Effect of wire diameter and extent of wire composite splint on the mobility of luxated and anchor primary teeth: A typodont study.

BACKGROUND/AIMS: The recommendations for splinting are well established for the injuries of permanent dentition; however, ambiguity still exists for the injuries in primary dentition. Hence, this study aimed to determine the most appropriate dimensions of stainless steel wire and its extent, for achieving the physiologic mobility in primary dentition. MATERIAL AND METHODS: This study was designed as an in vitro experiment by using a typodont model of primary dentition. The baseline mobility of primary maxillary incisors was calibrated to the physiologic mobility of natural primary incisors by using a Teflon tape wrapped around the roots of resin teeth. Splinting was done using a stainless steel wire of 0.2 mm (Group I), 0.3 mm (Group II), and 0.4 mm (Group III). These groups were subdivided (a, b, and c) on the basis of the extent of the splint, and pre splint mobility (Pre-PV) and post-splint mobility (Post-PV) were tested by Periotest M. The splint effect was calculated by subtracting Post-PVs and Pre-PVs. RESULTS: The normal values of mobility in healthy human volunteers ranged from 10.5 to 13. The overall splint effect was higher in Group III irrespective of the extent of the splint, whereas it was found to be the lowest in Group I (b and c). The splint effect increased with the extent of the splint in all the groups. Among all the groups, the splint effect on the anchor teeth was observed to increase with the extent of the splint and the diameter of the wire. CONCLUSION: The mobility of the injured and anchor teeth splinted with 0.2-mm stainless steel wire was similar to the pre-splint and physiologic mobility. The most favorable extension was one tooth adjacent to the injured tooth on each side for both 0.2- and 0.3-mm wires.

Traumatic dental injuries in the primary dentition - a review.

Traumatic oral injuries in children involve trauma to the dentition and the surrounding oral soft tissue structures. They usually present as an emergency hence their management poses a challenge globally. Treatment of a tooth fracture, displacement or loss is determined by the type and severity of the injury independent of the etiology. It necessitates the experience for behavior management in a child, ascertaining a patient centered diagnosis, formulating a definitive treatment plan, explanation and consent of oral care to the parents or carer with optimal operator skills. This article provides an overview on the types of oral injury in a child patient, their recognition, diagnosis and management based on credible, practical and readily understandable evidence.

Trauma in primary teeth and its effect on the development of permanent successors: a controlled study.

Objective: This controlled study investigated the occurrence of sequelae to permanent successors (SPS) following traumatic dental injury in primary teeth (TDIp). Additionally, this study evaluated whether TDIp is a risk factor for SPS, with a focus on an association between SPS and the child's age and type of trauma. Materials and methods: The trauma group (TG) consisted of permanent teeth, whose antecessors had suffered TDIp, in a population of children with complete eruption of permanent teeth. The control group (CG) consisted of permanent teeth from the same individuals, whose antecessors had not suffered TDIp. There were 214 cases of TDIp with their respective permanent teeth. In the CG 247 permanent teeth, whose antecessor had not suffered TDIp, were included. Data concerning such teeth and when TDIp occurred (in terms of the child's age) and types of SPS were collected. The chi-square test, regression logistic with generalized estimating equations (GEE) test, and risk analyses were applied to investigate the associations. Results: Overall, 29% of the permanent teeth in the TG presented SPS. This was compared to the development disturbances in the CG, which was 7%. The TG demonstrated the highest risk for SPS (OR, 5.388; p = .0001). The discolouration of enamel (37%) was the most common type of SPS found. SPS was more prone to occur in permanent teeth whose antecessors had been intruded (39%; p < .001). TDIp when the child was 1-year old was associated with SPS (p < .001). Moreover, children who had TDIp had a 4.1 times higher risk of presenting SPS. Conclusions: TDIp is a risk factor for the development of SPS. All types of TDIp caused SPS in this research. Additionally, the younger ages at the time of the injury and intrusions were related to SPS.

Dental trauma on primary teeth at different root resorption stages-A dynamic finite element impact analysis of the effect on the permanent tooth germ.

