TANAKA AND JOHNSTON'S MIXED DENTITION VALIDITY: AN ANALYSIS AMONG YEMENI ADULTS IN SANA'A CITY

Introduction and objective: Mixed dentition space analysis methods via Tanaka-Johnston analysis are regularly used all over the world. Conversely, the appropriate of this analysis between different ethnic groups is dubious. The study aimed to test the appropriate of the Tanaka-Johnston analysis for Yemeni adults and to arise regression equations designed for Yemen population if needed. Methods: The study included two hundred and twenty-seven (106 males and 121 females) Yemenis from Sana'a University, University of Science and Technology, and Al-Rehab Private Clinic. The mesiodistal widths of the four permanent lower canines, incisors, and premolars for the entire quadrants were determined with a digital caliper to the nearest 0.01 mm. To compare average presentation values ​​derived from this study with values ​​derived using Tanaka-Johnston equations, Student's paired t-test was used, as well as the chi-square (χ2) test used for appropriateness of fit. Result: Gender differences were observed in the total mesiodistal width of both canines and premolars in both arches as revealed by the t-test (p < 0.001). The sum of the actual mesiodistal width of the canines and premolars was compared with the expected widths derived from the Tanaka and Johnston equation and significant differences (p<0.001) were found. Regression analysis indicated that the sum of the mesiodistal width of the permanent mandibular incisors is a good predictor of that of un-erupted canines and premolars, with correlation coefficients ranging from 0.51 to 0.61. Accordingly, two linear regression equations were developed to predict tooth width for Yemeni males and females. Conclusion: It was concluded from this study that the Tanaka-Johnston analysis did not accurately predict the mesiodistal width of the unruptured canines and premolars of the Yemeni population. Moreover, new regression equations have been developed for the research sample that can be a standard for Yemen. However, further studies must be performed to verify the applicability and accuracy of these equations. Peer Review History: Received: 10 November 2021; Revised: 12 December; Accepted: 29 December, Available online: 15 January 2022 Academic Editor: Dr. Asia Selman Abdullah, Pharmacy institute, University of Basrah, Iraq, [email protected] UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file: Reviewer's Comments: Average Peer review marks at initial stage: 6.5/10 Average Peer review marks at publication stage: 7.5/10 Reviewers: Dr. A.A. Mgbahurike, University of Port Harcourt, Nigeria, [email protected] Rola Jadallah, Arab American University, Palestine, [email protected] Similar Articles: PREVALENCE AND CAUSES OF TRAUMATIC DENTAL INJURIES TO ANTERIOR TEETH AMONG PRIMARY SCHOOL CHILDREN IN SANA'A CITY, YEMEN OCCLUSAL CHARACTERISTICS OF THE PRIMARY DENTITION AMONG A SAMPLE OF YEMENI PRE-SCHOOL CHILDREN

Non-extraction orthodontic treatment in a patient with severe anterior crowding

A 12 years 6 months old Indian male presented with a chief complaint of irregular upper and lower front teeth. Patient exhibited a mild convex profile on Class l skeletal base with slightly decreased vertical proportions. This was complicated by severe upper and lower labial segment crowding. Also the molar relationship was half unit class ll bilaterally. Since the patient did not want to go for extraction of premolars, treatment involved use of Pendulum appliance along with upper and lower pre-adjusted edgewise appliance (0.022x0.028” slot) with MBT prescription. Various elastics and overlay wires were used along with proximal stripping for the correction of severe crowding in upper and lower anterior teeth.: Clinically Angle’s Class I occlusion was achieved bilaterally with good intercuspal relationship. Vertical growth continued throughout the treatment.

Three-dimensional Quantification of Enamel Preservation in Tooth Preparation for Porcelain Laminate Veneers: A Fully Digital Workflow In Vitro Study

SUMMARY Objective: This in vitro study aimed to evaluate the preservation of enamel after tooth preparation for porcelain laminate veneers (PLVs) at different preparation depths based on a fully digital workflow. Methods and Materials: Sixty extracted human maxillary anterior teeth, including 20 maxillary central incisors (MCIs), 20 maxillary lateral incisors (MLIs), and 20 maxillary canines (MCs) underwent microcomputed tomography (CT) scanning, and were reconstructed as three-dimensional (3D) enamel and dentin models. Subsequently, the three-dimensional (3D) enamel models were imported into Materialise, where each enamel model underwent seven types of virtual preparation for PLVs at preparation depths at 0.1-mm increments from 0.1-0.3-0.5 mm (D1) to 0.7-0.9-1.1 mm (D7). The enamel surface was depicted by merging the virtual preparation and, respective, dentin models. The enamel area and prepared surface were measured to calculate the percentage of enamel (R%). The data were statistically analyzed using one-way analysis of variance (ANOVA) (α=0.05). Results: The group-wise mean (standard deviation) R values for the MCIs were as follows: D1-D3: 100.00 (0) each, and D4-D7: 74.70 (2.45), 51.40 (5.12), 24.40 (3.06), and 0.00 (0), respectively. The group-wise mean R values for the MLIs were 100.00 (0), 73.70 (3.40), 53.50 (3.44), 25.20 (3.79), and 0.90 (0.99) for the D1-D5 groups, respectively; and 0.00 (0) each for the D6-D7 groups. The group-wise mean (standard deviations) R values for the MCs were as follows: D1-D3: 100.00 (0) each, and D4-D7: 99.00 (1.34), 77.10 (3.28), 74.20 (3.61), and 52.20 (4.09), respectively. The one-way ANOVA revealed significant differences between the seven groups in the MCIs, MLIs, and MCs (p&lt;0.05). Conclusions: Our results recommended preparation depths of up to 0.3-0.5-0.7 mm (MCIs), 0.1-0.3-0.5 mm (MLIs), and 0.4-0.6-0.8 mm (MCs) to facilitate complete intraenamel preparation. Moreover, 50% enamel was preserved at preparation depths of 0.5-0.7-0.9 mm (MCIs), 0.3-0.5-0.7 mm (MLIs), and 0.7-0.9-1.1 mm (MCs).

