Objectives/aim To analyze and compare costs of different prosthetic rehabilitations for the edentulous maxilla. Materials and methods Patients with edentulous maxillae were rehabilitated with either of three implant-supported prosthetic protocols; removable overdenture supported by 2 implants (ISOD 2), fixed dental prostheses supported by 4 (ISFAFDP 4) or 6 (ISFAFDP 6) implants. Cost of treatment and costs during follow-up were registered and compared. Results Twenty-four patients were included: six patients received ISOD 2 treatment, eight patients received ISFADP 4 treatment and ten patients received ISFADP 6 treatment. Initial costs for ISFAFDP 6 were higher than costs for ISFAFDP 4 and ISOD 2, but there were no differences in cost for maintenance i.e., the ISOD treatment remained the least costly treatment alternative after 1-year follow-up. Discussion The lack of difference in cost for maintenance and repair over the first year suggests that implant-supported overdentures will remain the least costly treatment option for the edentulous maxilla, at least in a short-term perspective. Conclusions Removable maxillary overdentures supported by 2 implants may be a valid low cost treatment option.

Objectives: To evaluate the costs of quad-helix (QH) and removable expansion plate (EP) treatments performed either in specialist or general dentistry for the correction of unilateral posterior crossbite with functional shift in the mixed dentition. Trial design: Four-arm parallel group multicentre randomized controlled trial. Materials and methods: One hundred and ten patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 20 and into the following four groups: QH treatments in specialist orthodontic clinics (QHS), QH treatments in general dentistry (QHG), EP treatments in specialist orthodontic clinics (EPS), and EP treatments in general dentistry (EPG). Blinding was accomplished of the outcome assessor and data analyst. A cost analysis was performed with reference to intention-to-treat (ITT), regarding direct costs, indirect costs, and societal costs (the sum of direct and indirect costs) for calculations of successful treatments alone and for retreatments when required. To determine which alternative has the lower cost, a cost-minimization analysis was undertaken, based on that the outcome of the treatment alternatives were broadly equivalent, so the difference between them reduces to a comparison of costs. Results: In the QHS group, 28 of 28 patients were successfully corrected compared to 23 of 27 in the QHG group. Treatment with expansion plate was less successful: 18 of 27 patients in the EPS group and 18 of 28 in the EPG group. QH treatment performed in specialist orthodontic clinics had significantly lower costs than QH or EP treatment accomplished in general dentistry as well as EP treatments in specialist orthodontic clinics. Limitations: Costs depend on local factors and should not be directly extrapolated to other locations. Conclusion: Treatment of unilateral posterior crossbite in the mixed dentition is recommended to be performed by a specialist orthodontist using the QH appliance. Trial registration: The trial was not registered.

OBJECTIVES: The objectives of this study were to assess the three-dimensional (3D) treatment changes (palatal surface area and volume) of forced unilateral posterior crossbite correction using either quad-helix or removable expansion plate appliances in the mixed dentition, and to compare the treatment changes with the three-dimensional changes occurring in age-matched untreated unilateral posterior crossbite patients as well as in subjects with normal occlusion and with no or mild orthodontic treatment need. TRIAL DESIGN: Six-arm parallel group multicentre randomized controlled trial. MATERIALS AND METHODS: One-hundred and thirty-five patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 25, and the patients were randomized into the following five groups: quad-helix treatments in specialist orthodontic clinics (QHS), quad-helix treatments in general dentistry (QHG), removable expansion plate treatments in specialist orthodontic clinics (EPS), removable expansion plate treatments in general dentistry (EPG), and untreated crossbite (UC). Twenty-five patients with normal occlusion who served as normal controls were also included in the trial. Blinding of the outcome assessor and data analyst was accomplished. Data on all children were evaluated on an intention-to-treat basis, regarding 3D palatal surface area, palatal projection area, and palatal shell volume; two-dimensional linear measurements were registered at the same time. RESULTS: After treatment, the surface and projection area and shell volume increased in the four treatment groups (QHS, QHG, EPS, and EPG). QHS increased significantly more than EPG for the surface and projection area. The QHS and EPS had significantly higher mean difference for shell volume. LIMITATIONS: The trial considers a short-term evaluation. CONCLUSION: After treatment, there were no significant differences between the four treatment groups and the normal group, which implies that the surface and projection area together with the shell volume for the four treatment groups and the normal group were equivalent. TRIAL REGISTRATION: The trial was registered with https://www.researchweb.org/is/sverige, registration number: 220751.

