Various methods of canine retraction in premolar extraction space: A case series

Following article is the review and presentation of various methodologies of canine retraction [e.g.– methods under sliding and friction less mechanics, facilitation with TADs (Temporary Anchorage Devices) and MOPs (Micro-Osteo-Perforations), and invasive procedures etc.] and comparison of these methods in terms of rate of canine retraction, and molar anchorage loss. Patient’s age ranges between 15y to 19y and only right maxillary canine was taken for comparison purpose.

A Cephalometric Evaluation of Soft Tissue Following Maxillary Incisors Retraction

Background: Class 2 Division 1 is the most prevalent type of malocclusion affecting about 32% of Pakistani population. With upper maxillary premolar extraction is one of most frequent treatment choice. Aim: To evaluate the effects of these extractions on soft tissue show variable results depending upon the sex, ethnicity, maxillary arch crowding and pretreatment structure of lips. Methods: In this study pretreatment cephalograms of 106 Class 2 div 1 patients were taken whose treatment plan include extraction of maxillary 1st premolar. Then the second and final cephalograms were taken when retraction of incisors was completed. Mean changes in the position of upper and lower lip were measured with respect to Ricketts E-line before and after completion of retraction of maxillary incisors. Results: After the extraction of premolars there is a significant (P value=0.000) reduction in the lip protrusion of -2.033mm±1.148mm and -1.695mm±1.628mm in both upper and lower lip respectively. Conclusion: Extraction of maxillary premolars cause significant reduction of lip prominence and achieve facial esthetic balance. Keywords: Class 2 div 1, lip position, Premolar Extraction

Comparison of radiographic changes in the alveolar crest after extraction of fully and partially erupted premolars during orthodontic treatment: A retrospective analytical study

Background. The alveolar process plays an essential role in providing dental support and gradually disappears with tooth loss. Space deficiency can cause one premolar to remain semi-erupted adjacent to a fully-erupted premolar. During orthodontic treatment, each of these premolars can be extracted. This retrospective study aimed to compare radiographic changes of the alveolar crest due to orthodontic movements of fully-erupted and semi-erupted premolars into the extraction sites before and after treatment. Methods. The patients were divided into the fully-erupted premolar extraction (first) group and the semi-erupted premolar extraction (second) group. The distance between the cementoenamel junction (CEJ) and the alveolar crest, from the distal aspect of the canine to the mesial aspect of the first molar, was measured on panoramic radiographs of 78 patients (39 from each group) before and after treatment with a digital caliper. Changes in the alveolar crest were compared between the two groups. Finally, the height differences of the alveolar crest in mesial and distal aspects of the remaining premolars in both groups were calculated at the end of treatment. Descriptive statistical analyses and paired and independent t tests were used in the study. Results. The distance from the CEJ to the alveolar crest at mesial and distal aspects in the first group and the distal aspect of the extraction site in the second group increased significantly. However, changes at the mesial aspect were not significant in the second group. Comparing the alveolar crest height between the two groups and between the mesial and distal aspects of the remaining premolar tooth indicated no significant differences. Conclusion. No significant difference was observed between the extraction of a fully-erupted or semi-erupted premolar to obtain greater alveolar height.

Combination of forsus fatigue resistant device and premolar extraction for the management of a skeletal class II malocclusion

Treatment of class II malocclusion requires accurate diagnosis and treatment planning. This case report outlines the successful management of a growing skeletal class II using Forsus fatigue resistant device for correction of skeletal parameters and premolar extractions for correction of dental parameters. The patient’s profile improved significantly with a 4° reduction in ANB angle. An ideal overjet, overbite and molar relation were also attained.

Articaine VS Lignocaine in Orthodontic Extraction of Maxillary Premolars - A Randomized, Double-Blinded Study

