Self-reported pain during different phases of orthodontic treatment with fixed appliance: A multi-centre randomized controlled trial in adolescents with crowding.

OBJECTIVES: To compare self-reported pain levels across various treatment phases using passive self-ligating (Damon) and conventional (Victory) standardized fixed appliance systems. MATERIALS AND METHODS: Adolescents (12-17 years old) with crowding and displaced teeth, planned for non-extraction treatment, were recruited from four orthodontic clinics. They were randomized into stratified blocks (1:1 ratio) using concealed allocation to receive Damon Q™ (34 boys, 28 girls) or Victory™ (39 boys, 31 girls). Pain and analgesic intake were assessed on seven different occasions with validated self-report questionnaires using a 10-grade scale. RESULTS: Of the 132 patients included, six were lost to follow up. Clinically relevant mean pain scores (≥4) were registered in both groups after bonding upper and lower arches and after insertion of 0.019 × 0.025 stainless steel archwire. The highest mean scores were reported on day two after bonding the upper arch (Damon 5.96, Victory 7.18, P = .011). In both groups, at least 40% reported taking analgesics during various treatment phases. The Damon group reported a lower intake of analgesics on days one and two (P = .042 and .037) after treatment initiation. In the entire sample, boys reported significantly higher mean pain scores than girls on the second and third days after bonding (P = .008 and .026, respectively). CONCLUSIONS: Lower pain levels were reported from the Damon group after bonding. In general, boys reported higher pain than girls did. Clinicians and adolescents need to be aware that clinically relevant pain levels can be expected not only after bonding but also in later phases.

Comparisons of costs and treatment effects-an RCT on headgear activator treatment of excessive overjet in the mixed and late mixed dentition.

OBJECTIVES: To compare the costs and treatment effects of headgear activator treatment of Class II malocclusion with excessive overjet between treatments started in the mixed (MD) and late mixed dentition (LMD). TRIAL DESIGN: Two-arm parallel-group single-centre randomized controlled trial (RCT). MATERIAL AND METHODS: A total of 56 children presenting Class II malocclusion with excessive overjet were assessed and invited to an RCT designed as intention-to-treat. The children were randomized, by an independent person not involved in the trial into two groups, treatment with headgear activator in the MD starting at the age of 9 or to treatment with a headgear activator in LMD, starting at the age of 11. The primary outcome measure was to compare the treatment costs between the two groups. Societal costs (the sum of direct and indirect costs) were calculated for successful treatments only and when unsuccessful treatments were included. Secondary outcomes were comparisons of oral health-related quality of life (OHRQoL), dental and skeletal treatment effects, lip closure, and trauma incidence. Data collections were performed before and after treatment, corresponding to a treatment period of 2 years. Blinding was accomplished when assessing outcomes. RESULTS: No group differences in costs were found of successful treatments or when unsuccessful treatments were included. The most pronounced treatment effects in both groups were the reduction of overjet and improved molar relation. Treatment started in MD or in LMD were equal and without significant differences regarding effects on OHRQoL, skeletal effects, lip closure, and incidence of trauma. HARMS: No harm was observed, but 8 of 30 children (27%) in the MD and 6 of 21 children (29%) in the LMD group showed unsuccessful results. LIMITATIONS: Costs depend on local factors and can thereby not be directly transferred to other settings. It was a single-centre trial and can thus be less generalizable. CONCLUSIONS: Regarding costs and treatment effects, there is no difference if headgear activator treatment of excessive overjet starts in the MD or LMD. CLINICAL TRIAL REGISTRATION: NCT04508322.

Do preterm-born adolescents have a poorer oral health-related quality of life?