BACKGROUND/AIM: Dental trauma is a common emergency in children with primary teeth. The aim of this study was to determine stress propagation to the permanent tooth germ and surrounding bone and soft tissues during dental trauma to primary central incisors with three levels of physiological root resorption. MATERIAL AND METHODS: Stresses were determined using finite element analysis (FEA). Cross-sectional models were created using cone-beam computed tomography images of 3.5, 5, and 6 years olds, representing three different physiological root resorption stages of a maxillary primary central incisor. The models included periodontal ligament, bone, and soft tissues. An impact with an asphalt block moving at 1 m/s,was simulated for two impact two directions, frontal on the labial tooth surface, and on the incisal edge. Stresses and strains were recorded during impact. RESULTS: The impact caused stress concentrations in the surrounding bone and soft tissues and permanent tooth germ, regardless of the direction of impact and the primary tooth resorption stage. Impact stresses in dental follicles and surrounding bone increased in models with more physiological root resorption of the primary tooth. Incisal impact generated higher stress concentrations in surrounding bone and soft tissues and permanent tooth germ regardless of physiological root resorption stage. The primary incisor with no physiological root resorption showed high stress concentrations at its root apex. CONCLUSION: During impact to a primary incisor, stresses most significant for potential damage to the formation of permanent enamel and dentin were at the dental follicle and surrounding bone tissue with the three levels of physiological root resorption.

Unusual sequelae of a subluxated primary incisor on its permanent successor tooth.

Traumatic dental injuries (TDIs) such as subluxations of primary teeth can have significant consequences on their developing successors. The purpose of this report is to present a 3-year-old boy who encountered subluxation injuries to his primary incisors which subsequently had an unusual consequence on the permanent successor. On the day of the TDI, based on clinical and radiographic examinations, a diagnosis of subluxation of teeth 52, 51 and 61 was made. By age 5, the patient reported that tooth 51 had exfoliated, and consequently, tooth 11 had erupted into the oral cavity, but it was very loose. Eventually, the patient lost the crown of tooth 11 during his routine daily activities. Furthermore, radiographic examination at age 11 revealed a small root-like structure in the tooth 11 region. It is very unusual to have premature loss of a permanent incisor following subluxation to its predecessor. Therefore, the present case serves as a good example to emphasize that even minor TDIs are of considerable importance as they may lead to unexpected consequences.

How does orofacial trauma in children affect the developing dentition? Long-term treatment and associated complications.

Each year, millions of children are injured and live with the consequences of those injuries. Through infancy and childhood, orofacial trauma caused by falls or being struck by or against objects occurs in children. The long-term implications on the developing permanent teeth are little known, even when the oral region is the second most frequently injured body area in children under 6 years of age. During this period, the developing permanent teeth may be directly involved after trauma, causing mild to severe hypoplasia, displacement, damage to the tooth germ, or an extended range of morphofunctional disturbances. In some cases, the effects of oral and dental injuries caused by trauma appear later with the eruption of the permanent incisors when ectopic eruption, malalignments, and other developmental disturbances become visible. Therefore, long-term follow up of the patient in order to diagnose and treat associated complications becomes essential. Critical points for facing the consequences of orofacial trauma on the developing dentition are to recognize the impact of orofacial trauma in young children and the dentist's role in providing anticipatory guidance to parents and health care professionals, differentiate between mild and severe disturbances affecting the developing permanent teeth after oral injuries in early childhood, recognize the importance of follow-up controls, and recognize the importance of early referral to a pediatric dentist and orthodontist for diagnosis and treatment planning.

A retrospective study of traumatic dental injuries in primary dentition: treatment outcomes of splinting.

OBJECTIVE: Splinting in primary dentition is limited to several traumatic dental injuries. The prognosis associated with splint use has not been fully investigated. In this study, we investigated the outcomes of traumatic injuries in primary teeth treated with splinting. MATERIALS AND METHODS: We retrospectively analysed 137 children with root fractures and lateral and extrusive luxation injuries to their primary teeth who were treated with semi-rigid splints between 2010 and 2016. Treatment outcomes were analysed in patients with follow-up periods of >6 months. The outcomes of splinting were based on clinical and radiographic evaluations performed during follow-up examinations. RESULTS: In total, 182 primary teeth were examined, and of these, 90 teeth were treated using semi-rigid splints. In the splint group, pathological root resorption (31.1%) was the most common complication, whereas pathological tooth loss (25.0%) was found most common in the observation group. Splinting in root fractures showed a good prognosis, whereas in lateral and extrusive luxations, it did not (p < .05). There were no relationship between treatment delay and prognosis (p > .05). CONCLUSIONS: Depending on the type of luxation, splint therapy results in acceptable outcomes and may be a feasible treatment option.