Assessment of the relationship between labial gingival thickness and the underlying bone thickness in maxillary anterior teeth by two digital techniques

This study aimed to noninvasively assess the relationship between the labial gingival thickness (GT) and the underlying bone thickness (BT) of maxillary anterior teeth by two digital techniques. A total of 30 periodontally healthy participants with 172 maxillary anterior teeth were enrolled. GT and BT were measured at 2, 4 and 6 mm apical to the cemento-enamel junction (CEJ) by two digital techniques: M1—cone-beam computed tomography (CBCT) and M2—digital intraoral scanning (DIS) combined with CBCT. The Pearson's correlation coefficient was calculated to determine the correlation between GT and BT. A significant negative correlation was identified between GT and BT at 2 mm apical to the CEJ for central incisors (CI), lateral incisors (LI), and canines (CA) both by M1 and M2, while a weak negative correlation at 4 mm apical to the CEJ was observed by M1 for CA. No significant correlation was found at other sites by both M1 and M2. The labial BT was < 1 mm in most cases (85% of CI; 97% of LI; and 90% of CA). Within the limitation of this study, it was concluded that GT and BT seemed to be negatively correlated at 2 mm apical to the CEJ. Therefore, caution is warranted when implant restoration at the esthetic area of the anterior teeth.

The influence of bracket torque on external apical root resorption in bimaxillary protrusion patients: a retrospective study

Background To evaluate the difference in root resorption between standard torque self-ligating brackets and high torque self-ligating brackets in bimaxillary protrusion patients after orthodontic treatment. Methods Pre-treatment and post-treatment Cone beam computed tomography (CBCT) of 32 patients (16 treated with the high torque DamonQ 0.022″ bracket and 16 with the 0.022″ standard torque self-ligating bracket) were selected. The first premolars were extracted from all patients before treatment. After mini-screw implants were inserted into the buccal region between the second premolar and first molar, 150 g of force was applied to retract the upper and lower anterior teeth to close the extraction space on each side. CBCT images of all patients were taken before and after treatment. Three-dimensional reconstruction of the maxillary central incisor, lateral incisor and canine was conducted with Mimics 20.0 software. The volumes of the roots were calculated using Gomagics Studio 12.0 software. The differences between the pre-treatment and post-treatment root volumes were statistically evaluated with a paired-samples t-test. Results There was no statistically significant difference in root resorption degree between the two kinds of torque brackets. The patient’s degree of root resorption in the high torque self-ligating group was greater than that in the standard torque group. Conclusions There was no significant difference in root external apical resorption between the high torque self-ligating brackets and the standard torque self-ligating brackets in bimaxillary protrusion patients.

Bracket Failure in Orthodontic Patients: The Incidence and the Influence of Different Factors

Failure of brackets is a common problem in orthodontics. This affects the treatment time, cost, and compliance of the patient. This study was conducted to estimate the bracket failure rate and the related factors for the long term. Methodology. This ambidirectional cohort study included 150 nonsyndromic orthodontic patients undergoing fixed appliance therapy for the last two years. The same patients were followed for 7 months. Different variables related to bracket failure were evaluated. The available data were analyzed descriptively, and the Kaplan-Meier estimate was used to measure the bracket survival rate from the date of bonding to failure. Results. A total of 180 bracket bond failures in the 150 included patients (52.2% males and 47.8% females) with a median age of 17 years (range 10-25 years). 69% of brackets failures were reported within the first 6 months after bonding. About 58.3% of bracket failure was noticed in adolescent patients before the age of 18 years. The majority of the cohort (81.1%) has good oral hygiene. The failure rate in patients with normal overbite was 41.1%, in decreased overbite cases was 15%, while in deep bite cases the failure rate was 43.9% with a statistically significant difference. Adults show less bracket failure (41.7%) than adolescent patients (58.3%). More bracket failure was noted in the lower arch (55%) than the upper arch (45%), and there were more bond failures posteriorly (61%) than on the anterior teeth (39%). Majority (41.1%) of the bracket failed on round NiTi wires. Conclusion. The bracket failure rate was 6.4%, with most bracket failure occurring in the first 6 months after bonding with individual difference. There was more incidence of bond failure in an increased overbite, adolescents, lower arch, posterior teeth, and lighter alignment wires.