BACKGROUND: To evaluate oral health-related quality of life (OHRQoL) over a period of five years using the Oral Health Impact Profile (OHIP-14) questionnaire in a population of Swedish adolescents born preterm and full term. METHODS: In a longitudinal study of adolescents aged 12-14 and 17-19, changes over time in OHRQoL were measured by using OHIP-14. The OHIP-14 score, self-reported chronic illness, temporomandibular disorder (TMD pain) and subjective orthodontic treatment need were compared between 98 extremely and very preterm born (< 32 gestational week) and 93 full-term controls (≥ 37 gestational week) at two ages. The chi-square test was used for comparisons within the extremely-, very-, and full-term control groups, and to contrast the differences of mean scores of OHIP-14, the ANOVA test was used for comparisons within the study groups of extremely preterm, very preterm and full term-born adolescents. RESULTS: All adolescents reported a good self-perceived OHRQoL. No significant differences in the comparisons of the total mean scores were revealed between the groups, between gender or in domain-specific scores over the 5-year period. Very preterm adolescents with reported chronic illness at 12-14 years of age showed significantly higher mean scores of OHIP-14 compared with those without chronic illness (p = 0.015). At age 17-19, significantly higher mean scores of OHIP-14 were reported by very preterm adolescents with TMD pain compared to those without TMD pain (p = 0.024). Significantly higher mean scores of OHIP-14 were found among the extremely preterm (p = 0.011) and very preterm born adolescents (p = 0.031) with a subjective need of orthodontic treatment compared with those without orthodontic treatment need. CONCLUSIONS: Poor OHRQoL measured with OHIP-14 in very preterm adolescents aged 12-14 was related to chronic illness and aged 17-19 to TMD pain. In addition, extremely and very preterm-born adolescents with subjective orthodontic treatment need at 17-19 years of age also reported poor OHRQoL. To improve the dentist-patient relationship and achieve more successful treatment results, it is important for dental clinicians to understand the impact that chronic illness, TMD pain and orthodontic treatment need has on OHRQoL in preterm-born adolescents.

Early headgear activator treatment of Class II malocclusion with excessive overjet: a randomized controlled trial.

OBJECTIVES: To compare early headgear activator treatment of Class II malocclusion with excessive overjet with untreated control subjects in terms of the primary outcomes overjet and overbite as well as the effect regarding oral-health-related quality of life (OHRQoL), lip closure, incidence of trauma, and skeletal changes. TRIAL DESIGN: Two-arm parallel group single-centre randomized controlled trial. MATERIAL AND METHODS: A total of 60 children (mean age 9.5 years) presenting a Class II malocclusion with excessive overjet were recruited. The trial was designed as intention-to-treat and the participants randomized by an independent person not involved in the trial to either early treatment with headgear activator or to an untreated control group (UG). Dental and skeletal variables as well as registrations of OHRQoL, lip closure, and incidence of trauma were recorded. For the treatment group, data were registered at baseline before treatment and when treatment was finished, corresponding to approximately 2 years. For the UG, registrations were made at baseline and at 11 years of age. Observers were blinded to treatment allocation when assessing outcomes. RESULTS: Early treatment with headgear activator significantly decreased overjet and improved molar relationship when compared with untreated controls. The effects were primarily due to dentoalveolar changes. Early treatment had no evident effect regarding OHRQoL, lip closure, or incidence of trauma. Lack of cooperation resulted in unsuccessful treatments for 27% of the patients. LIMITATIONS: The trial was a single-centre trial and can thus be less generalizable. CONCLUSIONS: The main treatment effect of early headgear activator treatment of Class II malocclusion with excessive overjet is reduction of overjet. TRIAL REGISTRATION: NCT04508322.

A tool for assessment of risk of bias in studies of adverse effects of orthodontic treatment applied in a systematic review on external root resorption.