Profile of intrusive luxation and healing complications in deciduous and permanent teeth - a retrospective study.

OBJECTIVE: This retrospective study analyse the profile of intrusion in deciduous (DT) and permanent teeth (PT), the occurrence of healing complications (HC), type of treatments and predisposing factors. METHODS: The records of patients attended from 2005 to 2011 were analysed. Records of patients who had one or more intruded DT or PT were included in the study. Data collected from dental records included age, gender, attendance (immediate/mediate), healing complications and type of treatment. A Chi-square test and Logistic regression (p ≤ .05) were performed to evaluate the associations between the type of teeth and presence of HC, as well as to explore the interactions between predisposing factors. RESULTS: The intrusion prevalence was 9.98% in DT and 2.45% in PT. Partial intrusion (57.3%) with palatal direction of the crown (61.8%) was most prevalent in DT, while complete intrusion (56.7%) with buccal direction of the crown (58.1%) was predominant for PT. Mobility was the most common HC in DT compared to root resorption in PT. Minimally invasive treatments were the most common therapy for DT compared to invasive treatments for PT. PT demonstrated increased HC when compared to DT (p = .004). A logistic regression illustrated that the level of intrusion and crown direction during the trauma did not influence the occurrence of HC (p > .05). CONCLUSION: Intrusion's profile in DT and PT are different. PT showed more HC than DT, however the level of intrusion and crown direction were not associated with the presence of HC.

Frequency of crown and root dilaceration of permanent incisors after dental trauma to their predecessor teeth.

BACKGROUND/AIMS: Dental trauma to the predecessor teeth can cause crown and root dilacerations to the successor teeth, which can interfere with the normal development of permanent teeth. The aims of this study were to verify the types of trauma more frequent to the predecessor teeth that cause dilaceration to their successor teeth, to determine the frequency of crown and root dilacerations in permanent incisors, taking into account the child's age at the time of trauma, and to describe the types of treatment performed. MATERIALS AND METHODS: Details of 815 anterior primary teeth with dental injury were obtained from 483 dental records of children aged 0-9 years at the time of trauma. RESULTS: Of 815 traumatized primary teeth, 161 successor teeth were clinically and radiographically reviewed until complete eruption and had some type of sequel. Avulsion and intrusive luxation were the most frequent types of trauma to the predecessor teeth that caused dilaceration to their successor teeth. Enamel discoloration (30.4%), hypoplasia (23.6%), root (14.3%) and crown (9.9%) dilacerations were the most common sequelae observed in the successor teeth. Root and crown dilacerations were more frequent in children aged more than and up to 3 years, respectively. Tooth extraction and orthodontic treatment were the most common treatments. CONCLUSIONS: Dentists must be aware of the relationship between the child's age at the time of trauma to the predecessor tooth and the type of sequel to the successor tooth in order to diagnose, monitor, and treat the sequel properly.

Diagnostic ability of a smart phone app (injured tooth) in diagnosing traumatic injuries to the teeth - a multicentre analysis.

BACKGROUND: Dental trauma is not uncommon. The initial management provided at the time of injury is critical in predicting prognosis. However, initial management depends on correct diagnosis. Recently an App named 'Injured Tooth' was made available to diagnose traumatic injuries to the teeth and supporting structures. AIM: To test the diagnostic ability of the Injured Tooth App compared with the conventional method of diagnosing traumatic injuries to the teeth. DESIGN: A cross-sectional study was conducted at three different centres with 176 patients aged 0-15 years, having 201 injured teeth. Diagnosis of the injured teeth in these children at every centre was done independently by one experienced faculty using the traditional method and by a student using the Injured Tooth App. RESULTS: Injured Tooth App gave a correct diagnosis for 197 teeth included in the study. Statistical analysis showed that there was good agreement (Kappa = 0.973) between the diagnosis given by the App and the experienced faculty. CONCLUSIONS: The study found that the diagnosis given by the Injured Tooth App was in good agreement with the diagnosis given by an experienced faculty. Hence, the App can be successfully used by dental students to arrive at diagnosis.

Dental trauma and bicycle safety: a report in Italian children and adolescents.