BACKGROUND Local anaesthetics helps in preventing pain during surgical and dental procedures by blocking the peripheral nerves. The primary objective of this investigation was to compare and evaluate 4 % articaine hydrochloride (with 1 : 100000 adrenaline) and 2 % lignocaine hydrochloride (with 1 : 80000 adrenaline) in terms of pulpal anaesthesia, volume of anaesthetic solution administered, need of re-anaesthesia and difficulty of extraction during orthodontic extraction of maxillary first premolars. METHODS This prospective randomized, double-blinded study was conducted on 43 patients of less than 40 years of age requiring bilateral maxillary first premolar extractions for orthodontic purposes. Each patient was randomly assigned to receive either 2 % lignocaine hydrochloride or 4 % articaine hydrochloride for premolar extraction of one side and other solution was administered for premolar extraction of contralateral side spaced 1 to 3 weeks apart. In each patient, the difference in pulpal anaesthesia, volume of anaesthetic solution administered, need of re-anaesthesia, difficulty of extraction and duration of anaesthesia was assessed on administration of lignocaine hydrochloride and articaine hydrochloride. RESULTS Statistically significant difference in pulpal anaesthesia levels was found when the articaine and lignocaine groups (P > 0.05) were compared, with a higher mean pulpal anaesthesia among the articaine group. There was no difference in volume of anaesthetic solution administered on buccal and palatal side among the articaine and lignocaine groups. Only 2.3 % of patients in both the groups required re-anaesthesia on the buccal side. There was no significant difference in difficulty of extraction in both the groups. The articaine group had a longer mean duration of anaesthesia as compared to the lignocaine group which was highly significant. CONCLUSIONS Articaine may be used to replace lignocaine in orthodontic extraction of maxillary premolars with clinical advantages like higher pulpal anaesthesia and longer duration of anaesthesia. KEY WORDS Local Anaesthetic, Lignocaine Hydrochloride, Articaine Hydrochloride, Orthodontic Extraction, Prospective Study, Double-Blinded Study.

The effect of genetic polymorphisms on treatment duration following premolar extraction

To elucidate genetic factors affecting orthodontic treatment duration, we employed targeted next-generation sequencing on DNA from the saliva of 117 patients undergoing orthodontic treatment after premolar extraction. The clinical characteristics of patients are summarized, and the association of clinical variables with treatment duration was assessed. Patients whose treatment duration deviated from the average were classified into an extreme long group or an extreme short group. We identified nine single nucleotide polymorphisms (SNPs) of six genes that significantly differed in the two groups via targeted sequencing. The frequency of the CC genotypes of WNT3A, SPP1 (rs4754, rs9138), and TNFSF11, TT genotype of SPP1 (rs1126616), and GG genotype of SFRP2 was significantly higher in the extreme long group than in the short group. In the extreme short group, the TC genotype of SPP1, AA genotype of P2RX7, CT genotype of TNFSF11, and AG genotype of TNFRSF11A tended to exhibit higher frequency than in the long group. Taken together, we identified genetic polymorphisms related to treatment duration in Korean orthodontic patients undergoing premolar extraction. Our findings could lead to further studies predicting the prolongation of the orthodontic treatment duration, and will be of great aid to patients as well as orthodontists.

Key Factors Contributing to the Anchorage Loss of Maxillary First Molars: A Retrospective Study of 726 Extraction Cases

Background: Anchorage control is one of the key components in the treatment of extraction cases. However, why anchorage loss happens is still an unanswered question. The purpose of this study was to investigate the most important factors contributing to the anchorage loss of maxillary first molars in premolar extraction cases. Methods：The study enrolled 726 upper premolar extraction cases, including 214 male patients and 512 female patients, and the average age was 14 (range: 9-45 years old).Factors including physiological characteristics, treatment mechanics and cephalometric variables were collected and their influences on the angulation changes of maxillary first molars were analyzed. Results: The average angulation change of maxillary first molar after treatment was 2.81°, meaning the molar tipped forward during treatment by 2.81°. The change of UM/PP showed statistically significant difference in different sex ( male 3.84°±5.26 ° vs female 2.38°±5.10°), age (adult -0.05°±4.73 ° vs teenager 3.46°±5.07°), and molar relationship(Class II 3.28°±5.15°vs Class I 2.36°±5.19°). There are six variables accounted in the regression analysis (R=0.608, R²=37.0%). Among them, the pre-treatment molar tipping (Standardized Coefficients：-0.65) and the pre-treatment incisor/molar height ratio (Standardized Coefficients：-0.27)were the most important factors influencing anchorage loss during treatment.Conclusion: Compared with treatment-related factors, the patient’s physiological characteristics play a more important role in anchorage loss. The pre-treatment angulation of the maxillary first molar is the most contributing factor of the maxillary molar angulation changes, which are often predisposing anchorage loss.