Preface

This book is the outcome of the confluence of two initial projects: "Human Molars" led by Prof. BOURZGUI Farid and "Basics of Dental Morphology and Anatomy" by Prof. Zühre Akarslan. The experience of co-editing was very enriching for both editors and led to a final product that we hope will be very useful and valuable for our readers.

The book is divided into three sections:

**II**

**Chapter 9 147**

**Chapter 10 157**

Pathology and Clinical Considerations **163**

**Chapter 11 165**

**Chapter 12 193**

**Chapter 13 211**

**Chapter 14 237**

Pathology and Abnormality of the First Permanent Molar among Children

Orthodontic Management of Residual Spaces of Missing Molars: Decision

*by Hakima Aghoutan, Sanaa Alami, Amal El Aouame and Farid El Quars*

*by Sanaa Alami, Hakima Aghoutan, Meriem Bellamine and Farid El Quars*

Evolution of Dental Implant Shapes and Today's Custom Root Analogue

Impacted First and Second Permanent Molars: Overview

*by Mouna Hamza, Amal Chlyah, Bouchra Bousfiha, Bouchra Badre,* 

Root Canal Morphology and Anatomy

*by Jesús Alejandro Quiñones Pedraza*

*Maria Mtalsi, Hasna Saih and Samira El Arabi*

*by Esra Pamukcu Guven*

The C-Shaped Root Canal

**Section 3**

Factors

Implants

*by Ayse Sumeyye Akay*


As a final note, we would like to express our thanks to the authors of the different chapters and their respective teams, as well as all those who contributed to the final outcome of this book.

> **Farid Bourzgui** Professor and Head of Orthodontics Department, University Hassan II, Faculty of dentistry, Casablanca, Morocco

**Zühre Akarslan** Professor, Department of Oral and Maxillofacial Radiology, Gazi University Faculty of Dentistry, Ankara, Turkey

**1**

Section 1

Basic Principles -

Embryology and

Development

Section 1

Basic Principles - Embryology and Development

**3**

positioning.

bruxism, and may cause tooth wear.

**Chapter 1**

**Abstract**

(orofacial myology).

**1. Introduction**

Can Orofacial Structures Affect

*Amanda Valentim, Renata Furlan, Mariana Amaral* 

This chapter presents how orofacial muscles can affect teeth positioning, occlusion, and also the size/shape of teeth. Pressures exerted on teeth will be discussed in specific cases such as mouth breathing, chronic mastication disorders, oral habits, like thumb sucking or tongue thrust, and also when there is hyperfunction of masticatory muscles during sleep or wakefulness. In these situations, the imbalance of muscle forces brings undesirable consequences to the dentition. Each condition will be explained, showing which muscle is affected, how it changes, and what consequences to the teeth it brings. It is a chapter that shows how close the relationship is between dentistry and speech language pathology

**Keywords:** tooth, malocclusion, tongue, lip, cheek, bruxism, mastication

factors, it is often difficult to determine its specific cause [1].

Malocclusions are generally considered alterations in the normal field of craniofacial growth and morphology. Due to its different possibilities of etiological

There are four main structures that can cause malocclusions: the craniofacial skeleton, the teeth, the orofacial neuromuscular system, and other soft tissues. An example of how the musculature can generate malocclusion is the constantly open mandible in the mouth breathing leading to a constant anteriority of the tongue, which may force the incisors or prevent the eruption of the mandibular incisors [1]. Another example is that if a patient has a tongue with anterior posture during rest, the duration of this pressure, even if very light, may interfere with the eruption process or move the anterior teeth, resulting in an open bite [2]. There are also environmental influences, such as oral habits and balance between the orofacial musculature and the teeth, both at rest and during the functions [3]. Mouth breathing is one of these conditions. It causes muscle posture alteration that changes the balance in the oral cavity and modifies the forces exerted on teeth and bones, impacting facial growth and tooth

Other muscles that can influence tooth morphology are masseter and temporalis, which are jaw elevators. When they are active during rest or sleep, it is considered as

Tooth Morphology?

*and Fernanda Martins*

#### **Chapter 1**