Intrusion of the maxillary posterior teeth with a single buccal mini-implant positioned bilaterally in young adults with a tendency towards hyperdivergence: A clinical study

Background: Skeletal anchorage systems have been used for intrusion of the posterior teeth with satisfactory results. To achieve this, mini-implants are placed at anatomically challenging sites such as the palate or require several mini-implants to produce the desired effect. Objective: To determine the magnitude of intrusion of the maxillary posterior teeth achieved on a continuous arch wire using a single buccal mini-implant placed bilaterally in young patients with a tendency towards hyperdivergence and to evaluate its influence on the skeletal, dental and soft-tissue structures. Methods: A total of 17 patients with proclination of the anterior teeth, tendency towards hyperdivergence and clockwise rotation of the mandible were selected. First premolars were extracted as part of treatment protocol. A 0.022-MBT bracket prescription was used. Mini-implants were placed bilaterally on the buccal aspect at the mucogingival junction or slightly gingival to it between the maxillary second premolar and first permanent molar. A total of 200 g of intrusive force was placed from a continuous 0.019 × 0.025 inch stainless-steel arch wire to the mini-implant by means of an elastomeric thread on both sides. Lateral cephalograms and study models were taken before the start of intrusion and six months later. Parametric and non-parametric tests were done to assess treatment results. Results: Significant intrusion was observed in the maxillary molar and premolar region with tendency towards intrusion in the anterior region. There was significant decrease in lower anterior facial height (LAFH) with anti-clockwise mandibular rotation, decrease in facial proportion index and total facial height. No changes were observed in the transverse plane. Conclusion: Intrusion of the permanent maxillary molar can be achieved on a continuous arch wire with a single buccal mini-implant placed bilaterally with improvement in facial aesthetics, especially in the vertical plane. This method may be beneficial in patients with borderline vertical discrepancy treated with conventional friction mechanics during space closure after first premolar extractions.

Oral health–related quality of life (OHRQOL) of preschool children’s anterior teeth restored with zirconia crowns versus resin-bonded composite strip crowns: a 12-month prospective clinical trial

Objectives To compare oral health–related quality of Life (OHRQOL) of preschool children’s anterior teeth restored with prefabricated zirconia crowns (ZC) versus resin-bonded composite strip crown (RCSC). Materials and methods A prospective clinical trial included 136 children with early childhood caries aged 36–71 months who were assigned into prefabricated ZC and RCSC groups. A total of 344 teeth were restored either with 170 ZCs (49.4%) and 174 RCSCs (50.6%). Wilson and Cleary’s conceptual model was to associate the study predictors to the OHRQOL. Early Childhood Oral Health Impact Scale (ECOHIS) was used to assess the OHRQOL at 6 and 12 months. Mann–Whitney U test was used in comparing OHRQOL mean scores in the two groups and Wilcoxon signed-rank test with the effect size (r) to measure the intragroup OHRQOL change. A Poisson regression model was used to study potential risk factors associated with the overall OHRQOL. Results After 12 months, the USPHS parameters of the ZC were significantly superior compared to the RCSC. Overall ECOHIS mean scores in the ZC group were significantly lower than that of the RCSC group at T1 and T2 (p < 0.001). Remarkable enhancement of the OHRQOL at the follow-ups with a large effect size (r < 0.8) was observed. Restoration type, retention, baseline OHRQOL, and color had a significant impact on the overall OHRQOL at 12 months. Conclusions Preschool children OHRQOL treated with ZC were significantly better than those who received RCSC. Clinical relevance One of the optimum treatment standards in pediatric dentistry is the esthetic demand which has significance on the child’s OHRQOL and subsequently child’s general health quality of life. It is beneficial to the dentist to identify the influence of esthetic restorations on the OHRQOL of preschool children which aids in future decision-making. The longitudinal nature of the study enables the dentist to identify the changes of children’s OHRQOL.

Microapical surgery management of root resorption in anterior teeth caused by dental trauma: case report

Root resorption (RR) is a common complication of traumatic dental injuries (TDIs), which could result in tooth loss and affect life in severe cases. The management of a traumatized tooth with RR remains a challenge for clinicians. In our presented cases, the impacted teeth had a history of trauma and underwent thorough non-surgical endodontic treatment; however, RR still occurred months later and could be observed through a periapical radiograph. Therefore, root canal therapy was performed under a dental microscope with a quick-setting calcium silicate cement to repair the RR site. After a long follow-up, the affected teeth showed almost complete healing of the periradicular tissues without sign of RR. This report demonstrates that external root absorption is typically a consequence of traumatized teeth. However, to date, there is still no effective method for its treatment. Here, we successfully applied microscopical surgery to the traumatized teeth experiencing root absorption and provided them with a new healing opportunity.