BACKGROUND AND AIMS: Systematic reviews (SRs) are considered to provide reliable estimates, but flaws in designs, methods of monitoring effects, and outcomes have the potential to bias results. There are several tools for assessing risk of bias (RoB), most of them designed for SRs of beneficial effects. To our knowledge, there is no tool that is adapted specifically to assess RoB in studies of adverse effects associated with orthodontic treatment. To address this, the aim of this study was first to introduce a tool for assessment of RoB in studies of adverse effects associated with orthodontic treatment and, second, to apply it in an SR of external root resorption (ERR) associated with orthodontic treatment with fixed appliance. MATERIALS AND METHODS: The approach with domains supported by signalling questions was used for the tool. Domains and signalling questions were tailored to the review questions of the SR of studies of ERR after orthodontic treatment using periapical radiography or cone beam computed tomography. Duplicate study selection, data extraction, and RoB assessment using the tool, followed by meta-analyses, were performed. RESULTS: Using the tool for the assessment of RoB identified shortcomings and report deficiencies of primary studies concerning the presentation of orthodontic treatment, identification of ERR, and analysis of outcomes. RoB assessment resulted in 12 of 32 studies read in full text being included. Reported severe ERR varied across studies between 2 and 14 per cent for all incisors and 10 and 29 per cent for maxillary incisors. Results of ERR related to patients' age and sex, orthodontic diagnosis, and treatment were contradictory. Quality of evidence evaluated by GRADE was low due to study limitations, imprecision, and inconsistency of study results. CONCLUSIONS: As the tool and its application highlight important issues to consider when planning, conducting, and reporting research, the tool may have a valuable role for quality enhancement of future studies of outcomes of orthodontic treatment. The tool may also serve for authors when planning SRs. Our SR identified a need for studies that use rigorous methodology and transparent reporting. REGISTRATION: PROSPERO (ID = CRD42018084725).

Do fixed orthodontic appliances cause halitosis? A systematic review.

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.

Measurability and reliability of assessments of root length and marginal bone level in cone beam CT and intraoral radiography: a study of adolescents.

OBJECTIVES: To evaluate measurability and reliability of measurements of root length and marginal bone level in CBCT, periapical (PA) and bitewing (BW) radiographs. METHODS: CBCT of both jaws, PA of maxillary incisors and posterior BW radiographs of 10 adolescents (mean age 13.4) were selected. The radiographs comprised part of the baseline examinations of a trial of orthodontic treatment. Six raters assessed measurability and measured root length and marginal bone level. Three raters repeated their assessments. Measurability was expressed as frequency of interpretable sites and reliability as intraclass correlation coefficient (ICC). RESULTS: Measurability was 100 % in CBCT and 95 % in PA of maxillary incisors for root length measurements. For marginal bone level, measurability was 100 % in CBCT, 76 % in PA and 86 % in posterior BW. Mean ICC for interrater reliability for root length measurements in CBCT was 0.88 (range 0.27-0.96 among different teeth) and 0.69 in PA of maxillary incisors. For marginal bone level measurements, mean ICC was 0.4 in CBCT, 0.38 in PA of maxillary incisors and 0.4 in posterior BW. Intrarater reliability varied among methods, root length or marginal bone level and among raters, except for root length measurements in CBCT, which presented high reliability (above 0.8) for all raters. CONCLUSIONS: As measurability and reliability were high for root length measurements in CBCT, this may be the method of choice for scientific analyses in orthodontics. For clinical praxis, we recommend PA following the "as low as diagnostically acceptable" principle, as clinical decisions seem to be influenced only when severe root resorption occurs.

The impact of premature birth on dental maturation in the permanent dentition.