Objective: To analyse cost-effectiveness of anchorage reinforcement with buccal miniscrews and with molar blocks. We hypothesized that anchorage with miniscrews is more cost-effective than anchorage with molar blocks. Trial design: A single-centre, two-arm parallel-group randomized controlled trial. Methods: Adolescents (age 11–19 years) in need of treatment with fixed appliance, premolar extractions, and en masse retraction were recruited from one Public Dental Health specialist centre. The intervention arm received anchorage reinforcement with buccal miniscrews during space closure. The active comparator received anchorage reinforcement with molar blocks during levelling/alignment and space closure. The primary outcome measure was societal costs defined as the sum of direct and indirect costs. Randomization was conducted as simple randomization stratified on gender. The patients, caregivers, and outcome assessors were not blinded. Results: Eighty patients were randomized into two groups. The trial is completed. All patients were included in the intention-to-treat analysis. The median societal costs for the miniscrew group were €4681 and for the molar block group were €3609. The median of the difference was €825 (95% confidence interval (CI) 431–1267). This difference was mainly caused by significantly higher direct costs consisting of material and chair time costs. Differences in chair time costs were related to longer treatment duration. No serious harms were detected, one screw fractured during insertion and three screws were lost during treatment. Generalizability and limitations: The monetary variables are calculated based on a number of local factors and assumptions and cannot necessarily be transferred to other countries. Variables such as chair time, number of appointments, and treatment duration are generalizable. Owing to the study protocol, the benefit of miniscrews as a stable anchorage has not been fully utilized. Conclusions: When only moderate anchorage reinforcement is needed, miniscrews are less cost-effective than molar blocks. The initial hypothesis was rejected. Miniscrews provide better anchorage reinforcement at a higher price. They should be used in cases where anchorage loss cannot be accepted. Trial registration: NCT02644811

Objective: To examine: (I) the current evidence of the impact of fixed orthodontic appliances on the development of halitosis in patients undergoing orthodontic treatment, and (II) the influence of different orthodontic bracket systems on halitosis. Material and methods: Three electronic databases (PubMed, Scopus, and Cochrane Library) were searched prior to March 15, 2018. The review was systematically conducted and reported according to the Cochrane Handbook and the PRISMA statement. Only Randomised Clinical Trials (RCTs) were considered. Selected full-text papers were independently assessed by four investigators and any disagreements were resolved by consensus. The Cochrane Handbook was used to grade the risk of bias and the quality of evidence was rated according to GRADE. Results: Out of 363 identified studies, three RCTs on halitosis and fixed orthodontic appliances met the inclusion criteria. The risk of bias in the three studies was rated as high and the quality of evidence was rated as very low. Conclusions/clinical implications: There is a lack of scientific evidence that subjects with fixed orthodontic appliances develop halitosis during treatment. Additional well-conducted RCTs with extended periods of assessment are needed as well as consensus concerning cut-off values for the diagnosis of halitosis.

Objectives: To compare Oral health-related quality of life (OHRQoL) among 9-year-old children with excessive overjet (EO) to children with unilateral posterior crossbite (UPC) and children with normal occlusion (NO). Materials and methods: The study sample sourced from 19 Public Dental Service Clinics in Sweden. Reported are baseline data originating from two controlled trials, one regarding UPC and the other focusing on EO. The NO children derive from the same trials. The UPC group comprised 93 children (45 boys and 48 girls), the EO group 71 children (36 boys and 35 girls), and the NO group 65 children (32 boys and 33 girls). In conjunction to a clinical examination, all children completed the Child Perceptions Questionnaire (CPQ8-10) for evaluation of OHRQoL. The CPQ8-10 comprises 25 questions grouped into four domains: oral symptoms, functional limitations, emotional, and social well-being. Validated questions about pain in the jaws and face were also included. Results: The total mean CPQ score was 5.1 for the UPC, 7.4 for the EO, and 4.4 for the NO group, showing a significant difference between the UPC and EO (P = 0.048) and between EO and NO group (P = 0.012). These differences remained when adjusted for the confounders' caries, trauma, enamel defects, and headache. No difference between UPC and NO was found. The EO children also reported significantly higher scores in the domains emotional and social well-being (P = 0.039 and P = 0.012). Limitations: The study would be strengthened if a longitudinal design had been performed. Conclusion: Children with EO reported significantly lower OHRQoL compared to children with UPC or NO. The children generally reported low CPQ scores that imply an overall fairly good OHRQoL.

