Morphological Features of the Crowns of Maxillary Second Primary Molar and First Permanent Molar: An Odontometric Study

Dental arch spatial changes after premature loss of first primary molars: a systematic review and meta-analysis of split-mouth studies

“…Reading of complete texts resulted in the inclusion of 11 studies, 9 longitudinal [ 9 , 15 , 30 – 36 ] and 2 cross-sectional [ 13 , 37 ]. Among them, there were five studies on Caucasians [ 13 , 30 , 33 , 34 , 37 ], five on Mongolians [ 9 , 15 , 31 , 32 , 35 ], and one on a Central European [ 36 ]. Five studies were excluded because they were non split-mouth (n = 5) or nonunilateral premature loss of a primary first molar (n = 1) [ 1 , 4 , 14 , 26 , 38 , 39 ] (Online Resource 1).…”

“…Quality assessment of the included studies is shown in Table 3 . Overall, nine studies were considered to be moderate risk of bias [ 9 , 15 , 30 – 33 , 35 – 37 ], and two were low risk of bias [ 13 , 34 ].…”

“…In general, the children included in these studies were expected to need the unilateral premature extraction of a primary first molar because of caries and/or failed pulp therapy, with an intact contralateral primary first molar available for use as the control. The research data were obtained in three ways: plaster cast [ 9 , 13 , 15 , 30 , 31 , 33 , 36 , 37 ], digital plaster cast [ 32 , 35 ], and direct intraoral measurement [ 34 ]. The initial study used plaster casts made from alginate impressions just before extraction of the primary first molar [ 30 , 32 ] or 2–14 days after extraction [ 9 , 15 , 31 , 36 ].…”

“…Five studies assessed dental arch changes [ 15 , 30 , 33 , 35 , 36 ]. However, no significant differences were found in arch width, arch length, or arch perimeter between the initial examination and the medium-term follow-up examination ( P > 0.05) (Fig.…”

“…Nine studies were considered to be moderate risk of bias [ 9 , 15 , 30 – 33 , 35 – 37 ], and two were low risk of bias [ 13 , 34 ]. In two articles [ 30 , 36 ], 27 individuals were excluded because of malocclusion, lack of second premolar buds on examination, the presence of mesiodens, additional tooth extractions, or no further follow up, which may not be serious sources of bias for the study outcomes.…”