavior of osteoblasts on TI surface with two different coating designed for orthodontic devices.

In the present study we coated Ti surfaces with polytetrafluorethylene (PTFE) and titanium nitride (TiN) and investigated in vitro the behavior of osteoblasts on these surfaces. MG-63 osteoblasts were cultured on titanium discs with different surface treatment: uncoated Ti6Al4V, TiN-coated, PTFE-coated. Cell viability/proliferation was detected by MTT assay. Gene-expression levels of alkaline phosphatase (ALP), osteocalcin (OC), type I collagen, receptor activator of nuclear factor-kappa-B ligand (RANKL), and osteoprotegerin (OPG) were determined by qPCR. Cell behavior on different surfaces was observed by time-lapse microscopy. Cells grown on PTFE-coated Ti surface exhibited delayed surface attachment and decreased proliferation after 48 h. However, after 168 h of culture cells grown on PTFE-coated surface exhibited higher viability/proliferation, higher expression levels of ALP and OC, and higher OPG/RANKL ratio compared to uncoated surface. No effect of TiN-coating on any investigated parameter was found. Our results shows that PTFE coating exhibits no toxic effect on MG-63 cells and slightly stimulates expression of several genes associated with osteogenesis. We propose that PTFE coating could be considered as a possible choice for a surface treatment of temporary skeletal anchorage devices in orthodontics.

The association of chronic apical periodontitis and endodontic therapy with atherosclerosis.

OBJECTIVES: Chronic apical periodontitis (CAP) appears to be a risk factor for coronary heart disease. The aims of the study were to estimate the significance of AP for the atherosclerotic burden and to examine the potential effect of endodontic treatment. MATERIALS AND METHODS: The whole-body computed tomography (CT) examinations of 531 patients with a mean age of 50 ± 15.7 years were evaluated retrospectively. The atherosclerotic burden of the abdominal aorta was quantified using a calcium scoring method. The parameters of periodontitis were measured using the CT scan. RESULTS: The patients had a total of 11,191 teeth. The volume of the aortic atherosclerotic burden for patients with at least one CAP lesion was 0.32 ± 0.92 ml, higher than for patients with no CAP (0.17 ± 0.51 ml; p < 0.05). The atherosclerotic burden increased with age and number of CAP lesions without root canal treatment, but not with number of CAP lesions with endodontic treatments (p < 0.05 each). In logistic regression models, age (Wald 90.8), CAP without endodontic treatment (Wald 39.9), male gender (Wald 9.8), and caries per tooth (Wald 9.0) correlated positively and the number of fillings (Wald 11) correlated negatively with the atherosclerotic burden (p < 0.05 each). Apical radiolucencies in teeth with endodontic treatment were irrelevant with respect to atherosclerosis. CONCLUSIONS: CAP correlated positively with the aortic atherosclerotic burden. In regression models, CAP without endodontic treatment was found to be an important factor, not however apical radiolucencies in teeth with endodontic treatment. CLINICAL RELEVANCE: Further research is needed to clarify the possible clinical significance of these associations.

Inter- and intraobserver variability in resonance frequency analysis of palatal implants--a technical note.

PURPOSE: To assess inter- and intraobserver variability in wireless resonance frequency analysis (RFA) stability measurements of palatal implants and to evaluate the influence of age, sex, time after implant insertion, and measurement direction on variability. MATERIALS AND METHODS: Three observers conducted wireless RFA stability measurements of palatal implants from 16 patients. Measurements were taken in anteroposterior and laterolateral directions and were repeated after 1 hour. RESULTS: Data showed a small interobserver variation (1.93) with intraobserver variation (1.77) as its largest component. Time after implantation showed a strong influence (P = .027) on the interobserver variation. CONCLUSIONS: The tested wireless RFA device can be considered a reliable instrument for measuring the stability of palatal implants. Multiple readings and observers could further improve measurement reliability.

The occurrence of dental caries is associated with atherosclerosis.

OBJECTIVE: Previous studies have suggested that marginal periodontitis is a risk factor for developing atherosclerosis. The objective of this study was to determine whether caries may also be associated with atherosclerosis. METHODS: The computed tomography data sets of 292 consecutive patients, 137 women and 155 men with a mean age of 54.1±17.3 years, were analyzed. Caries were quantified based on the number of decayed surfaces of all the teeth, and periodontitis was quantified on the basis of the horizontal bone loss in the jaw. The presence of chronic apical periodontitis (CAP) was assessed, and the aortic atherosclerotic burden was quantified using a calcium scoring method. RESULTS: The patients with <1 caries surfaces/tooth had a lower atherosclerotic burden (0.13±0.61 mL) than patients with ≥1 caries surfaces/tooth. The atherosclerotic burden was greater in patients with a higher number of lesions with pulpal involvement and more teeth with chronic apical periodontitis. In the logistical regression models, age (Wald 49.3), number of caries per tooth (Wald 26.4), periodontitis (Wald 8.6), and male gender (Wald 11) were found to be independent risk factors for atherosclerosis. In the linear regression analyses, age and the number of decayed surfaces per tooth were identified as influencing factors associated with a higher atherosclerotic burden, and the number of restorations per tooth was associated with a lower atherosclerotic burden. CONCLUSION: Dental caries, pulpal caries, and chronic apical periodontitis are associated positively, while restorations are associated inversely, with aortic atherosclerotic burden. Prospective studies are required to confirm these observations and answer the question of possible causality.