OBJECTIVE: Economic evaluations provide an important basis for allocation of resources and health services planning. The aim of this study was to evaluate and compare the costs of correcting anterior crossbite with functional shift, using fixed or removable appliances (FA or RA) and to relate the costs to the effects, using cost-minimization analysis. DESIGN, SETTING, AND PARTICIPANTS: Sixty-two patients with anterior crossbite and functional shift were randomized in blocks of 10. Thirty-one patients were randomized to be treated with brackets and arch wire (FA) and 31 with an acrylic plate (RA). Duration of treatment and number and estimated length of appointments and cancellations were registered. Direct costs (premises, staff salaries, material, and laboratory costs) and indirect costs (the accompanying parents' loss of income while absent from work) were calculated and evaluated with reference to successful outcome alone, to successful and unsuccessful outcomes and to re-treatment when required. Societal costs were defined as the sum of direct and indirect costs. INTERVENTIONS: Treatment with FA or RA. RESULTS: There were no significant differences between FA and RA with respect to direct costs for treatment time, but both indirect costs and direct costs for material were significantly lower for FA. The total societal costs were lower for FA than for RA. LIMITATIONS: Costs depend on local factors and should not be directly extrapolated to other locations. CONCLUSION: The analysis disclosed significant economic benefits for FA over RA. Even when only successful outcomes were assessed, treatment with RA was more expensive. TRIAL REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement.

Background: Recently low-level laser therapy (LLLT) has been proposed to improve orthodontic treatment. The aims of this systematic review were to investigate the scientific evidence to support applications of LLLT: (a) to accelerate tooth movement, (b) to prevent orthodontic relapse and (c) to modulate acute pain, during treatment with fixed appliances in children and young adults. Methods: To ensure a systematic literature approach, this systematic review was conducted to Goodman's four step model. Three databases were searched (Medline, Cochrane Controlled Clinical Trials Register and Scitation), using predetermined search terms. The quality of evidence was rated according to the GRADE system Results: The search identified 244 articles, 16 of which fulfilled the inclusion criteria: three on acceleration of tooth movement by LLLT and 13 on LLLT modulation of acute pain. No study on LLLT for prevention of relapse was identified. The selected studies reported promising results for LLLT; elevated acceleration of tooth movement and lower pain scores, than controls. With respect to method, there were wide variations in type of laser techniques Conclusions: The quality of evidence supporting LLLT to accelerate orthodontic tooth movement is very low and low with respect to modulate acute pain. No studies met the inclusion criteria for evaluating LLLT to limit relapse. The results highlight the need for high quality research, with consistency in study design, to determine whether LLLT can enhance fixed appliance treatment in children and young adults.