OBJECTIVES: To evaluate tooth development and calculate dental maturity score in prematurely born children and to compare the findings with full-term born children. MATERIAL AND METHODS: Nine-year-old preterm children were selected from the Swedish Medical Birth Register. One group consisted of 36 extremely preterm children (born before week 29), and the other included 38 very preterm children (born during weeks 29 to 32). Panoramic radiography was performed on each child and the preterm children were compared with 42 full-term born children. Five observers independently assessed the tooth development stages for all teeth in the left mandible (31-37) on the panoramic radiographs according to the method described by Demirjian et al. (Hum Biol 45:211-227, 1973). Data from tooth development stages were compiled and converted into a dental maturity score for each group. Kappa values were calculated for intra- and inter-observer agreement. RESULTS: When the different development stages for each individual tooth were compared, all observers presented a significant delay in the maturity of tooth 37 for the extremely preterm group (p ≤ 0.002). The extremely preterm group had a significantly lower dental maturity score than the full-term group, as assessed by each observer (p ≤ 0.006). Kappa values for inter-observer agreement varied between 0.31 and 0.71 depending on tooth and intra-observer agreement was between 0.16 and 1.0. CONCLUSIONS: At age 9, the extremely preterm children had a general delay in tooth development. CLINICAL RELEVANCE: The increased survival rate of extremely preterm babies adds a new group of children to society. Dental clinicians should be aware that the delay in tooth development could impact the timing of orthodontic diagnostics and potential treatment.

Oral health-related quality of life among children with excessive overjet or unilateral posterior crossbite with functional shift compared to children with no or mild orthodontic treatment need.

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.

Developmental defects of enamel in the deciduous incisors of infants born preterm: Prospective cohort.

OBJECTIVE: Developmental defects of enamel (DDE) in preterm infants still require clarification and may favour dental caries, lower food intake and greater difficulty with weight-height gain. We evaluated factors associated with DDE in preterm infants. SUBJECTS AND METHODS: In this prospective cohort study, we monitored 54 prematurely born infants from birth to 24 months of age. Trained and calibrated dentists examined the oral cavity of these children to identify and categorize DDE. Information on perinatal variables was collected from the infants' medical records and interviews with their mothers. The data were analysed using Student's t test, a chi-squared test and Pearson's product-moment correlation coefficient. RESULTS: A total of 46.3% of the 54 children presented DDE, which was observed more frequently in the left hemiarch in children born extremely (<28 weeks of gestation) or very preterm (28 to <32 weeks; RR = 2.2; 95% CI 1.3-3.6), with very low birthweight (<1,500 g; RR = 2.0; 95% CI 1.1-3.5), who were admitted to the neonatal intensive care unit (RR = 1.3; 95% CI 1.0-1.7), and who were intubated (RR = 1.6; 95% CI 1.1-2.2). CONCLUSIONS: The high incidence of incisor enamel defects, particularly on the left side, was related to higher risk prematurity and to local trauma from intubation.

The impact of premature birth on the permanent tooth size of incisors and first molars.

BACKGROUND: Scientific evidence is insufficient to answer the question of whether premature birth causes altered tooth-crown dimensions. OBJECTIVE: To evaluate permanent tooth-crown dimensions in prematurely born children and to compare the findings with full-term born controls. SUBJECTS AND METHODS: Preterm children of 8-10 years of age were selected from the Swedish Medical Birth Register. One group consisted of 36 extremely preterm children (born before the 29th gestational week); the other group included 37 very preterm children (born during gestational weeks 29-32). The preterm children were compared with 41 matched full-term born children. Clinical examination and study casts were performed on all children. Permanent maxillary and mandibular first molars, central incisors, and laterals were measured with a digital sliding caliper on study casts. The tooth-crowns were measured both mesio-distal and bucco-lingual. RESULTS: Both the mesio-distal and bucco-lingual measurements in the maxillary and mandibular first molars had a significantly smaller width in the extremely preterm group compared with the full-term group. The central incisors and lower laterals were significantly smaller mesio-distally in the extremely preterm group compared to the full-term group. A reduction in tooth size of 4-9% was found between the extremely preterm group and the full-term group for both boys and girls. The maxillary first molars and mandibular left first molar were also smaller mesio-distally in the extremely preterm group compared to the very preterm group. The results indicate that the more preterm the birth, the smaller the tooth-crown dimensions. Independent of gestational age girls had generally smaller teeth than boys. CONCLUSION: Premature birth is associated with reduced tooth-crown dimensions of permanent incisors and first molars.

Premature birth--Studies on orthodontic treatment need, craniofacial morphology and function.