The occurrence of dental caries is associated with atherosclerosis

OBJECTIVE: Previous studies have suggested that marginal periodontitis is a risk factor for developing atherosclerosis. The objective of this study was to determine whether caries may also be associated with atherosclerosis. METHODS: The computed tomography data sets of 292 consecutive patients, 137 women and 155 men with a mean age of 54.1±17.3 years, were analyzed. Caries were quantified based on the number of decayed surfaces of all the teeth, and periodontitis was quantified on the basis of the horizontal bone loss in the jaw. The presence of chronic apical periodontitis (CAP) was assessed, and the aortic atherosclerotic burden was quantified using a calcium scoring method. RESULTS: The patients with <1 caries surfaces/tooth had a lower atherosclerotic burden (0.13±0.61 mL) than patients with ≥1 caries surfaces/tooth. The atherosclerotic burden was greater in patients with a higher number of lesions with pulpal involvement and more teeth with chronic apical periodontitis. In the logistical regression models, age (Wald 49.3), number of caries per tooth (Wald 26.4), periodontitis (Wald 8.6), and male gender (Wald 11) were found to be independent risk factors for atherosclerosis. In the linear regression analyses, age and the number of decayed surfaces per tooth were identified as influencing factors associated with a higher atherosclerotic burden, and the number of restorations per tooth was associated with a lower atherosclerotic burden. CONCLUSION: Dental caries, pulpal caries, and chronic apical periodontitis are associated positively, while restorations are associated inversely, with aortic atherosclerotic burden. Prospective studies are required to confirm these observations and answer the question of possible causality. .

Resonance frequency analysis: a new diagnostic tool for dental ankylosis.

Ankylosed teeth are considered in orthodontic treatment planning; however, diagnostic tools to quantify the rigidity of the tooth-to-bone connection are rare. Resonance frequency analysis (RFA) can quantify the rigidity of the dental implant-to-bone connection and thus may serve as a potential diagnostic tool to identify ankylosed teeth. To test this assumption, we examined 15 and 30 primary mandibular molars, with and without clinical signs of ankylosis, using the Osstell Mentor system. A cut-off implant stability quotient (ISQ) of 43 provided a specificity of 100% and a sensitivity of 53.3% when measured in the mesio-distal direction or a sensitivity of 20% when measured in the bucco-lingual direction. Based on a receiver-operating characteristic (ROC), the area under the curve (AUC) of 0.807 showed the mesio-distal direction of measurement to be a test of moderate discriminatory power. Given its non-invasiveness, RFA may serve as a quantitative diagnostic supplement to the clinical examination of potentially ankylosed primary molars.

Cephalometric variables discriminate among magnetic resonance imaging-based structural characteristic groups of the temporomandibular joint.

OBJECTIVE: The aim of this study was to assess retrospectively whether, in patients with temporomandibular joint (TMJ) arthralgia, commonly used cephalometric variables of dentofacial morphology can discriminate among magnetic resonanace imaging (MRI)-based TMJ structural characteristic groups of "uni- or bilateral disc displacement without reduction (DDwoR) associated with bilateral osteoarthrosis (OA)" and "uni- or bilateral disc displacement with reduction (DDwR) without OA." STUDY DESIGN: Bilateral MRI of the TMJ was performed in 56 consecutive TMJ arthralgia patients to identify individuals with specific structural characteristic of uni- or bilateral TMJ DDwoR, DDwR, and OA. Application of the criteria resulted in a study group of 31 patients with "uni- or bilateral DDwoR with bilateral OA" and 25 with "uni- or bilateral DDwR without OA." Linear and angular cephalometric measurements were taken from lateral cephalograms to apply selected criteria of dentofacial morphology. One-way analysis of variance was used to assess differences in cephalometric variables by MRI-based TMJ group. Then, discriminant function analysis predicted TMJ group membership. RESULTS: A-B plane to facial plane angle, palatal plane to occlual plane, and interincisal angle produced a significantly discriminant function that predicted TMJ group membership (P < .001). This function correctly classified 85.7% of original grouped cases. CONCLUSIONS: Cephalometric variables may discriminate among MRI-based TMJ structural characteristic groups. Additional diagnostic information related to MRI-based classification groups was generated.

Are temporomandibular joint disk displacements without reduction and osteoarthrosis important determinants of mandibular backward positioning and clockwise rotation?