Background: Economic evaluation is assuming increasing importance as an integral component of health services research. Aim: To conduct a systematic review of the literature and assess the evidence from studies presenting orthodontic treatment outcomes and the related costs. Materials/methods: The literature review was conducted in four steps, according to Goodman’s model, in order to identify all studies evaluating economic aspects of orthodontic interventions. The search covered the databases Medline, Cinahl, Cochrane, Embase, Google Scholar, National Health Service Economic Evaluation Database, and SCOPUS, for the period from 1966 to September 2014. The inclusion criteria were as follows: randomized controlled trials or controlled clinical trials comparing at least two different orthodontic interventions, evaluation of both economic and orthodontic outcomes, and study populations of all ages. The quality of each included study was assessed as limited, moderate, or high. The overall evidence was assessed according to the GRADE system (The Grading of Recommendations Assessment, Development and Evaluation). Results: The applied terms for searches yielded 1838 studies, of which 989 were excluded as duplicates. Application of the inclusion and exclusion criteria identified 26 eligible studies for which the full-text versions were retrieved and scrutinized. At the final analysis, eight studies remained. Three studies were based on cost-effectiveness analyses and the other five on cost-minimization analysis. Two of the cost-minimization studies included a societal perspective, i.e. the sum of direct and indirect costs. The aims of most of the studies varied widely and of studies comparing equivalent treatment methods, few were of sufficiently high study quality. Thus, the literature to date provides an inadequate evidence base for economic aspects of orthodontic treatment. Conclusion: This systematic review disclosed that few orthodontic studies have presented both economic and clinical outcomes.There is currently insufficient evidence available about the health economics of orthodontic interventions. Further investigation is warranted.

Objective: Comparison of three different retention strategies 5 years or more postretention. Design, Setting, and Participants: Randomized, prospective, single-centre controlled trial. Forty-nine patients (33 girls and 16 boys) were randomly assigned to one of three retention methods during 2 years by picking a ballot shortly before start of retention treatment. Inclusion criteria were no previous orthodontics, permanent dentition, normal skeletal sagittal, vertical, and transversal relationships, Class I dental relationship, space deficiencies, treatment plan with extractions of four premolars followed by fixed straight-wire appliance. Maxillary and mandibular Little's irregularity index (LII), intercanine and intermolar width, arch length, and overbite/overjet were recorded in a blinded manner, altogether 10 measurements on each patient. Significant differences in means within groups assessed by t-test and between groups by one-way analysis of variance. Interventions: Retention methods: removable vacuum-formed retainer (VFR) covering the palate and the maxillary anterior teeth from canine-to-canine and bonded canine-to-canine retainer in the lower arch (group V-CTC); maxillary VFR combined with stripping of the lower anterior teeth (group V-S); and prefabricated positioner (group P). Results: Maxillary mean LII ranged from 1.8 to 2.6 mm, mean intercanine width 33.6-35.3 mm with a significant difference between groups V-S and P, mean intermolar width 46.8-47.4 mm and mean arch length 21.8-22.8 mm. Mandibular mean LII ranged from 2.0 to 3.4 mm with a significant difference between groups V-S and P, mean intercanine width from 25.4 to 26.6 mm, mean intermolar width from 40.8 to 40.9 mm and mean arch length from 16.9 to 17.3 mm. Mean overbite ranged from 1.8 to 2.7 mm and mean overjet from 3.7 to 4.1 mm. Limitations: A single centre study could be less generalizable. Conclusions: The three retention methods disclosed equally favourable clinical results.

SUMMARY BACKGROUND: There are few cost evaluation studies of orthodontic retention treatment. The aim of this study was to compare the costs in a randomized controlled trial of three retention methods during 2 years of retention treatment. MATERIALS/METHODS: To determine which alternative has the lower cost, a cost-minimization analysis (CMA) was undertaken, based on that the outcome of the treatment alternatives was equivalent. The study comprised 75 patients in 3 groups consisting of 25 each. The first group had a vacuum-formed retainer (VFR) in the maxilla and a cuspid retainer in the mandible (group V-CTC), the second group had a VFR in the maxilla combined with stripping of the incisors and cuspids in the mandible (group V-S), and the third group had a prefabricated positioner (group P). Direct cost (premises, staff salaries, material and laboratory costs) and indirect costs (loss of time at school) were calculated. Societal costs were defined as the sum of direct and indirect costs. RESULTS: The societal costs/patient for scheduled appointments for 2 years of retention treatment in group V-CTC were €497, group V-S €451 and group P €420. Societal costs for unscheduled appointments in group V-CTC were €807 and in group V-S €303. In group P, there were no unscheduled appointments. CONCLUSIONS/IMPLICATIONS: After 2 years of retention in compliant patients, the cuspid retainer was the least cost-effective retention appliance. The CMA showed that for a clinically similar result, there were differences in societal costs, but treatment decisions should always be performed on an individual basis.