OBJECTIVES: This retrospective study aims to analyze the pattern of oro-facial trauma from bicycle accidents in Italian children and adolescents, focusing on the safety devices used. METHODS: The medical records of 1405 patients of the Dental Clinic of the University of Brescia, between the age of 0 to 18, who experienced a dento-facial trauma from the use of a bicycle, were analyzed. Data regarding age, gender, weight, height, dominant hand, type of bicycle, use of safety devices, location and type of dental trauma, teeth involved, bone fractures and soft tissue lesions were recorded. Statistical analysis was performed. RESULTS: The majority of the traumatic events occurred in children within the 8-10 years of age-range; 1085 teeth were injured, of which 975 permanent teeth (89.9%) and 110 primary teeth (10.1%). The most common dental lesions were the coronal fractures (complicated and not complicated) while the most frequently involved teeth were the upper central incisors; 11% of patients were also treated for maxillo-facial fractures. A protective helmet was worn only in 3% of the cases; not one patient wore a mouth-guard. The use of helmets was more frequent in children and adolescents riding racing-bikes competitively, compared to those who were mountain bikers (p < 0.05). CONCLUSIONS: Bicycle accidents can have serious oro-facial consequences. Therefore, national and regional efforts should be made in Italy to promote head and mouth protection in cycling.

The risk of healing complications in primary teeth with concussion or subluxation injury-A retrospective cohort study.

BACKGROUND/AIM: Traumatic dental injuries in the primary dentition occur frequently. Long-term complications may potentially cause damage to the permanent successor. The aim of this study was to report the risk of pulp necrosis (PN), pulp canal obliteration (PCO), repair-related resorption (RRR), infection-related resorption (IRR), ankylosis-related resorption (ARR), and premature tooth loss (PTL) in primary teeth following concussion and subluxation injuries, and to identify possible risk factors for PN, PCO, and PTL following subluxation. MATERIAL AND METHODS: The study was a retrospective analysis of a cohort comprising 31 patients (36 teeth) with concussion injury and 174 patients (241 teeth) with subluxation injury. No treatment was performed. The follow-up program included examination after 4 weeks, 8 weeks, 6 months, 1 year, and when the patients were 6 years of age. Minimum follow up was 1 year or until the time of tooth loss. STATISTICS: Kaplan-Meier and Aalen-Johansen methods and Cox regression analysis. Level of significance was set at 5%. RESULTS: Risk estimated after one year. Concussion: PCO 8.6% (95% CI: 0-17.9), PN 5.7% (95% CI: 0-13.4), PTL 5.6% (95% CI: 0-13.4). Subluxation: PCO 23.2% (95% CI: 17.8-28.6), PN 8.3% (95% CI: 4.8-11.8), IRR 2.6% (95% CI: 0.5-4.6), PTL 9.5% (95% CI: 5.0-14.1). Most complications (95%) were diagnosed within the first year. Most cases of PN (65%) and PTL (85%) were seen in patients aged 4 years or more. CONCLUSION: Primary teeth with concussion or subluxation injury carry a low risk of PN and infection with periapical inflammation, root resorption, and PTL. Nearly all complications were diagnosed within the first year after the injury. The risk of PTL was highest in patients more than 4 years of age at the time of injury.

The risk of healing complications in primary teeth with intrusive luxation: A retrospective cohort study.

BACKGROUND/AIMS: Intrusive luxation is a frequent injury in the primary dentition. Complications such as ankylosis or pulp necrosis (PN) and infection with periapical inflammation may affect the developing permanent tooth if not diagnosed and treated in time. The aim of this study was to report the risk of PN, pulp canal obliteration (PCO), infection-related resorption (IRR), ankylosis-related resorption (ARR) and premature tooth loss (PTL) in primary teeth following intrusive luxation, and to identify possible risk factors for PN and PTL. MATERIALS AND METHOD: A retrospective analysis of a cohort comprising 149 patients 194 intruded primary incisors. No treatment was performed. The follow-up programme included examination after 4 weeks, 8 weeks, 6 months, 1 year, and at 6 years of age. The minimum follow-up period was 1 year or until time of tooth loss. STATISTICS: The Kaplan-Meier and Aalen-Johansen methods were employed along with Cox regression analysis. The level of significance was 5%. RESULTS: Risks estimated after 3 years: PCO 38.9% (95% CI: 31.8-46.0), PN 24.2% (95% CI: 17.7-30.6), IRR 8.8% (95% CI: 4.5-13.1), ARR 3.6% (95% CI: 1.0-6.2) and PTL 39.4% (95% CI: 31.2-47.5). Most teeth (83.7%) spontaneously re-erupted within the first year. Most complications were diagnosed within the first year. The risk of PN was lowest in patients less than 2 years of age. The degree of intrusion or a concomitant crown fracture did not affect the risk of PN or PTL. CONCLUSIONS: Over 80% of the intruded primary teeth re-erupted spontaneously. However, nearly one-third of the teeth showed complications such as pulp infection/periapical inflammation or ankylosis, which could potentially affect the development of the permanent incisor. Therefore, patients should be monitored regularly, especially during the first year after injury, to diagnose and treat complications in time.