A series of studies have been initiated implying a unique opportunity to evaluate and compare malocclusion traits, orthodontic treatment need, craniofacial morphology, mandibular function, signs and symptoms of temporomandibular disorders (TMD) and headache between extremely preterm (EPT; born before the 29th week of gestation) and very preterm (VPT; born between 29 and 32 weeks of gestation) and full-term born children. THIS THESIS WAS BASED ON FOUR STUDIES: Paper I. A systematic literature review was undertaken to answer the following questions: Does prematurity result in alterations of palatal morphology, dental occlusion, tooth-crown dimensions, tooth maturation and eruption? What role does neonatal oral intubation play in the appearance of the alterations? Are the alterations in morphology permanent or transient? The literature search spanned from January 1966 to November 2002 and was later extended to September 2008. Furthermore, a quality analysis of the methodological soundness of the studies in the review was performed. Paper II-IV. The aims were to compare EPT and VPT 8- to 10-year-old children with matched full-term controls considering: Prevalence of malocclusion traits and orthodontic treatment need (Paper II). Craniofacial morphology (Paper III). Mandibular function, signs and symptoms of TMD and headache (Paper IV). KEY FINDINGS IN PAPER I AND THE SUPPLEMENTARY SEARCH: Moderate scientific evidence existed for more malocclusion traits among premature children. Limited evidence was found for no delay in dental eruption, if corrected age was considered for the premature children. Insufficientwas considered for the premature children. Insufficient evidence was found for altered tooth-crown dimensions and permanent alteration of palatal morphology among prematurely children. Thus, further well-designed controlled studies which should also consider orthodontic treatment need, craniofacial morphology, TMD and headache are needed. KEY FINDINGS IN PAPER II-IV: A higher prevalence of malocclusion traits and the assessed need of orthodontic treatment were higher among the preterm children compared with full-term born children (Paper II). Several craniofacial parameters differed significantly between preterm and full-term born children (Paper III). Preterm children did not differ from full-term born children when considering diagnoses according to the Research Diagnostic Criteria for TMD (RDC/TMD), signs and symptoms of TMD or headache (Paper IV). KEY CONCLUSIONS AND CLINICAL IMPLICATIONS: The increased survival rate of very preterm and especially the extremely preterm children contribute to a new group of children in society. The dental clinician should, therefore, be aware of the potential for a higher number of malocclusion traits, more malocclusion traits per individual, greater orthodontic treatment need and altered craniofacial morphology in prematurely born children compared with full-term born children. In spite of this, the prematurely born children had not more TMD or headache than full-term born children at the age of 8-10 years.

Craniofacial morphology in prematurely born children.

OBJECTIVE: To test the null hypothesis that there is no difference between the craniofacial morphology of prematurely born children and that of matched full-term born controls. MATERIALS AND METHODS: White children 8 to 10 years of age, born at the University Hospitals of Lund and Malmö and living in the same part of Sweden, were included. One group consisted of 36 very preterm children, born during gestational weeks 29 to 32; the other group included 36 extremely preterm children, who were born before the 29th gestational week. Subjects were compared with a control group of 31 full-term children, who were matched for gender, age, nationality, and living area. One lateral head radiograph was taken for each child, and the cephalometric analysis included 15 angular and 11 linear variables. Also, the height, weight, and head circumference of each child were registered. RESULTS: A significantly shorter anterior cranial base and a less convex skeletal profile were found among extremely preterm children, and significantly shorter maxillary length was noted in both extremely preterm and very preterm groups as compared with full-term children. The lower incisors were significantly more retroclined and retruded in the extremely preterm group compared with the very preterm group and the full-term control group. Extremely preterm children were significantly shorter, and both extremely preterm and very preterm children had significantly lower weight and smaller head circumference compared with full-term children. CONCLUSION: The null hypothesis was rejected because several craniofacial parameters differed significantly between preterm and full-term born control children.

Mandibular function, temporomandibular disorders, and headache in prematurely born children.