There are few cost evaluation studies of orthodontic treatment. The aim of this study was to determine the costs of correcting posterior crossbites with Quad Helix (QH) or expansion plates (EPs) and to relate the costs to the effects. To determine which alternative has the lower cost, a cost-minimization analysis was undertaken, based on that the outcome of the treatment alternatives is identical. The study comprised 40 subjects in the mixed dentition, who had undergone treatment for unilateral posterior crossbite: 20 with QH and 20 with EPs. Duration of treatment, number of appointments, broken appointments, and cancellations were registered. Direct costs (for the premises, staff salaries, material and laboratory costs) and indirect costs (loss of income due to parent's assumed absence from work) were calculated and evaluated for successful treatment alone, for successful and unsuccessful treatment and re-treatment when required. The QH had significantly lower direct and indirect costs, with fewer failures requiring re-treatment. Even the costs for successful cases only were significantly lower in the QH than in the EP group. The results clearly show that in terms of cost-minimization, QH is the preferred method for correcting posterior crossbite in the mixed dentition.

Syftet med arbetet var att skapa översikt av metoder och substanser för ”farmakologisk retention” efter ortodontisk behandling via injicering lokalt eller systemiskt samt undersöka kvalitén i dessa studier. Substanserna som undersöktes var Bisphosphonat, Relaxin, Bone morphogenetic protein (BMP), Anti-VEGF and Simvastatin. För den systematiska genomgången av litteraturen användes databaserna PubMed/Medline och Cochrane Library . Två personer granskade abstract utifrån inklusions/exklusionskriterier. Sökningen resulterade i 22 studier på djur. Efter inklusion/exklusion kvarstod sju studier som delades upp i lokal respektive systemisk administration. Lokal eller systemisk injicering av farmakologiska substanser visade sig minska recidiv hos försöksdjur där tänder roterats eller tippats. Underlaget är emellertid begränsat och ytterligare forskning krävs. Studier som långsiktigt undersöker substansernas effekt behövs, liksom studier på eventuell systemisk påverkan.

Enkelsidigt korsbett är en av de vanligaste bettavvikelserna i växel-bettet, dvs. i de åldrar då barnets tänder byts ut från mjölktänder till permanenta tänder. Korsbett innebär att överkäkens och un-derkäkens bredd inte passar ihop när man biter samman käkarna. Detta innebär att när patienten skall bita ihop glider underkäken åt sidan och patienten ”biter snett”. Om korsbett inte behandlas finns risk för problem i form av avvikande funktion och smärttillstånd i käkar, ansiktsmuskler och käkleder samt att ansiktet kan bli asymmetriskt.God tandvård innebär att använda effektiva behandlingsmetoder med god långsiktig stabilitet och kostnadseffektivitet. Det över-gripande syftet med denna avhandling var att i växelbettet jämföra och utvärdera olika behandlingsmetoder för att korrigera enkelsi-digt korsbett med avseende på effektivitet, stabilitet och kostnads-effektivitet. För att uppnå ett så högt vetenskapligt underlag som möjligt, utfördes randomiserade, kontrollerade studier (RCT-studier), vilket innebär att patienterna som är med i studien har lottats till respektive behandlingsgrupp. Avhandlingen är baserad på följande studier:Delarbete I är en systematisk litteraturöversikt där den tillgäng-liga vetenskapliga litteraturen avseende behandling av enkelsidigt korsbett utvärderades från ett evidensbaserat perspektiv. Översik-ten omfattade tidsperioden januari 1966 till oktober 2002 och ut-ökades senare till december 2010.Delarbetena II, III and IV är RCT-studier. Delarbete II jämför-de och utvärderade de olika behandlingsstrategierna Quad Helix, expansionsplåt, composituppbyggnad på underkäkens kindtänder samt avvaktande för att invänta eventuell spontan korrektion. Delarbete III analyserade den långsiktiga stabiliteten och föränd-ringarna tre år efter behandling med Quad Helix respektive expan-sionsplåt och jämförelser gjordes med patienter med normalt bett. I delarbete IV utvärderades kostnadseffektiviteten mellan Quad Helix och expansionsplåt genom att utföra en kostnads-minimeringsanalys. Konklusioner i delarbete I, inklusive den kompletterande litte-ratursökningen:•Det finns måttlig evidens för att behandling med Quad Helix är mer effektiv än behandling med avtagbar expansionsplåt. •Det finns begränsad eller otillräcklig evidens för behandlingar-nas stabilitet, effekter på livskvalitet och inverkan på käk- och ansiktsstrukturerna.Konklusioner i delarbete II och III:•Quad Helix är en effektiv behandlingsmetod och är överlägsen expansionsplåten. •Composituppbyggnad på underkäkens kindtänder är inte ef-fektivt för att korrigera enkelsidigt korsbett, och spontan kor-rektion sker ej vid avvaktan/utebliven behandling.•Om korsbettsbehandlingen lyckas, antingen med Quad Helix eller med expansionsplåt, kan man förvänta sig likvärdig lång-siktig stabilitet och prognosen är gynnsam.•Trots aktiv expansion av överkäken på de patienter som tidi-gare hade korsbett uppnåddes aldrig samma vidd i överkäken som hos patienter utan tidigare korsbett (normalpatienterna).Konklusioner i delarbete IV:•Quad Helix är mer kostnadseffektiv än expansionsplåt. •Quad Helix hade lägre direkta och indirekta kostnader och färre misslyckade behandlingar som behövde göras om. •Även när enbart de lyckade behandlingarna räknades var be-handling med expansionsplåt dyrare än Quad Helix. Klinisk betydelse:För att korrigera enkelsidigt korsbett i växelbettet är Quad Helix överlägsen expansionsplåten med avseende på behandlingseffektivi-tet och kostnader och är det primära behandlingsalternativet. Båda behandlingsalternativen, förutsatt att behandlingen lyckas med ex-pansionsplåten, har god långsiktig stabilitet.