Osseo-gingival pathology as sequelae of dental trauma to the primary upper incisor: a case series.

BACKGROUND: Osseo-gingival pathology (OGP) may be observed in traumatized primary teeth, and its knowledge is essential for treatment decision. AIM: To describe the occurrence and treatment of OGP in traumatized primary upper incisors. DESIGN: One examiner collected data from patients' charts of the Clinic of Trauma in Primary Teeth of the University of Sao Paulo. OGP was divided into apical fenestration (AF), total gingival recession (TGR), and partial gingival recession (PGR). RESULTS: From 2516 charts, 61 patients (2.4%) presented 73 teeth with OGP (9.6% AF, 19.2% TGR and 71.2% PGR). OGP was observed in 63% of male and 43.8% of children aged 4-5 years old. Mean time between trauma and diagnosis was 15 months AF, 23.5 months TGR, and 7.5 months PGR. Periodontal trauma occurred in 86.3% of teeth with OGP. Pulp necrosis was observed in all cases of AF and 92.9% of TGR; however, 76.9% of PGR were vital. All teeth with AF and 85.7% of TGR were extracted, and 44.2% of PGR were monitored. CONCLUSIONS: Osseo-gingival pathology has low occurrence in traumatized primary upper incisors. The treatment for AF and TGR is tooth extraction, and for PGR is tooth monitoring or extraction depending on the case severity.

Rare sequelae in the permanent successor due to trauma in the primary incisor: a case report.

Severe dental trauma-such as intrusion or avulsion-to the primary dentition in infants and toddlers may cause developmental disturbances in the permanent successor. In this case, a 9-year-old boy was referred for treatment due to the absence of his permanent maxillary right central incisor. The mother reported avulsion of the corresponding primary tooth when the patient was 2 years old. The radiographic examination revealed impaction and root dilaceration of the permanent tooth; therefore, the treatment plan was tooth extraction. The extracted tooth presented multiple abnormalities, including enamel discoloration, enamel hypoplasia, root dilaceration, and root duplication. Several factors need to be considered when treatment of traumatic sequelae to a permanent successor is planned, including the age of the patient, the developmental stage of the permanent successor at the time of trauma, and the type of trauma to the primary tooth.

Dental Anomalies in Permanent Teeth after Trauma in Primary Dentition.

OBJECTIVE: This retrospective study aims to evaluate the prevalence of dental anomalies in permanent teeth as a result of a trauma concerning the predecessor primary teeth. STUDY DESIGN: A total of 241 records of children (118 males and 123 females, mean age 3.62 ± 1.40) affected by trauma on primary teeth were analyzed. All patients were recalled to evaluate the status of the permanent successor teeth by clinical and radiographic investigations. RESULTS: Out of 241 patients, 106 patients (for a total of 179 traumatized primary teeth) presented at the recall. Dental anomalies on successor permanent teeth were detected in 21 patients (19.8%), for a total of 26 teeth (14.5%) and 28 anomalies. Anomalies of the eruptive process were the most observed disturbances (60.7%), followed by enamel hypoplasia (25%) and white spots (14.3%). A higher percentage of anomalies on permanent teeth was observed when trauma occurred at an age less than 36 months (38.5% of cases). Intrusive and extrusive luxation were related with the most cases of clinical disturbances in the successor permanent teeth. CONCLUSIONS: The results of this study highlight the risk of dental anomalies after a trauma in primary dentition, especially in early-aged children and in case of intrusive luxation.