OBJECTIVE: To evaluate mandibular function, signs, and symptoms of temporomandibular disorders (TMDs) and headache in prematurely born 8- to 10-year-old children, and to compare the findings with matched full-term born controls. MATERIAL AND METHODS: Seventy-three preterm children were selected from the Medical Birth Register--one group comprising 36 extremely preterm children born before the 29th gestational week, the other group 37 very preterm children born during gestational weeks 29 to 32. The preterm children were compared with a control group of 41 full-term children matched for gender, age, nationality, and living area. The subjective symptoms of TMD and headache were registered using a questionnaire. Mandibular function, signs, and symptoms of TMD and headache were registered. TMD diagnoses were set per Research Diagnostic Criteria for temporomandibular disorders (RDC/TMD). RESULTS: No significant differences between groups or gender were found for TMD diagnoses according to RDC/TMD or for headache. The preterm children had smaller mandibular movement capacity than the full-term control group, but when adjusting for weight, height, and head circumference mostly all group differences disappeared. CONCLUSIONS: Prematurely born children of 8 to 10 years of age did not differ from full-term born children when considering diagnoses according to RDC/TMD, signs, and symptoms of TMD or headache.

Malocclusion traits and orthodontic treatment needs in prematurely born children.

OBJECTIVE: To evaluate if prematurely born children have higher prevalence of malocclusion traits and greater orthodontic treatment need than matched full-term born controls. MATERIALS AND METHODS: Seventy-three preterm children were selected from the Medical Birth Register and divided into two subgroups according to their gestational age. One group consisted of 37 very preterm children (VPT), born in gestational week 29-32, and the other of 36 extremely preterm children (EPT), born before the 29th gestational week. The subjects were compared with a control group of 41 full-term children, who were matched for sex, age, and nationality. Data from clinical examinations, study casts, and panoramic radiographs were used to determine malocclusion traits. The dental health component of the index of orthodontic treatment need (IOTN) was used to rank the treatment need. RESULTS: Two or more malocclusion traits occurred significantly more often among EPT (83.3%) and VPT children (73.0%), compared with the full-term children (51.2%). Significantly higher prevalence of deep bites and was found in EPT and VPT groups compared with the full-term control group. Deep bite was the most common malocclusion trait in the EPT and VPT group. Higher orthodontic treatment need was found for the preterm children but no differences in prevalence of malocclusion traits and treatment need were found between VPT and EPT children. CONCLUSION: The clinician should be aware of the potential for a higher number of malocclusion traits and greater orthodontic treatment need in prematurely born children compared with full-term children.

A systematic review of the consequences of premature birth on palatal morphology, dental occlusion, tooth-crown dimensions, and tooth maturity and eruption.

This systematic review addresses the question whether prematurity results in alteration of palatal morphology, dental occlusion, tooth-crown dimensions, and tooth maturation. A literature survey from the PubMed database covering the period from January 1966 to November 2002 used the Medical Subject Headings terms "infant, premature," and "infant, low birth weight" in combination with "jaws," "dental physiology," "dentition," and "tooth abnormalities." Controlled studies written in English and with definitions of premature birth according to the World Health Organization were selected. Two reviewers selected and extracted the data independently and also assessed the quality of the studies. The search strategy resulted in 113 articles, of which 13 met the inclusion criteria. Scientific evidence was found for altered palatal morphology in the short term among the premature children, and oral intubation was a contributing factor to the alterations. If corrected age was considered for the premature children, no delay in dental development and eruption was found compared with normally born children. Thus, the early birth of premature children must be taken in account when planning for orthodontic treatment. Because of the contradictory results and lack of longitudinal studies, the scientific evidence was too weak to answer the questions whether premature birth causes permanent alteration of palatal morphology, alteration of dental occlusion, and altered tooth-crown dimensions. To answer these questions and obtain reliable scientific evidence whether premature children are at risk for malocclusions from possible alterations of palatal morphology such as asymmetry and high arched palates, further well-designed controlled studies as well as longitudinal studies are needed.