INTRODUCTION: The long-term stability of posterior crossbite correction in the mixed dentition has not been sufficiently evaluated. Our aim was to compare long-term outcomes in patients with crossbite correction by using matched controls with normal occlusion.

METHODS: After 35 patients were treated for crossbite with a quad-helix or an expansion plate, we used randomized controlled trial methodology to follow them for 3 years posttreatment. All had fulfilled our pretreatment criteria: mixed dentition, unilateral posterior crossbite, no sucking habits, and no previous orthodontic treatment. Transverse relationships, maxillary and mandibular widths, overbite, overjet, arch lengths, and midlines were registered on the study models immediately before and after treatment and at the follow-up 3 years after treatment. The matched control group comprised 20 subjects with normal occlusion and was compared with the first and last registrations for the treated groups.

RESULTS: At follow-up, changes in the treatment groups were equal and stable. The changes were comparable with the control group. All other changes were minor and had no clinical implications. The long-term effect of crossbite correction on midline deviation was unpredictable.

CONCLUSIONS: If crossbite is successfully corrected by the quad-helix appliance or the expansion plate, similar long-term stability is achieved. However, in treated patients, mean maxillary widths never reached those of normal control subjects.

Stability of Unilateral Posterior Crossbite Correction in the Mixed Dentition - a 3-year Follow-Up. Aim: To compare and evaluate long-term stability of crossbite correction with Quad Helix or expansion plate in the mixed dentition. Methods: In this RCT-study 35 patients with unilateral posterior crossbite were randomized to be treated with either Quad Helix or expansion plate. The inclusion criteria were: mixed dentition, unilateral posterior crossbite, no sucking habits or previous orthodontic treatment. Stability was evaluated after 3 years by study cast measurements. Twenty subjects with normal occlusion were included as controls. Success rate, maxillary and mandibular transverse dimensions, overjet and overbite were registered. Results: Stability was equal for the two treatment methods. Small, albeit significant, differences between the groups were assessed with reference to transverse dimensions. No significant difference was seen for overjet and overbite. Conclusions: The long-term stability of posterior crossbite correction with Quad helix and expansion plate was equal.