Pulp Calcification in Traumatized Primary Teeth - Classification, Clinical And Radiographic Aspects.

OBJECTIVE: The aim of this study was to standardize the nomenclature of pulp alteration to pulp calcification (PC) and to classify it according to type, quantity and location, as well as relate it to clinical and radiographic features. STUDY DESIGN: The dental records of 946 patients from the Research and Clinical Center for Dental Trauma in Primary Teeth were studied. Two hundred and fifty PC-traumatized upper deciduous incisors were detected. RESULTS: According to radiographic analysis of the records, 62.5% showed diffuse calcification, 36.3% tube-like calcification, and 1.2% concentric calcification. According to the extension of pulp calcification, the records showed: 80% partial calcification, 17.2% total coronal calcification and partial radicular calcification, and 2.8 % total coronal and radicular calcification. As for location, only 2.4% were on the coronal pulp, 5.2% on the radicular pulp and 92.4% on both radicular and coronal pulp. Regarding coronal discoloration, 54% were yellow and 2% gray. In relation to periradicular changes, 10% showed widened periodontal ligament space, 3.1% internal resorption, 10% external resorption, 10.4% periapical bone rarefaction. CONCLUSIONS: Since PC is a general term, it is important to classify it and correlate it to clinical and radiographic changes, in order to establish the correct diagnosis, treatment and prognosis of each case.

Alveolar Fracture Caused by Tooth Extraction at Home.

Injuries to the teeth and surrounding structures are relatively common. Although traumatic injuries caused by falls or activities related to sports are widely discussed, the same cannot be said regarding accidents arising from non-professional extraction of primary teeth. The present study reports a 6-year-old male child who underwent mandibular alveolar bone fracture during non-professional extraction of his central lower left incisor at home, performed by his 30-year-old aunt. The root of the tooth was with an irregular physiological resorption, which acted as a lever component for the mechanical force applied, leading to bone fracture. Although not common, the possibility that dental roots with irregular resorption can act as a possible risk factor for accidents if the parents or guardians of children during the period of transitional dentition try to perform intentional extraction of primary teeth should be highlighted. Parents should always consult a professional, preferably a pediatric dentist, for monitoring this period of transitional dentition.

Cone-Beam Computed Tomography Study Of Crown Dilaceration With a Talon Cusp in an Unerupted Permanent Maxillary Tooth.

This article describes a rare case of crown dilaceration with a talon cusp in an unerupted permanent maxillary central incisor. Our patient was a 7-year-old boy with a history of trauma to his primary maxillary teeth (#51 and 52), at 3 years of age complaining of failure of eruption of tooth #11. Periapical radiography showed incomplete formation of tooth root #11 and more superior position of tooth bud #11 relative to tooth bud #12. A cone-beam computed tomography was ordered, which revealed crown dilaceration with a talon cusp in tooth bud #11. The patient was scheduled for follow-up at 6 months.

The post-traumatic colour change of primary incisors: a colourimetric and longitudinal study.

BACKGROUND: Tooth colour change after trauma has been described subjectively as ranging from yellow/pink to grey/black. AIM: To investigate the longitudinal colourimetric change of post-traumatic discoloured primary incisor using an intraoral colourimeter. DESIGN: A total of 34 primary incisors from 15 boys and eight girls were studied. The mean post-injury day during clinic visits (SD) and number of visit was 205.4 (194.8) and 3.9 (2.0). CIE L* (lightness), a* (green-red) and b* (blue-yellow) of the maxillary primary incisors were measured at every visit. The colour difference (ΔE*ab ) was calculated between the traumatized tooth and the control. Scatter graphs were made depicting the colour change of discoloured teeth and the ΔE*ab over time. RESULTS: Mean CIE L*, a* and b* of the unaffected control were 80.8 (2.29), 0.9 (0.77) and 13.1 (2.67), respectively. L* gradually decreased to 70.7 (on day 71), then slowly recovered. a* increased to 3.7 (day 29) and decreased slowly. b* only demonstrated a small change that was within the control range during the follow-up. ΔE*ab increased to 9.58 (day 56) and decreased slowly. CONCLUSION: The earlier recovery of a* was followed by the recovery of L*. During the post-traumatic period, ΔE*ab failed to reach the clinically acceptable threshold.