OBJECTIVE: The aim of this study was to estimate whether, in patients with temporomandibular joint (TMJ) arthralgia, the magnetic resonanace imaging (MRI) findings of bilateral TMJ disk displacement without reduction (DDwoR) and/or osteoarthrosis (OA) are determinants of mandibular backward positioning and/or clockwise rotation. STUDY DESIGN: Bilateral MRI of the TMJ was performed in 50 consecutive TMJ arthralgia patients to identify individuals with bilateral TMJ DDwoR and/or OA. Linear and angular cephalometric measurements were taken to apply selected criteria of mandibular backward positioning (FH to Na-Pog <84°, Na-A-Pog >5°, and SNB <75°) and clockwise rotation (FH to OP >13°, MP to FH >35°, and S-Gn to FH >64°). Logistic regression analysis was used to estimate the association between selected MRI and cephalometric parameters. RESULTS: In the age- and gender-adjusted analyses, significant increases in risk of mandibular backward positioning and clockwise rotation occurred with bilateral DDwoR and OA (9.5:1; P = .040). CONCLUSION: In patients with TMJ arthralgia the MRI parameters of DDwoR and OA seem to be important determinants of mandibular backward positioning and clockwise rotation.

Miniscrews in orthodontic treatment: review and analysis of published clinical trials.

INTRODUCTION: A systematic review of effects related to patient, screw, surgery, and loading on the stability of miniscrews was conducted. METHODS: Reports of clinical trials published before September 2007 with at least 30 miniscrews were reviewed. Parameters examined were patient sex and age, location and method of screw placement, screw length and diameter, time, and amount of loading. RESULTS: Fourteen clinical trials included 452 patients and 1519 screws. The mean overall success rate was 83.8% + or - 7.4%. Patient sex showed no significant differences. In terms of age, 1 of 5 studies with patients over 30 years of age showed a significant difference (P <0.05). Screw diameters of 1 to 1.1 mm yielded significantly lower success rates than those of 1.5 to 2.3 mm. One study reported significantly lower success rates for 6-mm vs 8-mm long miniscrews (72% vs 90%). Screw placement with or without a surgical flap showed contradictory results between studies. Three studies showed significantly higher success rates for maxillary than for mandibular screws. Loading and healing period were not significant in the miniscrews' success rates. CONCLUSIONS: All 14 articles described success rates sufficient for orthodontic treatment. Placement protocols varied markedly. Screws under 8 mm in length and 1.2 mm in diameter should be avoided. Immediate or early loading up to 200 cN was adequate and showed no significant influence on screw stability.

Osseointegration of a subperiosteal anchoring device in the minipig mandible.

INTRODUCTION: Onplants serve as subperiosteal anchorage in the maxilla to facilitate tooth movement. We determined the applicability of onplants and the process of osseointegration in the mandible of minipigs. METHODS: Thirty-six onplants (OnPlants, Nobel Biocare USA, Yorba Linda, Calif) were positioned in 9 adult animals, 2 on each side. At 3, 6, and 12 weeks after surgery, 3 minipigs were killed. Undecalcified ground sections were evaluated histologically and histomorphometrically. RESULTS: Nineteen onplants were lost during the observation period. Newly formed bone per tissue volume was 7% +/- 5% (n = 4), 21% +/- 9% (n = 5), and 22% +/- 13% (n = 8) at the 3 observation times. The corresponding percentages of bone-to-implant contact were 15% +/- 22%, 30% +/- 27%, and 44% +/- 35%. The number of bone-to-implant contacts remained stable over time at 1.0 +/- 0.9 contacts per millimeter. The average lengths of bone-to-implant contacts were 0.2 +/- 0.1 mm, 0.3 +/- 0.2 mm, and 0.5 +/- 0.3 mm. CONCLUSIONS: These results showed a low survival rate of onplants in the mandible and that the early stage of healing is central to the process of osseointegration. Stable placement is a prerequisite for onplant survival in the mandible.

Sagittal and vertical load-deflection and permanent deformation of transpalatal arches connected with palatal implants: an in-vitro study.

INTRODUCTION: The purposes of this laboratory investigation were to (1) measure the sagittal and vertical deflection of loaded transpalatal arches (TPAs) connected to a palatal implant, (2) measure the extent of permanent deformation of the connecting TPA in the sagittal and vertical directions, (3) test various wire dimensions in terms of deflection behavior, and (4) evaluate soldering vs laser welding vs adhesive bonding of TPAs in terms of load deflection behavior. METHODS: Stainless steel wires of 6 dimensions were tested: 0.8 x 0.8, 0.9, 1, 1.1, 1.2, and 1.2 x 1.2 mm. For each dimension, 10 specimens were soldered to the palatal implant abutment, 10 were laser welded, and 10 were adhesively bonded to the implant abutment (total, 180 specimens). The measuring device applied increments of force of 50 cN, from 0 to 500 cN. Then the specimens were unloaded. The values were statistically described and analyzed with ANOVA and Wilcoxon rank sum tests. RESULTS AND CONCLUSIONS: Absolute orthodontic anchorage without deformation of TPAs was not observed with the wire dimensions tested. To prevent loss of anchorage greater than 370 mum (sagittal deflection of 1.2 x 1.2 mm adhesively bonded TPA at 500 cN force level), wires thicker than 1.2 x 1.2 mm or cast anchorage elements must be considered for clinical practice. However, larger cross sections might cause more patient discomfort, and laboratory procedures increase costs.