Stability of Unilateral Posterior Crossbite Correction in the Mixed Dentition - an RCT-study with 3-year Follow-Up. Aim: To compare and evaluate long-term stability of crossbite correction with Quad Helix or expansion plate in the mixed dentition. Methods: In this RCT-study 35 patients with unilateral posterior crossbite were randomized to be treated with either Quad Helix or expansion plate. The inclusion criteria were: mixed dentition, unilateral posterior crossbite, no sucking habits or previous orthodontic treatment. Stability was evaluated after 3 years by study cast measurements. Twenty subjects with normal occlusion were included as controls. Success rate, maxillary and mandibular transverse dimensions, overjet, overbite and arch length were registered. Results: Stability was equal for the two treatment methods. Small, albeit significant, differences between the groups were assessed with reference to transverse dimensions. No significant difference was seen for overjet and overbite. The treated patients never reached the same transversal width as the normal control group. Conclusions: The long-term stability of posterior crossbite correction with Quad helix and expansion plate was equal. The maxillary width was greater in the control group than the treated groups.

Aim: To compare and evaluate long-term stability of crossbite correction with Quad Helix or expansion plate in the mixed dentition. Methods: In this RCT-study 35 patients with unilateral posterior crossbite were randomized to be treated with either Quad Helix or expansion plate. The inclusion criteria were: mixed dentition, unilateral posterior crossbite, no sucking habits or previous orthodontic treatment. Stability was evaluated after 3 years by study cast measurements. Twenty subjects with normal occlusion were included as controls. Success rate, maxillary and mandibular transverse dimensions, overjet and overbite were registered. Results: Stability was equal for the two treatment methods. Small, albeit significant, differences between the groups were assessed with reference to transverse dimensions. No significant difference was seen for overjet and overbite. Conclusions: The long-term stability of posterior crossbite correction with Quad helix and expansion plate was equal.

INTRODUCTION: From an evidence-based point of view, correction of posterior crossbite is not sufficiently evaluated. Thus, the aims of this study were to compare and evaluate the effectiveness of different treatment strategies to correct unilateral posterior crossbite in the mixed dentition by using the randomized clinical trial methodology with an untreated control group. METHODS: Sixty patients participated in the study. All met the following inclusion criteria: mixed dentition, unilateral posterior crossbite, no sucking habits, and no previous orthodontic treatment. The patients were randomized into 4 groups: quad-helix, expansion plate, composite onlay, and untreated control. The success rates, amounts of maxillary and mandibular expansion, and treatment times were registered. RESULTS: The quad-helix appliance was superior to the expansion plate in success rate and treatment time. Treatment with the expansion plate was unsuccessful in one third of the subjects. Crossbite correction with composite onlay in the mixed dentition was ineffective, and spontaneous correction in the mixed dentition did not occur. CONCLUSIONS: If unilateral posterior crossbite is planned to be corrected in the mixed dentition, this study clearly confirmed that treatment with the quad-helix is an appropriate and successful method.

The aim of this study was to assess the orthodontic treatment effects on unilateral posterior crossbite in the primary and early mixed dentition by systematically reviewing the literature. A literature search was performed by applying the Medline database (Entrez PubMed) and covering the period from January 1966 to October 2002. The inclusion criteria were primary and early mixed dentition with unilateral posterior crossbite, randomized controlled trials (RCT), prospective and retrospective studies with concurrent untreated as well as normal controls, and clinical trials comparing at least two treatment strategies without any untreated or normal group involved. Two reviewers extracted the data independently and also assessed the quality of the studies. The search strategy resulted in 1001 articles, and 12 met the inclusion criteria. Two RCTs of early treatment of crossbite have been performed, and these two studies support grinding as treatment in the primary dentition. There is no scientific evidence available to show which of the treatment modalities, grinding, Quad-helix, expansion plates, or rapid maxillary expansion, is the most effective. Most of the studies have serious problems of lack of power because of small sample size, bias and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods. To obtain reliable scientific evidence, better-controlled RCTs with sufficient ample sizes are needed to determine which treatment is the most effective for early correction of unilateral posterior crossbite. Future studies should also include assessments of long-term stability as well as analysis of costs and side effects of the interventions.